,this file was produced from page images at the ,internet ,archive4 ,transcriber's ,note ,this book was transcribed from scans of the original found at the ,internet ,archive4 ,,arts ,,and ,,sciences ,no4 #i ,home-made ,toy ,motors ,a ,practical ,handbook ,giving ,detailed ,instructions for ,building ,simple but ,operative ,electric ,motors ,,by ,a4 ,p4 ,morgan ,,cole ,,morgan1 ,inc4 ,publishers of the ,arts and ,sciences ,series ,p4 ,o4 ,,box #dgc ,,city ,,hall ,,station ,,new ,,york1 ,n4 ,y4 ,,copyright #aiai ,,by ,,cole ,,morgan1 ,inc4 ,,chapter ,i4 ,,explaining ,,how ,,an ,,electric ,,motor ,,operates4 ,,some ,,principles ,,of ,,magnetism4 ,,the ,,difference ,,between ,a ,,shunt ,,and ,a ,,series ,,motor4 4444444444444444444444444444444444444444 44444444444444444444 ,,chapter ,,ii4 ,,the ,,construction ,,of ,,simple ,,toy ,,electric ,,motors4 4444444 ,,simplex ,,motor ,,with ,,three-,,pole ,,armature4 4444444444444444444444444 ,,how ,,to ,,make ,,the ,,simplex ,,overtype ,,motor4 4444444444444444444444444 ,,the ,,manchester ,,motor4 4444444444444444444444444444444444444444 444 ,,chapter ,,iii4 ,a ,magnetic ,attraction ,motor4 ,a ,motor ,having a ,laminated ,field and ,armature ,frame4 ,how to ,make an ,experimental ,induction ,motor4 ,how to ,make an ,electric ,engine4 4444444444444444444444444444 ,a ,,magnetic ,,attraction ,,motor4 444444444444444444444444444444444444 ,,how ,,to ,,construct ,a ,,motor ,,having ,a ,,laminated ,,armature ,,and ,,field ,,frame 4444444444444444444444444444444444444444 4444444444444444444 ,,how ,,to ,,make ,,an ,,experimental ,,induction ,,motor4 44444444444444444444 ,,how ,,to ,,build ,,an ,,electric ,,engine 444444444444444444444444444444444 ,,chapter ,,iv ,,small ,,power ,,motors 4444444444444444444444444444444444444 ,a ,,vertical ,,power ,,motor 4444444444444444444444444444444444444444 44 ,,connections ,,for ,,the ,,three ,,pole ,,armature 4444444444444444444444444 ,,connections ,,for ,,the ,,six-,,pole ,,armature 444444444444444444444444444 ,a ,,horizontal ,,power ,,motor4 444444444444444444444444444444444444444 ,,fig4 #a4--;,if a current of electricity is passed through a wire1 the wire will attract to itself iron filings4 4444444444444444444444444 ,,fig4 #b4--;,if a wire carrying a current of electricity is formed into a loop1 the space enclosed by the loop will become magnetic4 ,the arrows represent the paths of the lines of magnetic force4 44444444 ,,fig4 #c4--;,by forming the wire into several loops or a spiral so that the effect of the individual turns is concentrated in a small space1 an ,electromagnet is made4 444444444444444444444444444444444444444 ,,fig #d--,the strength of an electromagnet is proportional to the ampere turns4 ,the magnet illustrated above does not possess sufficient turns to be very strong4 4444444444444444444444444444444444444444 44 ,,fig4 #e4--;,an increase in the number of turns of wire has resulted in considerable increase in the magnetism and this magnet is able to lift a much greater weight than that shown in ,figure #d4 44444444444 ,,fig4 #f4--,the ,principle of the ,electric ,motor4 4444444444444444444444 ,,fig4 #g4--;,diagrams showing the difference between a ,shunt and a ,series ,motor4 4444444444444444444444444444444444444444 44444444444444444444 ,,fig4 #h4--;,details of the ,armature for the ,simplex ,two-pole ,motor4 444 ,,fig4 #i4--,showing the ,armature assembled on the shaft ready for winding4 4444444444444444444444444444444444444444 444444444444444444 ,,fig4 #aj4--;,a front view of the ,field ,frame4 4444444444444444444444444 ,,fig4 #aa4--,the completed ,field ,frame1 ready for winding4 444444444444 ,,fig4 #ab4--,the ,bearings4 4444444444444444444444444444444444444444 4444 ,,fig4 #ac4--,side view of the ,armature and ,commutator ,core assembled on the ,shaft before winding4 4444444444444444444444444444444444444444 4 ,,fig4 #ad4--,showing the ,motor assembled on the ,base so that all the parts may be lined up before winding4 44444444444444444444444444444 ,,fig4 #ae4--,the ,field ,frame with the ,winding in position4 444444444444 ,,fig4 #af4--,the ,armature ,winding before the ,commutator is completed4 4 ,,fig4 #ag4--,the completed ,armature showing how the ,commutator is constructed4 4444444444444444444444444444444444444444 44444444444444 ,,fig4 #ah4--;,details of the ,commutator4 4444444444444444444444444444444 ,,fig4 #ai4--,the completed ,motor4 4444444444444444444444444444444444444 ,,fig4 #bj4--;,details of the ,three-pole ,armature4 4444444444444444444444 ,,fig4 #ba4--,the ,three-pole ,armature assembled on the shaft4 4444444444 ,,fig4 #bb4--,showing the ,armature and ,shaft with the ,commutator ,core in position4 4444444444444444444444444444444444444444 44444444444444444 ,,fig4 #bc4--;,diagram showing how the coils are connected together so as to form a continuous winding4 4444444444444444444444444444444444444 ,,fig4 #bd4--,the completed ,three-pole ,motor4 44444444444444444444444444 ,,fig4 #be4--,the ,simplex ,overtype ,motor4 4444444444444444444444444444 ,,fig4 #bf4--;,details of the ,field ,frame for the ,overtype ,motor4 44444 ,,fig4 #bg4--,showing how the ,field is ,wound4 44444444444444444444444444 ,,fig4 #bh4--,the ,bearings4 4444444444444444444444444444444444444444 4444 ,,fig4 #bh4--,the ,manchester ,motor4 444444444444444444444444444444444444 ,,fig4 #cj4--;,details of the ,field ,frame4 444444444444444444444444444444 ,,fig4 #ca4--;,details of the ,field ,pedestal4 444444444444444444444444444 ,,fig4 #cb4--,showing how the ,field ,coils are ,wound4 4444444444444444444 ,,fig4 #cc4--;,details of the ,magnet ,bobbins4 444444444444444444444444444 ,,fig4 #cd4--,the completed ,electromagnets mounted on the ,yoke4 44444444 ,,fig4 #ce4--;,details of the ,armature ,shaft4 444444444444444444444444444 ,,fig4 #cf4--;,details of the ,standard which forms the upper bearings4 44 ,,fig4 #cg4--,the ,brass ,contact4 444444444444444444444444444444444444444 ,,fig4 #ch4--,the ,brush which bears against the ,contact4 444444444444444 ,,fig4 #ci4--,the completed ,magnetic ,attraction ,motor4 44444444444444444 ,,fig4 #dj4--,the completed ,electric ,motor4 4444444444444444444444444444 ,,fig4 #da4--;,details of the ,field ,frame4 444444444444444444444444444444 ,,fig4 #db4--,the ,assembled ,field ready for ,winding4 4444444444444444444 ,,fig4 #dc4--;,details of the ,armature ,laminations4 444444444444444444444 ,,fig4 #dd4--,the ,armature assembled on the ,shaft ready to ,wind4 4444444 ,,fig4 #de--,the ,commutator and ,method of connecting the ,armature ,coils4 ,,fig4 #df4--,the ,bearings4 4444444444444444444444444444444444444444 4444 ,,fig4 #dg4--;,brush and ,supporting ,block4 444444444444444444444444444444 ,,fig4 #dh4--;,a well known ,three-pole ,battery ,motor4 4444444444444444444 ,,fig4 #di4--,showing how a ,three-pole ,motor may be provided with ,starting ,coils and connected to form an ,experimental ,induction ,motor4 4444444444444444444444444444444444444444 44444444444444444444 ,,fig4 #ej4--,the completed ,engine4 444444444444444444444444444444444444 ,,fig4 #ea4--,the ,base4 4444444444444444444444444444444444444444 44444444 ,,fig4 #eb4--;,details showing the size of the ,magnet ,bobbin4 44444444444 ,,fig4 #ec4--,the ,frame which supports the ,electromagnets4 4444444444444 ,,fig4 #ed4--,the ,main ,bearings4 444444444444444444444444444444444444444 ,,fig4 #ee4--,the ,shaft4 4444444444444444444444444444444444444444 4444444 ,,fig4 #ef4--,showing the ,armature1 ,armature ,bearing and the ,connection ,rod4 4444444444444444444444444444444444444444 4444444444444444444444 ,,fig4 #eg4--;,details of the ,brushes and ,brush ,holder4 44444444444444444 ,,fig4 #eh4--,showing how a ,flywheel may be made out of sheet iron4 4444 ,,fig4 #ei4--;,a ,vertical ,battery ,power ,motor4 44444444444444444444444444 ,,fig4 #fj4--;,details of the ,field ,frame of the ,vertical ,motor4 44444444 ,,fig4 #fa4--,three-pole ,armature4 4444444444444444444444444444444444444 ,,fig4 #fb4--,six-pole ,armature4 444444444444444444444444444444444444444 ,,fig4 #fc4--,showing how the ,coils on a ,three-pole ,armature are connected to the ,commutator4 44444444444444444444444444444444444444 ,,fig4 #fd4--,showing how the ,coils on a ,six-pole ,armature are arranged and connected4 4444444444444444444444444444444444444444 444444444444 ,,fig4 #fe4--;,details of the ,commutator4 4444444444444444444444444444444 ,,fig4 #ff4--;,details of the ,bearings1 ,shaft1 and ,pulley4 44444444444444 ,,fig4 #fg4--,the ,brushes and ,brush ,holder4 4444444444444444444444444444 ,,fig4 #fh4--;,details of the ,field ,frame for the ,horizontal ,power ,motor4 ,,fig4 #fi4--;,front view of the ,field ,frame4 444444444444444444444444444 ,,fig4 #gj4--,the ,field ,magnet ,bobbin4 444444444444444444444444444444444 ,,fig4 #ga4--;,details of the ,shaft1 ,rocker ,arm1 ,bearing and ,pulley4 4444 ,,fig4 #gb4--,rear view of the completed ,horizontal ,motor4 4444444444444 ,,fig4 #gc4--,side view of the ,horizontal ,motor4 44444444444444444444444 ,,chapter ,i4 ,,explaining ,,how ,,an ,,electric ,,motor ,,operates4 ,,some ,,principles ,,of ,,magnetism4 ,,the ,,difference ,,between ,a ,,shunt ,,and ,a ,,series ,,motor4 99,an ,electric ,motor99 is a device for transforming electricity into mechanical power4 ,a generator1 or dynamo1 is constructed in almost the same identical manner as a motor but its purpose is just the opposite4 ,a dynamo transforms 99mechanical power into electricity994 ,a dynamo produces electric current1 but a motor 99consumes99 it4 ,some machines can be used either as a motor or dynamo--not all however4 ,of course most experimenters have in all probability seen many electric motors1 but it is more than likely that the exact operation is not thoroughly understood4 ,here is your chance to learn4 ,the little motors described in this book can each be made in two or three hours out of a few scraps of sheet iron1 magnet wire and screws4 ,the cost of the necessary materials is practically negligible4 ,one of the main advantages of these little motors is that they illustrate the actual principles that are used in the large motors1 such as are employed everywhere for practicable power purposes4 ,the iron parts may be made out of sheet iron or the ordinary so-called tin used in cocoa cans1 etc4 ,thin tin can be cut with an ordinary pair of shears4 ,sheet iron such as is used in making stovepipes1 etc41 is an excellent material to use in making these little motors4 ,sheet iron is usually heavier than tin and will have to be cut with a pair of snips4 ,greater skill will also then be required in bending the parts4 ,it is worth while noting however1 that the extra difficulty involved in using the heavier material is worth the trouble because it makes possible a more powerful and efficient motor4 ,the first and easiest type of motor to make is the ,simplex4 99,the ,principle on which an ,electric ,motor ,operates99 is really very simple4 ,if a current of electricity is passed through a copper wire1 the wire will attract to itself iron filings1 etc41 as long as the current continues to flow4 ,as soon as the current is shut off1 the filings drop away because the magnetism immediately disappears with the cessation of the current4 ,illustration3 ,,fig4 #a4--;,if a current of electricity is passed through a wire1 the wire will attract to itself iron filings4 ,if a wire1 carrying a current of electricity is formed into a loop1 the entire space enclosed by the loop will possess the properties of a magnet4 ,by forming the wire into several loops or a spiral the combined effect of all the individual turns is concentrated in a small space and a much more powerful field is produced4 ,if the coil is provided with an iron core1 the magnetism is much more concentrated and will exercise a very powerful attractive effect upon any neighboring masses of iron or steel4 ,such a coil is called an electromagnet4 ,illustration3 ,,fig4 #b4--;,if a wire carrying a current of electricity is formed into a loop1 the space enclosed by the loop will become magnetic4 ,the arrows represent the paths of the lines of magnetic force4 ,electromagnets play a very important part in the construction of electric motors4 ,the strength of an electro magnetic coil is proportional to its ampere turns4 ,the number of ampere turns in a coil is obtained by multiplying the number of amperes flowing through the coil by the number of turns of wire composing it4 ,illustration3 ,,fig4 #c4--;,by forming the wire into several loops or a spiral so that the effect of the individual turns is concentrated in a small space1 an ,electromagnet is made4 ,you can easily see the effect of turns of wire on an electromagnet by winding two or three turns of wire around a nail and connecting it to a battery4 ,these two or three turns will probably create enough magnetism to enable the nail to lift up one or two ordinary carpet tacks4 ,illustration3 ,,fig #d--,the strength of an electromagnet is proportional to the ampere turns4 ,the magnet illustrated above does not possess sufficient turns to be very strong4 ,then increase the number of turns to forty or fifty and note that the magnetism of the nail has increased greatly and that it now possesses power to pick up a larger number of tacks at a time4 ,from this one may be led to believe that the more turns of wire an electromagnet possesses1 the stronger it will be1 and while to a certain extent this is true1 it should be remembered that it is not simply 99turns99 that count but 99ampere turns99 and if the number of turns of wire is increased beyond a certain point the resistance of the coil to the electric current will become so great that the current in amperes flowing through the coil is greatly reduced and consequently also the magnetism is decreased4 ,illustration3 ,,fig4 #e4--;,an increase in the number of turns of wire has resulted in considerable increase in the magnetism and this magnet is able to lift a much greater weight than that shown in ,figure #d4 ,it will be found that the magnetism of an electromagnet is strongest at the ends4 ,these places are called the poles4 ,if you bring one pole of a small electromagnet1 formed by winding a nail with a few turns of wire1 near a compass needle1 you will find that it will attract one end of the compass needle and repel the other4 ,the end of the compass needle which points ,north is called a 99,north99 pole4 ,the ends of the electromagnet which attracts the ,north pole of the compass needle is a 99,south99 pole4 ,one of the most important laws of magnetism is that like poles repel each other and unlike poles attract each other4 ,a ,north and a ,south pole therefore tend to pull toward each other1 whereas two ,north poles or two ,south poles repel one another4 ,figure #f illustrates the principle of an electric motor4 ,it consists of a bar of iron marked ,a called the 99,armature99 and wound with a coil of wire called the armature winding4 ,the armature is the part of the motor which revolves4 ,illustration3 ,,fig4 #f4--,the ,principle of the ,electric ,motor4 ,each end of the armature winding is connected to one half of a brass ring called the commutator and marked ,c1 ,c1 in the illustration4 ,the two halves of the commutator are insulated from each other and are mounted on the armature shaft so that they revolve together with the armature4 ,the armature revolves between the ends of a horseshoe shaped piece of iron called the field4 ,the field is also wound with a coil of wire called the 99field winding99 or sometimes the field coil4 ,the armature and the field are both electromagnets4 ,two strips of copper1 ,b1 ,b1 bear against the commutator4 ,these are the 99brushes991 and their purpose is to lead the current to the armature coil4 ,one brush is connected to one end of the field coil4 ,the other end of the field coil and the other brush are connected to a source of electric current4 ,as soon as the current is turned on1 the armature and the field both become magnets4 ,the ,north pole of the field attracts the ,south pole of the armature and vice-versa4 ,the armature starts to move so that the poles will come opposite but as the commutator moves around and is turned over1 the current flows through the armature coil in the opposite direction4 ,this reverses the magnetism of the armature and that which was the ,south pole become the ,north pole and vice-versa4 ,illustration3 ,,fig4 #g4--;,diagrams showing the difference between a ,shunt and a ,series ,motor4 ,the armature poles will therefore have to move #ahj degrees in order that the ,south pole may come opposite the ,north pole of the field4 ,before it gets there1 however1 the commutator will have turned over again1 reversing the current in the armature and making it necessary to continue its journey again4 ,this process keeps up and so the armature revolves always trying to seek a new position which it is prevented from remaining at by the action of the commutator4 ,motors are said to be series or shunt wound depending on whether all the current flowing through the armature also passes through the field or whether it divides between the two as shown in ,figure #g4 ,,chapter ,,ii4 ,,the ,,construction ,,of ,,simple ,,toy ,,electric ,,motors4 ,the ,simplex ,motor is an interesting little toy which can be made in a couple of hours1 and when finished it will make an instructive model4 ,as a motor itself1 it is not very efficient1 for the amount of iron used in its construction is necessarily small4 ,the advantage of this particular type of motor and the method of making it is that it demonstrates the actual principle and the method of application that is used in larger machines4 ,illustration3 ,,fig4 #h4--;,details of the ,armature for the ,simplex ,two-pole ,motor4 ,the field of the motor is of the type known as the simplex while the armature is the ,siemen's ,h or two-pole type4 ,the field and the armature are cut from ordinary tin-plated iron1 such as is used in the manufacture of tin cans and cracker boxes4 ,the simplest method of securing good flat material is to get some old scrap from a plumbing shop4 ,an old cocoa tin or baking-powder can may1 however1 be cut up and flattened and will then serve the purpose almost as well4 ,illustration3 ,,fig4 #i4--,showing the ,armature assembled on the shaft ready for winding4 99,the ,armature99--,two strips of tin1 one-half of an inch by one and one-half inches1 are cut to form the armature4 ,they are slightly longer than will actually be necessary1 but are cut to length after the bending operations are finished4 ,mark a line carefully across the center of each strip4 ,then taking care to keep the shape symmetrical so that both pieces are exactly alike1 bend them into the shape shown in ,figure #h4 ,the small bend in the center is most easily made by bending the strip over a knitting-needle and then bending it back to the required extent4 ,illustration3 ,,fig4 #aj4--;,a front view of the ,field ,frame4 ,a piece of knitting-needle one and seven-eighths inches long is required for the shaft4 ,bind the two halves of the armature together in the position shown in ,figure #i4 ,bind them temporarily with a piece of iron wire and solder them together4 ,the wire should be removed after they are soldered4 ,illustration3 ,,fig4 #aa4--,the completed ,field ,frame1 ready for winding4 99,the ,field ,magnet99 is made by first cutting out a strip of tin five-eighths of an inch wide by five inches long and then bending it into the shape shown in ,figure #aa4 ,the easiest way of doing this with the most accuracy is to cut out a piece of wood as a form1 and then bend the tin over the form4 ,the dimensions shown in ,figure #aj should be used as a guide when making the form4 ,illustration3 ,,fig4 #ab4--,the ,bearings4 ,two small holes should be bored in the feet of the field magnet to receive ,no4 #h wood screws1 the purpose of which is to fasten the field to the base4 99,the ,bearings99 are shown in detail in ,figure #ab4 ,they are easily made by cutting from sheet tin4 ,care should be taken to make the bearings accurately so that the armature will be in the proper position when the motor is assembled4 ,two small washers1 serving as collars1 should be soldered to the shaft as shown in ,figure #ac4 99,the ,commutator ,core99 is formed by cutting a strip of paper three-eighths of an inch wide and about five inches long4 ,it should be given a coat of shellac on one side and allowed to dry until it gets sticky4 ,the strip is then wrapped around the shaft until its diameter is three-sixteenths of an inch4 ,the sticky shellac should be sufficient to hold the paper tightly in position when dry4 99,the ,base99 is cut from any ordinary piece of wood and is in the form of a block about two and one-half by one and seven-eighths by one-half inches thick4 ,illustration3 ,,fig4 #ac4--,side view of the ,armature and ,commutator ,core assembled on the ,shaft before winding4 99,assembling the ,motor99--,the parts must be carefully prepared for winding by covering with paper4 ,cut a strip of paper five-eighths of an inch wide and one and three-eighths inches long and give it a coat of shellac on one side4 ,as soon as it becomes sticky1 wrap it around one of the two upper vertical parts of the field magnet as indicated in ,figure #aa4 ,both sides of the field should be insulated with paper in this manner4 ,the armature is insulated in exactly the same way1 taking care that the paper covers the entire flat portion4 ,the field and armature are now ready for winding4 ,it is necessary to take proper precautions to prevent the first turn from slipping out of place4 ,the field should be wound first4 ,this is accomplished by looping a small piece of tape or cord over it at the point indicated by ,a in ,figure #ae4 ,the next two turns are then taken over the ends of the loop so as to embed them4 ,wind on three layers of wire on one side and then run the wire across to the other side and wind on three layers there4 ,the third layer of wire in the second coil should end at ,b4 ,it should be fastened into position by a loop of string so that it will not unwind4 ,illustration3 ,,fig4 #ad4--,showing the ,motor assembled on the ,base so that all the parts may be lined up before winding4 ,this method divides the field winding into two parts1 both of which are connected together4 ,the outside layer of the first coil is connected to the inside layer of the second coil4 ,the two coils really form one continuous winding divided into two parts4 ,after the winding is finished1 give it a coat of shellac4 ,the winding of the armature is somewhat more difficult4 ,the wire used for winding both the armature and the field should be ,no4 #be or ,no4 #bf ,b4 ,s4 ,gauge double cotton-covered4 ,illustration3 ,,fig4 #ae4--,the ,field ,frame with the ,winding in position4 ,in order to wind the armature1 cut off about seven feet of wire and double it back to find the center4 ,then place the wire diagonally across the center of the armature so that there is an equal length on both sides4 ,place a piece of paper under the wire at the crossing point to insulate it4 ,then1 using one end of the wire1 wind four layers on half of the armature4 ,tie the end down with a piece of thread and wind on the other half4 ,the ends of the wire are cut and scraped to form the commutator segments4 ,figure #ag shows how this is done4 ,illustration3 ,,fig4 #af4--,the ,armature ,winding before the ,commutator is completed4 ,bend the wires as shown so that they will fit closely to the paper core4 ,bind them tightly into position with some silk thread4 ,use care so that the two wires do not touch each other4 ,cut the free ends of the wire off close to the core4 ,when finished1 the relative positions of the armature and the commutator should be as shown in ,figure #ag4 ,figure #ad shows how the motor is assembled4 ,the windings are not shown for the sake of clearness4 ,the armature should be exactly in the center of the field4 ,the bearing holes should be in the correct position and should permit the armature to revolve freely4 ,illustration3 ,,fig4 #ag4--,the completed ,armature showing how the ,commutator is constructed4 ,the armature should not scrape against the field at any point1 but should clear it by about one-sixteenth of an inch4 ,the brushes are made by flattening a piece of wire by a few light hammer blows4 ,the brushes are fastened under a small clamp formed by a strip of tin held down at each end with a wood screw4 ,they can be adjusted to the best advantage only under actual working conditions when the current is passing through the motor4 ,one or two dry cells should be sufficient to operate the motor4 ,the completed motor is shown in ,figure #ai4 ,one end of the winding is connected to one of the brushes4 ,the other brush and the other end of the field form the terminals to which the battery is connected4 ,the motor1 being of the two-pole armature type1 must be started when the current is turned on1 by giving it a twist with the fingers4 ,illustration3 ,,fig4 #ah4--;,details of the ,commutator4 ,put a drop of oil on the bearings1 make sure that the brushes bear firmly but not tightly against the commutator1 connect the battery and your motor is ready to run4 ,it will spin at a high rate of speed4 ,illustration3 ,,fig4 #ai4--,the completed ,motor4 ,,simplex ,,motor ,,with ,,three-,,pole ,,armature4 ,the form of ,simplex motor which has just been described has only one drawback which prevents it from being a first class motor in every respect1 namely1 the armature has only two poles and the motor is therefore not self-starting1 but must be given a twist with the fingers in order to start it rotating4 ,a ,two-pole armature is the easiest for the young experimenter to make and that is the reason that it has been described first4 ,all large power motors are provided with armatures having a large number of poles so as to be self-starting and to give as steady a pull as possible4 99,the ,armature99--,the method of making a three-pole armature is practically the same as that of making one having only two poles4 ,three strips of tin1 one-half an inch by one and one-half inches are necessary4 ,they are purposely made a little longer than is actually required in order to form the armature and are cut to length after the finish of the bending operations4 ,illustration3 ,,fig4 #bj4--;,details of the ,three-pole ,armature4 ,mark a line carefully across the center of each strip4 ,then bend them into the shape shown in ,figure #bj1 taking care to keep the shape symmetrical so that all three pieces are exactly alike4 ,the bend in the center which must fit over the shaft is most easily made by bending the strips over a knitting-needle and then bending them back the required amount4 99,the ,shaft99 is formed by a piece of knitting-needle1 one and seven-eighths of an inch long4 ,assemble the three pieces1 forming the armature1 on the shaft as shown in ,figure #ba4 ,bind them temporarily together with a piece of iron wire and then solder them along the edges4 ,the iron wire should be removed after they are soldered4 99,the ,commutator ,core99 is formed by cutting a strip of paper1 three-eighths of an inch wide and about five inches long4 ,it should be given a coat of shellac on one side and allowed to dry until it becomes sticky4 ,illustration3 ,,fig4 #ba4--,the ,three-pole ,armature assembled on the shaft4 ,the strip is then wrapped around the shaft until its diameter is three-sixteenths of an inch4 ,the sticky shellac should be sufficient to hold the paper tightly in position when dry and to form a hard1 firm core4 ,the illustration in ,figure #bb shows the position of the core on the shaft in relation to the rest of the armature4 99,the ,winding of the ,armature99 may seem somewhat more difficult at first than was the case with the two-pole armature1 but it is really very easy4 ,the wire used for this purpose should be ,no4 #be or ,no4 #bf ,b4 ,s4 ,gauge1 double cotton-covered4 ,single cotton-covered wire for this purpose is liable to give trouble on account of short circuits4 ,in order to wind the armature1 cut three pieces of wire about three and one-half feet long4 ,wrap a strip of paper around each section of the armature so that the sharp edges of the tin will not cut through the insulation on the wire and then wind four layers of wire on each section of the armature4 ,illustration3 ,,fig4 #bb4--,showing the ,armature and ,shaft with the ,commutator ,core in position4 ,each section should be wound in the same direction as the others4 ,the ends of the wires should be scraped free from insulation and connected together as follows3 ,connect the outside end of one section to the inside end of the next section4 ,we will presume that the three sections of the armature are lettered ,a1 ,b1 and ,c4 ,connect the outside end of ,a to the inside of ,b2 the outside of ,b to the inside end of ,c and the outside of ,c to the inside of ,a4 ,those portions of the wire forming the connections between the three sections1 are used to form the commutator segments1 in the same manner as the ends of the wires in the case of the two-pole armature1 only in this instance there are three sections to the armature4 ,illustration3 ,,fig4 #bc4--;,diagram showing how the coils are connected together so as to form a continuous winding4 ,bend the wires so that they will fit closely to the paper core and bind them tightly into position with some silk thread4 ,a section of the commutator should come opposite the space between each section of the armature4 99,the ,field ,magnet99 is exactly like that used in making the ,simplex motor with the two-pole armature4 ,it is made by first cutting out a strip of tin five-eighths of an inch wide by five inches long and then bending it into the shape shown in ,figures #aj and #aa4 ,the easiest way of doing this with reasonable accuracy is to cut out a piece of wood for a form and then bend the tin over the form4 ,two small holes should be bored in the feet of the field magnet so as to enable the field to be fastened to the base4 ,the field is wound with the same size of wire used on the armature4 ,the winding is started by looping a small piece of tape or cord over the frame at the point indicated by ,a in ,figure #ae4 ,the next two turns are then wound over the ends of the loop so as to hold them down4 ,wind on three layers of wire on one side and then run the wire across to the other side and wind on three layers there4 ,the third layer of wire in the second coil should end at ,b4 ,it should be fastened in position by a loop of string so that it will not unwind4 ,this method divides the field winding into two parts1 both of which are connected together4 ,the outside layer of the first coil is connected to the inside layer of the second coil4 ,the two coils really form one continuous winding divided into two parts4 ,the illustration in ,figure #bc should make this clear4 ,after the winding is finished1 give it a coat of shellac4 99,the ,bearings99 are shown in detail in ,figure #ab4 ,they are easily made4 ,care should be taken to make the bearings very accurate so that the armature will be in the proper position when the motor is assembled4 ,two small washers1 serving as collars to bear against the inside of the bearings and keep the armature in the field should be soldered to the shaft as shown in ,figure #ac4 99,the ,base99 is cut from any ordinary piece of wood and should be in the form of a rectangular block about two and one-half inches by one and seven-eighths inches wide1 and one-half inch thick4 ,the completed motor is shown in ,figure #bd4 ,be sure that the armature does not scrape against the field at any point but clears it by about one-sixteenth of an inch all around4 ,the brushes are fastened under a small clamp made from a strip of tin held down at each end by a small wood screw4 ,the brushes are made by flattening the end of a piece of copper wire with a few light hammer blows4 ,the brushes can be best adjusted under actual working conditions when the current is passing through the motor4 ,one end of the field winding is connected to the brush marked ,c1 in ,figure #bd4 ,the other brush1 ,a and the other end of the field winding1 ,b1 form the terminals to which the battery is connected4 ,this forms what is known as a series connected motor1 because the armature and the field are in series and the current must pass from one to the other4 ,illustration3 ,,fig4 #bd4--,the completed ,three-pole ,motor4 ,after you have finished assembling the motor1 put a drop of oil on the bearings1 make certain that the brushes are properly adjusted1 connect the battery1 and your motor is ready to run4 ,one or two dry cells should furnish sufficient current to run the motor at high speed4 ,,how ,,to ,,make ,,the ,,simplex ,,overtype ,,motor4 ,the method of construction which has been outlined in making the two ,simplex motors1 just described1 also lends itself to the construction of many other simple and interesting forms of motors4 ,figure #be shows a form of motor which is essentially the same as that shown in ,figure #bd except that the field has been turned upside down and the armature is at the top of the motor instead of the bottom4 ,illustration3 ,,fig4 #be4--,the ,simplex ,overtype ,motor4 ,the detailed dimensions of the field are shown in ,figure #bf4 ,it is made by cutting out a4 strip of tin five-eighths of an inch wide and five inches long4 ,this strip is then bent into the shape shown in ,figures #bf and #bg4 ,this form of field is really very similar to that shown in ,figure #ae except that the two feet are omitted and it has been turned upside down4 ,the method of making ft is the same4 ,illustration3 ,,fig4 #bf4--;,details of the ,field ,frame for the ,overtype ,motor4 ,the field should be wound with either ,no4 #be or ,no4 #bf ,b4 ,s4 ,gauge double cotton-covered wire4 ,it should be carefully prepared for winding by a strip of shellaced paper around each of the two straight parts of the field magnet where the winding is to be placed4 ,then proceed with the winding in exactly the same manner as in the case of the field shown in ,figure #ae4 ,the armature used is of the the three-pole type and is exactly the same as that shown in ,figures #bj1 #ba and #bb4 ,illustration3 ,,fig4 #bg4--,showing how the ,field is ,wound4 ,the bearings will have to be made much higher on account of the armature being higher than the base4 ,the details of the bearings are shown in ,figure #bh4 ,they are cut out of sheet tin4 ,care should be taken to make them accurately so that the armature will be in the proper position when the motor is assembled4 ,the base is a block of wood two and one-half inches long1 one and seven-eighths of an inch wide and one-half inch thick4 ,the field is fastened to the base by four small wood screws4 ,the exact method of assembling the motor is probably best understood by studying the illustration in ,figure #be4 ,illustration3 ,,fig4 #bh4--,the ,bearings4 ,,the ,,manchester ,,motor4 ,those readers who have made the motors already described1 are no doubt anxious to proceed with the construction of some models which bear a greater resemblance to the large motors commonly employed to furnish power4 ,figure #bi shows a motor of the ,manchester type4 99,the ,field99 of this machine is made from a strip of heavy sheet tin1 one-half inch wide and about six inches long1 bent to shape and joined in the center of the bottom pole piece1 just above the pedestal4 ,it is best to cut the strip a little long and then reduce it to the exact length required after the bending operations have been finished4 ,the illustration in ,figure #cj shows the details and dimensions of the field4 ,the field should be bent into shape with the aid of a pair of pliers and a wooden form1 in the same manner employed in making the motors already described4 ,illustration3 ,,fig4 #bh4--,the ,manchester ,motor4 ,the field frame is supported by a pedestal4 ,the pedestal is formed by another strip1 one-half inch wide1 soldered to the field at right angles1 underneath the joint in the lower pole piece4 ,the pedestal should be firmly soldered to the field1 care being taken to see that the solder runs well into the joints4 ,then bend the ends of the pedestal down to form two feet as shown in the illustration4 ,the feet should be bent so as to bring the center of the armature tunnel five-eighths of an inch above the base4 ,two small holes should be bored in the pedestal1 at each side1 so that the motor can be screwed fast to a wooden base4 ,illustration3 ,,fig4 #cj4--;,details of the ,field ,frame4 99,winding the ,field99--,it will be necessary to proceed with the winding of this motor in a slightly different manner from that followed in making the other motors4 ,the wire cannot be wound on as easily as before and it will be necessary to wind the required length of wire onto a small spool or bobbin1 which can be passed through the field4 ,double cotton-covered wire is the best for the purpose4 ,either ,no4 #be or ,no4 #bf ,b4 ,s4 ,gauge may be used4 ,a strip of paper should be wrapped around the field frame at all points where the wire is liable to touch1 so as to guard the insulation against possible abrasion4 ,figure #cb shows the method which should be followed in winding the coils4 ,both parts of the winding should be started at the bottom of the field and wound in the direction indicated4 ,b and ,d are the starting ends ,wind on three layers of wire in each coil4 ,the terminals1 ,b and ,c1 should be connected together after the winding is finished4 99,the ,armature99--,the method of making the armature is exactly the same as that which has already been described4 ,three strips of tin1 one-half inch wide and one and one-half inches long are required4 ,they are purposely made slightly longer than is actually necessary and are cut to length after the finish of the bending operations4 ,illustration3 ,,fig4 #ca4--;,details of the ,field ,pedestal4 ,mark a line carefully across the center of each of the three strips and then bend them into the shape shown in ,figure #bj1 making certain to keep the shape symmetrical so that all three1 pieces are exactly alike4 ,the bend in the center of each strip should fit nicely over the shaft4 ,this result is most easily reached by bending the strips over a knitting-needle and then bending them back the required amount4 ,illustration3 ,,fig4 #cb4--,showing how the ,field ,coils are ,wound4 99,the ,shaft99 is a piece of knitting-needle one and seven-eighths of an inch long4 ,assemble the three strips on the shaft as shown in ,figure #ba and bind them temporarily together with a piece of iron wire4 ,then solder the edges together and remove the wire4 99,the ,commutator ,core99 is formed of a strip of paper1 three-eighths of an inch wide and about five inches long1 wrapped around the shaft until the diameter of the small cylinder thus formed is three-sixteenths of an inch4 ,the paper strip should be given a coat of shellac on one side and allowed to dry until it becomes sticky before it is wrapped around the shaft4 ,the sticky shellac should be sufficient to hold the paper tightly in position when dry and to form a hard1 firm core when dry4 99,the ,winding of the ,armature99 is not difficult4 ,the size of the wire used should be ,no4 #be or ,no4 #bf ,b4 ,s4 ,gauge1 double cotton-covered4 ,wrap a strip of paper around each section of the armature so that the wire will be protected from any sharp edges on the tin which might cut through the insulation4 ,wind four layers of wire on each section of the armature4 ,each section should be wound in the same direction as the others4 ,the terminals of the wires should be scraped clean and connected together in the following manner3 ,connect the outside end of one section to the inside end of the next section4 ,we will presume that the three sections of the armature are lettered ,a1 ,b and ,c4 ,connect the outside end of ,a to the inside of ,b2 the outside of ,b to the inside end of ,c and the outside end of ,g to the inside of ,a4 ,the portion of the wires forming the connections between the three armature coils are used to form the three sections of the commutator4 ,bend the wires so that they will fit closely to the paper core and bind them tightly into position with silk thread4 99,two ,bearings99 are required to support the armature4 ,they are cut out of sheet iron or brass and are shown in detail in ,figure #ab4 ,extra care should be exercised in making the bearings to insure their accuracy so that the armature will be in the proper position when the motor is assembled and run freely4 ,two small washers or wire rings1 to serve as collars and keep the armature in the center of the field1 should be soldered to the shaft as shown in ,figure #bb4 99,the ,base99 is a square block of wood1 two and one-half inches wide1 two and one-half inches long and three-eighths of an inch thick4 ,the completed ,manchester motor is shown in ,figure #bi4 ,the brushes are made by flattening the ends of two pieces of copper wire4 ,each brush is fastened under a small clamp made from a strip of tin held down at each end by a small round-headed wood screw4 ,be sure that the armature is exactly in the center of the field1 does not scrape at any point and turns perfectly freely4 ,the armature and the field windings should be connected in series4 ,the terminals of the field marked ,b in ,figure #cb should be connected to the brush clamp marked ,c in ,figure #bi4 ,the terminal of the field marked ,c in ,figure #cb forms one terminal of the motor4 ,the other is the brush clamp ,a4 ,oil the bearings of the motor1 adjust the brushes and it will be ready to run4 ,,chapter ,,iii4 ,a ,magnetic ,attraction ,motor4 ,a ,motor ,having a ,laminated ,field and ,armature ,frame4 ,how to ,make an ,experimental ,induction ,motor4 ,how to ,make an ,electric ,engine4 ,a ,,magnetic ,,attraction ,,motor4 ,this motor differs from those which have already been described1 in that no wire is wound on the armature4 99,the ,field ,coils99 consist of two electro-magnets wound upon iron cores one and one-eighth inches long and five-sixteenths inches in diameter4 ,each core is fitted with two fibre heads1 one-sixteenth of an inch thick and seven-eighths of an inch in diameter so as to form a bobbin as shown in ,figure #cc4 ,the bobbins are wound with ,no4 #bb ,b4 ,s4 ,gauge single cotton-covered magnet wire4 ,the magnets are connected in series so that the current flows through them in opposite directions4 ,illustration3 ,,fig4 #cc4--;,details of the ,magnet ,bobbins4 99,the ,armature99 is a strip of soft iron one and three-quarters inches long1 three-eighths of an inch wide and three thirty-seconds thick4 ,a one-eighth inch hole bored through the center of the armature and the latter forced upon a shaft one and seven-eighths inches long4 ,the lower end of the shaft is pointed and rests in a small hole in the magnet yoke1 half way between the two coils4 ,the magnet-yoke is a strip of soft ,iron or steel two and one-half inches long1 seven-eighths inches wide and one-eighth of an inch thick4 ,illustration3 ,,fig4 #cd4--,the completed ,electromagnets mounted on the ,yoke4 ,the magnets are mounted on a wooden base1 five inches long1 three inches wide and three-eighths of an inch thick1 by means of two #h-cb machine screws which pass upward from the bottom of the base into the bottom of the magnets4 ,the yoke is placed under the' magnets1 between them and the base4 ,the screws pass through two holes1 one and one-eighth inches apart4 ,the armature is supported in position over the electromagnets by means of a standard bent out of a strip of sheet brass4 ,the details of the standard are shown in ,figure #cf4 ,the standard is fastened to the base by means of two small wood screws4 ,illustration3 ,,fig4 #ce4--;,details of the ,armature ,shaft4 ,the armature should just clear the top of the electromagnets when the lower end of the shaft is resting in the socket in the yoke4 ,the shaft should be perfectly vertical and revolve freely without friction4 ,the lower end of the shaft carries a small brass contact which is forced into position4 ,the exact shape and dimensions of this contact are shown in ,figure #cg4 ,the holes through the center should be slightly smaller than the diameter of the shaft1 so that when the contact is forced into position it will remain secure and not move4 99,the ,brush99 which bears against the contact is illustrated in ,figure #ch4 ,this is cut out of spring copper or brass and made according to the shape and dimensions shown in the illustration4 ,the brush is fastened to the base by means of a round-headed brass wood screw4 ,the proper method of assembling the motor and its appearance when finished are best understood from the illustration in ,figure #ci4 ,illustration3 ,,fig4 #cf4--;,details of the ,standard which forms the upper bearings4 99,the ,binding ,posts99 consist of machine screws provided with hexagonal nuts and thumb screws1 such as that supplied on dry batteries4 ,one binding post passes through the end of the brush and connects with it4 ,the other binding post is mounted at the left hand forward corner of the base4 ,one terminal of the electromagnets leads to this binding post4 ,the other terminal is placed under the head of one of the screws which hold the standard to the base4 ,illustration3 ,,fig4 #cg4--,the ,brass ,contact4 ,the contact and the brush will have to be most carefully adjusted before the motor will run4 ,the tip of the contact should make contact with the brush just before the armature starts to swing over the electromagnets and break the circuit just as the armature is actually over4 ,the exact position will have to be found by a little experimenting4 ,it is very necessary that the brush should be so adjusted that it only touches the ends of the contact as it swings around4 ,illustration3 ,,fig4 #ch4--,the ,brush which bears against the ,contact4 ,illustration3 ,,fig4 #ci4--,the completed ,magnetic ,attraction ,motor4 ,the operation of the motor is very simple4 ,when a battery is connected to the binding posts the circuit is not complete so that the coils are magnetized and can attract the armature until the contact touches the brush4 ,when the contact and the brush touch1 however1 the circuit is completed and the armature will be drawn toward the electromagnets4 ,as soon as it reaches a position over the ends of the cores1 the circuit should be broken so that the momentum will carry the armature past and around into such position that the opposite end of the contact touches the brush and the operation is repeated4 ,a magnetic attraction motor of this type will usually have to be started by giving the shaft a twist with the fingers4 ,,how ,,to ,,construct ,a ,,motor ,,having ,a ,,laminated ,,armature ,,and ,,field ,,frame ,it is an easy matter to make a strong electric motor suitable to operate on batteries by the exercise of a little careful workmanship4 ,illustration3 ,,fig4 #dj4--,the completed ,electric ,motor4 ,the field frame and armature of the motor shown in ,figure #dj are laminated1 that is1 built up of separate sheets of iron4 ,they may be made out of sheet tin or ordinary stove pipe iron4 ,the cheapest and simplest method of securing good flat material is to get some old scrap from a tinner's or plumbing shop4 99,the ,details of the ,field99 are shown in ,figure #da4 ,the exact shape and dimensions can be understood by reference to the illustration4 ,lay out one lamination very carefully as a pattern4 ,cut it out and smooth up the edges1 making certain that it is perfectly true to size and shape4 ,then use it as a template to lay out the other laminations by placing it on the metal and scribing a line around the edges with a sharp pointed needle4 ,enough laminations should be cut out to make a pile five-eighths of an inch high when tightly pressed together4 ,illustration3 ,,fig4 #da4--;,details of the ,field ,frame4 99,the ,armature99 is made in exactly the same manner as the field frame1 that is1 by cutting out a pattern according to the shape and dimensions shown in ,figure #dc and using it as a template to lay out the other laminations4 ,enough should be cut to make a pile five-eighths of an inch high when tightly squeezed together4 ,the armature is one and three-sixteenths inches in diameter4 ,the hole in the field frame which accommodates the armature is one inch and one-quarter in diameter so that there is a space in between for the armature to revolve in4 ,the hole through the center for the shaft should be of such diameter that the laminations will force very tightly on a shaft one-eighth of an inch in diameter4 ,the laminations should be very carefully flattened and then forced over the steel shaft which is two and one-eighth inches long4 ,clean up all the rough edges with a file and smooth the outside so that it will revolve properly in the field without scraping4 ,figure #dd illustrates the armature assembled on the shaft and ready to be wound4 99,the ,armature ,windings99 consist of four layers of ,no4 #bb ,b4 ,s4 ,gauge double cotton covered magnet wire wound around each leg4 ,the iron should be very carefully insulated with shellaced paper before the wire is put in position so that there will not be any danger of short circuit due to the sharp edges of the metal cutting through the insulation4 ,each leg should contain the same number of turns of wire and all should be wound in the same direction4 ,illustration3 ,,fig4 #db4--,the ,assembled ,field ready for ,winding4 99,the ,commutator99 is illustrated in ,figure #de4 ,it consists of a piece of brass tubing seven-sixteenths of an inch long1 five-sixteenths inside and three-eighths of an inch outside4 ,it should be forced onto a piece of fibre five-sixteenths of an inch in diameter and seven-sixteenths of an inch long4 ,split the tube1 into three equal parts by dividing it longitudinally with a hacksaw4 ,make a fibre ring which will force onto the tube very tightly when it is in position on the fibre core and so hold the three commutator sections firmly in position4 ,the sections should be arranged so that there is a small space between each two and they are perfectly insulated from each other4 ,the fibre core should have a one-eighth inch hole through the center so that it may be forced tightly onto the shaft and up against the armature after the windings are in position4 ,the commutator should be in such a position that the split between each two sections comes directly opposite the centre of each winding4 ,suppose that the windings are lettered ,a1 ,b1 and ,c1 the commutator section between ,a and ,b is numbered #a1 that between ,a and ,c is ,no4 #b1 and the one between ,c and ,b is ,no4 #c4 ,then the inside terminal of ,b is connected to the outside terminal of ,a and soldered to the end of commutator section ,no4 #a close to the winding4 ,the inside end of ,b is connected to the outside terminal of ,c and to commutator section ,no4 #b4 ,the inside end of winding ,c is connected to the outside of ,b and to commutator section ,no4 #c4 ,the connection of the armature windings to the commutator are represented by the diagram in ,figure #de4 ,illustration3 ,,fig4 #dc4--;,details of the ,armature ,laminations4 99,the ,field ,winding99 consists of five layers of ,no4 #ah ,b4 ,s4 double cotton covered wire4 ,a much neater job may be made of this part of the work if two fibre heads are cut to slip over the field and support the ends of the winding as shown in the illustration in ,figure #dj4 ,illustration3 ,,fig4 #dd4--,the ,armature assembled on the ,shaft ready to ,wind4 99,the ,bearings99 are illustrated in ,figure #df4 ,they are made out of three-eighths inch brass strip one-sixteenth of an inch thick by bending and drilling as shown in the illustration4 ,the location of the holes is best understood from the drawing4 ,the larger bearing is assembled on the field at the side towards the commutator4 ,assembling the motor is a comparatively easy matter if it is done properly and carefully4 ,the bearings are mounted on the field frame by screws passing through the holes ,b and ,b into a nut on the outside of the bearing at the opposite side of the field4 ,the armature should revolve freely without binding and without any danger of scraping against the field4 ,slip some small fibre washers over the ends of the shaft between the armature and the bearings so as to take up all end play4 99,the ,brushes99 are made of spring copper according to the shape and dimensions shown in ,figure #dg4 ,they can be cut out with a pair of snips4 ,each brush is mounted on a small fibre block supported on the large motor bearing4 ,the holes marked ,a and ,c in the illustration should be threaded with a #d-cf tap4 ,the hole ,b should be made one-eighth of an inch in diameter and drilled all the way through the block4 ,the holes1 ,a and ,c are used to fasten the blocks to the bearing4 ,the brushes are fastened to the blocks by means of a #f-cb screw with a nut on the lower end4 99,the ,base99 is a rectangular block1 three inches wide1 three and one-half inches long and three-eighths of an inch thick4 ,the motor is fastened to the base by four small right angled brackets bent out of strip brass and secured to the field frame by two machine screws passing through the holes1 ,h and ,h1 into a nut at the opposite end4 ,illustration3 ,,fig4 #de--,the ,commutator and ,method of connecting the ,armature ,coils4 ,one terminal of the field winding is connected to a binding post mounted on the base4 ,the other terminal of the field is connected to the right hand brush4 ,the end of the wire should be placed under the head of the screw which holds the brush to the fibre block4 ,the brush should be on the under side of the block so that it bears against the under side of the commutator4 ,illustration3 ,,fig4 #df4--,the ,bearings4 ,the left hand brush bears against the upper side of the commutator and is connected to a second binding post on the base of the motor4 ,this makes it a series motor1 that is1 the armature and the field are connected in series4 ,illustration3 ,,fig4 #dg4--;,brush and ,supporting ,block4 ,the motor is now ready to run4 ,put a drop of oil on each bearing and make certain that the curved portion of the brushes bear firmly against the centre of the commutator on opposite sides4 ,the armature having three poles1 should start without assistance and run at high speed as soon as the current-is applied4 ,two cells of dry or other battery should be sufficient4 ,the motor may be fitted with a small pulley so that its power may be utilized for driving small models4 ,,how ,,to ,,make ,,an ,,experimental ,,induction ,,motor4 ,a motor having a three-pole armature will run on alternating current as well as on direct current and can be operated on the #aaj volt ,a4 ,c4 current in series with a suitable resistance4 ,the average experimenter is probably aware of this but did you know that it can also be operated on alternating current as an 99induction motor99 and that it will then run 99without brushes99 and without current being led into the armature8 ,in order to make an induction motor out of an ordinary three-pole battery motor such as that shown in ,figure #dh it is merely necessary to remove the brushes and bind a piece of bare copper wire around the commutator so that it short circuits the segments4 ,the alternating current should be led into the field coil4 ,a step down transformer will prove very useful for producing a low voltage alternating current which may be connected directly to the field coil4 ,if a transformer is not available1 the #aaj v4 alternating current can be used1 provided that a proper resistance such as a lamp bank1 be placed in series with the motor4 ,if the current is turned on and the armature is then speeded up by giving it a couple of sharp twists1 or winding a string around the shaft and then pulling it as one would spin a top1 the motor will continue to revolve at a good rate of speed4 ,illustration3 ,,fig4 #dh4--;,a well known ,three-pole ,battery ,motor4 ,it may prove easier to start the motor if the armature is speeded up before the current is turned on4 ,as soon as a good speed is reached1 turn on the current and the armature should continue to run4 ,commercial induction motors are self starting1 and are provided with a hollow armature1 which contains a centrifugal governor4 ,when the motor is at rest or starting1 four brushes press against the commutator and divide the armature coils into four groups4 ,after the motor has attained the proper speed the governor is thrown out by centrifugal force and pushes the brushes away from the commutator4 ,at the same time a metal ring is pressed against the interior of the commutator1 short circuiting all the sections and making each coil a complete circuit of itself4 ,it would be very difficult to provide a small three-pole toy motor with such a governor and short-circuiting device in order to make it self-starting4 ,it is however possible to accomplish this in another way1 by a very simple device4 ,this consists in providing the armature with another set of coils for use in starting only4 ,the brushes are allowed to remain on the motor but are only used for starting4 ,the leads of the armature winding are removed from the commutator and are all connected together4 ,then two or three layers of wire are wound over the coils to form new coils which are similar to the old ones but smaller4 ,illustration3 ,,fig4 #di4--,showing how a ,three-pole ,motor may be provided with ,starting ,coils and connected to form an ,experimental ,induction ,motor4 ,these new coils are connected to the commutator in the same way as the old ones were before being removed1 just as if the motor was to be used in the ordinary manner4 ,a two-point switch will be necessary in order to complete the arrangements4 ,the connections should be made as in ,figure #di4 ,the switch should be thrown to the right1 on contact ,a1 for starting so that the current flows through the field and through the extra coils on the armature in the ordinary way4 ,as soon as the motor has reached its speed1 throw the switch to the left so that the current flows through the field only and the motor will continue to run by induction4 ,,how ,,to ,,build ,,an ,,electric ,,engine ,an electric engine is really a form of electric motor but differs from the most common form of the latter in that the armature1 instead of revolving1 oscillates back and forth1 like the piston of a steam or gasoline engine4 ,electric engines are not as efficient as electric motors from the standpoint of the amount of power delivered in proportion to the current used1 but they make very interesting models and the young experimenter will derive fully as much pleasure in constructing one as from the construction of an electric motor4 ,illustration3 ,,fig4 #ej4--,the completed ,engine4 ,various forms of electric engines were made before the first practical electric motor was invented4 ,they amounted to little more than curiosities however1 and could only be used where the expense of electric current was not to be regarded4 ,the engine illustrated in ,figure #ej is of the double action type4 ,it is provided with two electromagnets arranged so that one pulls the armature forward and the other pulls it back4 ,the motion of the armature is transmitted to the shaft by means of a connecting rod and crank4 ,it is very simple to build and the design is such that it will operate equally well whether it is made large or small4 ,if you do not happen to have all the necessary materials to build an engine according to the dimensions shown in the drawings1 you can make it just one-half that size1 and it will work equally well although it will1 of course1 not give as much power4 ,illustration3 ,,fig4 #ea4--,the ,base4 ,the complete engine is shown in ,figure #ej4 ,all the various parts have been marked so that you can easily identify them in the other drawings4 ,it is well to study this illustration carefully so that you will understand just how all the parts are arranged4 99,the ,base99 is illustrated in ,figure #ea4 ,it is made of a piece of hardwood1 seven inches long1 three and one-half inches wide1 and one-half an inch thick4 99,the ,electromagnets99 will largely determine the dimensions of the rest of the engine4 ,the magnets shown in ,figure #eb are made of three-eighths inch round iron two and one-half inches long1 provided with two fibre washers one and one-eighths inches in diameter4 ,on end of each of the steel cores is drilled and tapped to received an #h-cb screw4 ,the experimenter may possibly be able to secure some old magnet cores fitted with fibre heads from an old telephone bell or ringer as they are sometimes called4 ,a suitable bolt may be made to serve the purpose by cutting it off to the right dimensions with a hack saw4 ,if a drill and tap are not available for drilling and tapping the end so that the core can be properly mounted in the frame of the engine1 it is possible1 to use the threaded portion of a bolt to good advantage1 by the exercise of a little ingenuity4 ,the hole in the frame should then be made larger so that the end of the bolt will slip through1 instead of an #h-cb screw and the core clamped in position by a nut on each side4 ,the fibre washers are spaced two and one-sixteenth inches apart4 ,the space in between should be wound full of ,no4 #ah ,b4 ,s4 ,gauge cotton covered magnet wire4 ,before winding in the wire1 cover the core with a layer of paper so that the wire does not touch the metal4 ,the ends of the wire should be led out through small holes in the fibre heads4 ,illustration3 ,,fig4 #eb4--;,details showing the size of the ,magnet ,bobbin4 ,it is not absolutely necessary to use ,no4 #ah ,b4 4,s4 ,gauge wire in winding the magnets1 but it is the size which will give the best results on the average battery4 ,if you use larger wire1 the engine will require more current from the battery4 ,if you use finer wire1 a battery of higher voltage will be necessary4 ,the current consumption will1 however be less4 ,the electromagnets are mounted in the frame of the engine by means of two screws passing through the holes ,e and ,d4 ,the details of the frame are illustrated in figure #ec4 ,it is made of a strip of wrought iron or cold rolled steel1 five and five-eighths inches long1 an inch and one-eighth wide and one-eighth inch thick4 ,the material for making this part of the engine and also the bearings can best be obtained at some blacksmith shop or hardware store4 ,heavy galvanized iron can be used but it is not usually thick enough1 and it may be necessary to use two thicknesses4 ,the ends of the strip are rounded and bent at right angles so as to form a ,u-shaped piece with sides one and three-quarters inches high4 ,the holes1 ,d and ,e1 should be large enough to pass an #h-cb screw4 ,the holes1 ,a1 ,b and ,c should be about one-eighth of an inch in diameter4 ,they are used to pass the screws which hold the frame of the engine to the wooden base4 ,illustration3 ,,fig4 #ec4--,the ,frame which supports the ,electromagnets4 99,the ,bearings99 are shown in ,figure #ed4 ,they are made ,u-shaped and are out of a strip of iron or steel in the same manner as the frame of the engine1 but are three-quarters of an inch wide instead of an inch and one-eighth4 ,the dimensions will be understood best by referring to the drawing4 ,the #c_/cb inch holes near the top of each side are the bearing holes for the end of the shaft4 ,the one-eighth inch holes just below are used to fasten the brush holder in position4 ,the holes in the bottom serve to fasten the bearings to the base4 ,illustration3 ,,fig4 #ed4--,the ,main ,bearings4 99,the ,shaft99 will probably prove the most difficult part of the engine to make properly4 ,the details are given in ,figure #ee4 ,it is made of a piece of one-eighth inch steel rod bent so that a crank is formed in the middle4 ,the crank should be bent so that it has a throw of one-half an inch1 that is1 offset one-quarter of an inch so that the connecting rod moves back and forth a distance of one-half an inch4 ,the finished shaft should be three inches long4 ,the piece of steel used should be longer than this and so that it can be cut off to exact dimensions after the shaft is finished4 ,a second crank should be bent in one end of this so as to form an offset contact for the brushes4 ,this second crank will have to be at right angles to the first one and should be much smaller4 ,the ends of the shaft are turned or filed down to a diameter of three-thirty-seconds of an inch for a distance of about the same amount so that they will fit in the bearing holes and turn freely1 but not allow the shaft to slip through4 ,the work of making the shaft will require a small vise1 a light hammer1 files and a couple of pliers4 ,one pair of pliers should be of the round nosed type and the other a pair of ordinary square jawed side cutters4 ,it may require two or three attempts before a perfect shaft is secured4 ,when finished1 it should be perfectly true and turn freely in the bearings4 ,the bearings can be adjusted slightly by bending1 so that the shaft will fit in the holes and be free1 but yet not loose enough to slip out4 99,the ,armature99 is a strip of soft iron1 two and one-eighth inches long1 seven-sixteenths of an inch wide and three-sixteenths of an inch thick4 ,a one-sixteenth inch slot1 three-eighths of an inch long is cut in one end4 ,a one-sixteenth inch hole is drilled through from one side to the other1 one-eighth of an inch from each end4 ,the hole which passes through the slot is used tu pass the pin which pivots the armature to the connecting rod4 ,the other hole is used to mount the armature in its bearing4 ,the armature bearing is a small edition of the one which is used to support the engine shaft4 ,the details and the dimensions are given in the lower left hand side of ,figure #ef4 ,the armature is shown in the center of the same illustration4 ,the connecting rod is illustrated at the right4 ,this is made from a strip of three-sixty-fourths inch brass1 three sixteenths of an inch wide and one and five-eighths inches long4 ,the one-eighth inch hole should be drilled close to one end and a one-sixteenth inch hole close to the other4 ,illustration3 ,,fig4 #ee4--,the ,shaft4 99,the ,brushes99 are two strips of thin phosphor bronze sheet1 two and three-sixteenths inches long and nine thirty-seconds of an inch wide4 ,they are illustrated in ,figure #eg4 ,the block upon which they are mounted is hard fibre4 ,it is one and five-eighths inches long and three-eighths of an inch square4 ,it may be possible to secure a flywheel for the engine from some old toy4 ,it should be about three and one-half inches in diameter4 ,a flywheel can be made out of sheet iron or steel by following the suggestion in ,figure #eh1 which shows a wheel cut out of one-eighth inch sheet steel4 ,it is given the appearance of having spokes by boring six three-quarter inch holes through the face as shown4 ,the hole in the center of the wheel should be one-eighth of an inch in diameter4 ,the wheel is slipped over the shaft and fastened in position by soldering4 ,the parts are now all ready to assemble into the complete engine4 ,mount the electromagnets in the frame and fasten the frame down to the wooden base so that one end of the frame comes practically flush with the left hand edge of the base4 ,fasten the bearing across the frame at right angles by a screw passing through the center hole in the bottom of the bearing through the hole ,a and into the base4 ,the bottom of the bearing should be bent slightly so as to straddle the frame4 ,the bearing should be secured and prevented from turning or twisting by two screws passed through the other two holes in the bottom ,use round headed wood screws in mounting the bearing and the frame4 ,illustration3 ,,fig4 #ef4--,showing the ,armature1 ,armature ,bearing and the ,connection ,rod4 ,the armature bearing should be mounted on the frame directly between the two electromagnets4 ,then place the armature in position by slipping a piece of one-sixteenth inch brass rod through the bearing holes and the hole in the lower part of the armature4 ,solder the flywheel in position on the shaft and snap the latter into the bearings4 ,adjust the bearings so that the shaft will turn freely4 ,the connecting rod should be slipped over the shaft before it is placed in the bearings4 ,fasten the other end of the connecting rod to the armature by means of a piece of one-sixteenth inch brass rod which passed through the small holes bored for that purpose4 ,when the flywheel is spun with the fingers1 the armature should move back and forth between the two electromagnets and almost1 but not quite1 touch the two magnet poles4 ,illustration3 ,,fig4 #eg4--;,details of the ,brushes and ,brush ,holder4 ,all the moving parts should be fitted firmly together but be free enough so there is no unnecessary friction and so that the engine will continue to run for a few seconds when the flywheel is spun with the fingers4 ,the brushes1 supported on their fibre blocks1 should be mounted on the bearing by means of two screws passing through the holes in the bearing into the block4 ,the position of the brushes should be such that the shaft passes between the two upper ends but does not touch them unless the small contact crank mentioned above is in proper position to do so4 ,the proper adjustment of the brushes so that they will make contact with the shaft at the proper moment will largely determine the speed and power which the finished engine will develop4 ,illustration3 ,,fig4 #eh4--,showing how a ,flywheel may be made out of sheet iron4 ,two binding posts should be mounted on the right hand end of the base so that the engine can be easily connected to a battery4 ,connect one terminal of the right hand electromagnet to one of the binding posts4 ,run the other terminal of the electromagnet to the brush on the opposite side of the shaft4 ,connect one terminal of the left hand electromagnet to the other binding post and run the other terminal to the brush on the opposite side of the shaft4 ,save for a few minor adjustments1 the engine is now ready to run4 ,connect two or three cells of dry battery to the two binding posts and turn the flywheel so that it moves from right to left across the top4 ,just as the crank passes dead center and the armature starts to move back away from the left hand magnet1 the small contact crank on the shaft should touch the left hand brush and send the current through the right hand magnet4 ,this will draw the armature over to the right4 ,just before the armature gets all the way over to the right1 the contact should break connection with the left hand brush and interrupt the current so that the inertia of the flywheel will cause it to keep moving and the armature to start to move over toward the left hand magnet at which point the contact on the shaft should commence to bear against the right hand brush1 thus throwing the left hand magnet into circuit and drawing the armature over to that side4 ,if the brushes and the cranks are in proper relation to each other the engine will continue to repeat this operation and gradually gain speed until it is running at a good rate4 ,the appearance of the engine can be improved by painting the metal parts black and the flywheel red4 ,the magnets can be wrapped with a piece of bright red cloth to protect the wire against injury and also lend attraction to its appearance in this way4 ,,chapter ,,iv ,,small ,,power ,,motors ,in order for a motor to develop any appreciable amount of power it must be much larger than any of those which have been described in these pages so far1 and must be constructed in a most painstaking manner4 ,it will be necessary to use a great deal more iron in the field and armature and also to make the space between them as small as possible4 ,a motor having a small separation between the field poles and the armature will develop more power than one having a greater separation4 ,illustration3 ,,fig4 #ei4--;,a ,vertical ,battery ,power ,motor4 ,the most efficient types of small power motors have laminated field and armature frames1 that is1 they are built up of a large number of thin metal punchings4 ,the amateur experimenter who has limited facilities for carrying out his work would find it difficult to make parts of this sort to good advantage and so the motors described here have been designed with cast iron armatures and field frames4 ,those who wish to secure a set of castings from their own patterns can possibly save part of the expense if they do not consider the extra labor of first making the patterns4 ,two types of motors are described1 one vertical and the other horizontal4 ,both are intended to operate on a battery current of #c-f volts and if carefully built will deliver a surprising amount of power4 ,illustration3 ,,fig4 #fj4--;,details of the ,field ,frame of the ,vertical ,motor4 ,a ,,vertical ,,power ,,motor 99,the ,field ,frame99 is shown in detail in ,figure #fj4 ,the exact shape and dimensions are best understood by a careful examination of the drawing4 ,the pattern for the field may be made of the same shape and practically the same size as indicated for the finished casting because the rapping or jarring which the pattern will receive in the foundry in order to free it from the sand mould will enlarge the mould sufficiently in a casting of small size to make up for any shrinkage which takes place upon the cooling of the iron4 ,the only exception to this is in the tunnel where the armature rotates4 ,this should measure one and three-quarter inches in diameter when finished and should be slightly smaller in the rough casting so that there is enough material to allow for truing and bringing to equal size4 99,the ,armature99 may be of two types1 three pole or six pole4 ,the three-pole armature is the simpler1 but the six-pole type is the smoother running and gives the steadier power4 ,the details and dimensions are shown in ,figures #fa and #fb4 ,one of the armatures should be selected and a pattern built4 ,illustration3 ,,fig4 #fa4--,three-pole ,armature4 ,after the patterns are finished they should be given a coat of shellac and carefully rubbed with fine sandpaper so that they are perfectly smooth4 ,otherwise the sand is liable to stick in moulding and produce an imperfect casting4 ,castings may be obtained from any foundry which is equipped to make grey iron castings4 ,they should be as soft as possible4 ,the cost will depend upon the quantity which are ordered4 ,if only one set is required1 the charge will probably be based upon the time required for making the moulds but if several sets are ordered the price may be based upon the weight4 ,after the castings have been received from the foundry1 the first operation is to carefully remove all rough spots and burrs with a file4 ,those who have a lathe or large drill press can easily finish the tunnel by turning or reaming4 ,in the absence of these facilities1 hand filing can be made to suffice1 if carefully done4 ,the holes marked ,,bbbb should be drilled with a ,no4 #bi drill and tapped #h-cb4 ,these holes must be very carefully located because they serve to fasten the bearings4 ,each hole should be exactly opposite the other1 two and five-sixteenth inches apart and on a line passing exactly through the centre of the tunnel4 ,the holes1 ,,pp and ,,ss1 are three-sixteenths of an inch in diameter4 ,the former support the ,binding ,posts and the latter pass the screws which fasten the motor to the wooden base4 ,illustration3 ,,fig4 #fb4--,six-pole ,armature4 ,the armature1 in the case of either the six or three pole type1 has a three-sixteenth inch hole drilled along the axis to accommodate a steel shaft of the same diameter4 ,the armature casting should be accurately turned to a diameter of one and twenty-three thirty-seconds of an inch so that it will revolve in the tunnel without touching the field but still be very close to it4 ,two holes bored through one of the pole pieces at right angles to the shaft with a ,no4 #cg drill and threaded with a #f-cb tap will allow the armature to be clamped tightly to the shaft with two headless set screws4 99,the ,field ,winding99 consists of ,no4 #af double cotton insulated wire4 ,before the winding is put on1 the core should be insulated with one or two layers of shellaced paper4 ,two circular pieces of shellaced paper should be placed against the flanges at the end of the core1 so that the winding space is thoroughly insulated and there is no liability of the wire touching the iron at any point4 ,the wire should be wound in smooth even layers4 ,the winding space is completely filled4 ,the outside layer may be finished by a coat of shellac4 ,the three-pole armature is much easier to wind than the six pole type4 ,the wire used should be ,no4 #bd ,b4 ,s4 ,gauge1 double cotton covered4 ,before the wire is wound on1 cover the winding space with shellaced paper so that the wire will not touch the iron at any point4 ,each coil should be wound in the same direction as the others starting at the same end and as close as possible to the inside4 ,illustration3 ,,fig4 #fc4--,showing how the ,coils on a ,three-pole ,armature are connected to the ,commutator4 ,the outside end of each coil should be connected to the inside of the next coil as shown in ,figure #fc4 ,the diagram indicates only one layer of wire in each coil for the sake of clearness4 ,the winding upon the armature shown in ,figure #fd is divided into six coils4 ,each coil consists of as many turns as possible of ,no4 #bd ,b4 ,s4 ,gauge1 cotton covered wire to fill the space completely and all coils are wound in the same direction4 ,the illustrations show the various stages of the bindings with the two1 four and six coils in place4 ,the winding spaces on the armature should be carefully insulated with shellaced paper before the coils are placed in position4 ,after the winding has been finished the next step is to make the shaft and commutator4 ,the shaft is a piece of three-sixteenths steel1 three and one-quarter inches long4 ,the shaft passes through the centre of the armature and is locked-in position by the two set screws4 99,the ,commutator99 is probably one of the most difficult parts of the motor to make4 ,it consists of three circular brass sections insulated from one another on a fibre bushing4 ,the fibre bushing is a hollow cylinder1 five-sixteenths of an inch in diameter and seventeen thirty-seconds of an inch long4 ,the bushing should force tightly on the shaft4 ,the segments are make by turning a piece of three-quarter inch brass rod in a lathe until it is one-half an inch in diameter for a distance of about seven-sixteenths of an inch4 ,a five-sixteenths inch hole should be bored through the center so that it will fit tightly upon the fibre bushing4 ,illustration3 ,,fig4 #fd4--,showing how the ,coils on a ,six-pole ,armature are arranged and connected4 ,then cut the brass off one-half inch from the end so that it leaves a flange at one end1 three-quarters of an inch in diameter4 ,saw it lengthwise into three equal parts and mount it upon the fibre bushing with a small strip of mica between each two sections to fill in the space made by the saw cuts4 ,the sections are held together by a fibre ring1 three quarters of an inch in diameter outside and one-half an inch in diameter inside4 ,the ring should fit very tightly over the commutator and be forced down flush against the shoulder4 ,after the ring is in position1 file any mica which may project out of the slots down even with the surface of the segments and force the commutator onto the shaft with the shoulder against the armature4 ,the commutator must fit very tightly so that there is not any possibility of moving it after it is in position4 ,illustration3 ,,fig4 #fe4--;,details of the ,commutator4 ,the sections should bear a certain relative position to the armature windings4 ,the diagrams in ,figures #fc and #fd show the proper position for the three and six pole armature respectively4 ,the coils are connected to the commutator by soldering the terminals to the shoulder on each segment4 ,this work should be very carefully done so as to insure a neat job and connection of the proper terminal to the proper section4 ,illustration3 ,,fig4 #ff4--;,details of the ,bearings1 ,shaft1 and ,pulley4 ,,connections ,,for ,,the ,,three ,,pole ,,armature ,the inside terminal of coil ,a and the outside terminal of coil ,b should be connected to ,section #a1 the inside terminal of coil ,b and the outside terminal of coil ,c should be connected to ,section #c1 the inside terminal of coil ,c1 and the outside terminal of coil ,a should be connected to ,section #b4 ,,connections ,,for ,,the ,,six-,,pole ,,armature ,the inside terminal of coil ,a and the inside terminal of coil ,b should be connected to section #b1 the outside terminal of coil ,c and the outside terminal of coil ,d should be connected to ,section #c1 the outside terminal of coil ,e and the outside terminal of coil ,f should be connected to ,section #a1 the outside terminal of coil ,a and the inside terminal of coil ,c should be connected to ,section #a1 the inside terminal of coil ,d and the inside terminal of coil ,e should be connected to ,section #b1 the inside terminal of coil ,f and the outside terminal of coil ,d should be connected to ,section #c4 ,illustration3 ,,fig4 #fg4--,the ,brushes and ,brush ,holder4 ,the wires leading from the coils to the commutator should be just as short as it is possible to make them and after being soldered should be bound down tightly with linen thread or string4 ,the bearings are both cast from brass4 ,the details are shown in ,figure #ff ,it will be necessary to make up wooden patterns and send them to a foundry4 ,the location of the holes can be ascertained from the illustration4 ,illustration3 ,,fig4 #fh4--;,details of the ,field ,frame for the ,horizontal ,power ,motor4 ,each of the brushes consists of a piece of strip copper1 one-quarter of an inch wide and one and three-eighths inches long mounted in a brush holder made of one-quarter inch brass rod4 ,the brush holder is one inch long and is turned down to a diameter of one-eighth of an inch at one end for a distance of nine-sixteenths of an inch and then threaded with a #f-cb die4 ,the opposite end is slotted to receive the brush4 ,the threaded portion of the holder is slipped through the holes1 ,b and ,b1 in the bearing and prevented from making contact with the latter by a fibre bushing4 ,illustration3 ,,fig4 #fi4--;,front view of the ,field ,frame4 ,illustration3 ,,fig4 #gj4--,the ,field ,magnet ,bobbin4 ,a fibre washer should also be slipped over the holder on each side of the bearing4 ,two hexagonal nuts are placed on the threaded stem4 ,one serves to clamp the holder in position and the other to hold the wire used to make connection with the brush4 ,the right hand brush should bear against the under side of the commutator and the left hand brush against the upper side4 ,after the armature has been assembled in the bearings and mounted on the field frame it should revolve freely without friction and without any possibility of its striking against the field poles4 ,the binding posts are mounted in the holes1 ,,pp in the lower parts of the field frame4 ,they are insulated by two fibre or paper busings4 ,the left hand binding post is connected to the inside terminal of the field winding4 ,the outside terminal of the field winding is connected to the left hand binding post4 ,the right hand binding post is connected to the right hand brush4 ,the base of the motor is a wooden block of suitable size4 ,illustration3 ,,fig4 #ga4--;,details of the ,shaft1 ,rocker ,arm1 ,bearing and ,pulley4 ,the motor is of the series type because all the current flows through both the field and armature4 ,a current of #b to #f volts will operate the motor4 ,the pulley or gear required in order that the motor may be used as a source of power will depend upon the work for which the motor is to be employed4 ,a small grooved pulley such as as that shown in ,figure #fc may be fastened to the shaft with a set screw and will prove most useful for general purposes4 ,a ,,horizontal ,,power ,,motor4 ,the horizontal motor does not differ very materially from the vertical one just described4 ,the field frame is1 however1 made in two pieces1 and the bearings are cast directly on the frame4 ,the details and dimensions are given in ,figures #fh1 #fi and #gj4 ,illustration3 ,,fig4 #gb4--,rear view of the completed ,horizontal ,motor4 ,the field winding consists of six layers of ,no4 #ah ,b4 ,s4 ,gauge double cotton-covered wire wound on a spool or bobbin4 ,the core of the bobbin consists of a piece of five-eighths round steel or iron rod1 two and seven-sixteenths inches long4 ,two circular fibre heads1 one-eighth of an inch thick and one and one-half inches in diameter are mounted on the core one-half an inch from one end and fifteen-sixteenths of an inch apart4 ,the ends of the core are set in the holes1 ,c1 ,c1 in the two parts of the field frame and held in position by two set screws threading into the holes ,s and ,s4 ,either the three-pole or the six-pole armature may be used4 ,the commutator and brushes are identical with those used in the vertical type of motor4 ,the shaft is three-sixteenths of an inch in diameter and four inches long4 ,the brushes are mounted upon a brush arm which is shown in detail in ,figure #fc4 ,this is made of three-sixteenths inch sheet brass4 ,the brushes must be insulated from the arm by fibre washers and bushings in the same manner as they were from the bearings on the vertical motor4 ,illustration3 ,,fig4 #gc4--,side view of the ,horizontal ,motor4 ,the holes in the bearings on the field frame are drilled out three-eighths of an inch in diameter and then brushed with a piece of three-eighths inch brass rod five-sixteenths of an inch in diameter having a three-sixteenths inch hole through the center4 ,any of the ,following ,practical ,books 99will be sent ,at ,once1 ,post-paid on receipt of price499 ,there is very little danger of losing currency in a letter if the following directions are observed3 ,cut a circular hole the diameter of the coin in a piece of cardboard1 of sufficient size to fit closely in the envelope4 ,the cardboard should be no thicker than the coin4 ,insert the coin in the hole and paste a piece of paper on both sides of the cardboard to prevent the coin from falling out4 ,,cole ,,morgan ,publishers of the ,arts and ,sciences ,series ,p4,o4 ,box #dgc1 ,city ,hall ,station ,new ,york1 ,n4 ,y4 99,experimental ,wireless ,construction99 99,,eighty-,,six ,,pages ,,ninety-,,three ,,illustrations99 99,only #cj ,cents1 ,postpaid99 ,here at last is the book which every young experimenter interested in constructing his own wireless apparatus has been looking for4 ,a book which tells how to build apparatus which anyone would be proud to own4 ,it is a more advanced book than ,wireless ,construction and ,installation for ,beginners1 and describes apparatus which is much more elaborate and sensitive4 ,the instruments have all been the subject of considerable experimental work and study4 ,all the apparatus has been put to practical test and carefully improved by clever experts4 ,by purchasing this book you get the benefit of vast knowledge and experience and are enabled to build far better instruments than by following your own designs and haphazard methods4 99,partial ,contents99 ,chapter ,i4--,,the ,,aerial4 ,chapter ,,ii4--,,spark ,,coils4 ,chapter ,,iii4--,,transmitting ,,apparatus ,,and ,,its ,,construction4 ,chapter ,,iv4--,,the ,,receiving ,,apparatus ,,and ,,its ,,construction4 ,chapter ,v4--,,arrangement ,,and ,,operation ,,of ,,the ,,apparatus4 ,,complete ,,details ,,are ,,given ,,with ,,working ,,drawings4 99,sent anywhere postpaid for #cj ,cents99 99,the ,boy ,electrician99 ,practical ,plans for ,electrical ,toys and ,apparatus1 with an ,explanation of the ,principles of ,everyday ,electricity4 99,by ,,alfred ,p4 ,,morgan499 ,author of ,wireless ,telegraph ,construction for ,amateurs and ,wireless ,telegraphy and ,telephony1 etc4 99,with full-page ,illustrations and #cbd ,working ,drawings and ,diagrams99 99by the author4 #hvo41 ,cloth1 ,net ,price1 #b4be499 ,this is the age of electricity4 ,the most fascinating of all books for a boy must therefore be one dealing with the mystery of this ancient force and modern wonder1 even a mere list of whose services is impossible4 ,the best qualified of experts to instruct boys1 ,alfred ,p4 ,morgan1 has in a book far superior to any other of its kind told not only how to make all kinds of motors1 telegraphs1 telephones1 batteries1 etc41 and to do so economically1 but has explained the principles upon which these depend for operation1 and how the same thing is done in the every-day world be well presented and so attractive is this really great book that it will be an education for any bright boy to have it1 as well as the best kind of a moral safeguard1 by leaving no time or thought for evil1 and a means of future benefit beyond the power of any one to reckon4 ,glancing over the pages of this book1 one cannot but be impressed by the excellent illustrations1 clearness of expression and the large number of subjects that are covered4 ,it is beyond doubt the best book in this line that has ever been written or published4 ,it is a book that will delight every boy who has a leaning towards electrical experiments4 ,the author writes in a clear and chatty style and while he has a thorough technical knowledge of his subject he has succeeded in treating it in a simple manner so that it is readily intelligible to his young readers4 99,among the ,chapter ,headings and ,contents are399 ,magnets and ,magnetism--,static ,electricity--,static ,electric ,machines--,cells and ,batteries--,electro-,magnetism and ,magnetic ,induction--,electrical ,units--,electrical ,appurtenances--,electrical ,measuring ,instruments--,bells1 ,alarms and ,annunciators--,electric ,telegraphs--,microphones and ,telephones--,induction ,coils--,transformers--,wireless ,telegraphy--,wireless ,telephony--,electric ,motors--,dynamos--,an ,electric ,railway--,miniature ,lighting--,miscellaneous ,electrical ,apparatus4 99,,read ,,what ,,has ,,been ,,said ,,of ,,it499 ,even a casual glance through the many pages of the book does not fail to emphasize the fact that ,mr4 ,alfred ,p4 ,morgan has indeed succeeded well in giving the juvenile electricians a work that has long been sought4--,popular ,electricity4 ,we have no hesitation in commending the book to the attention of the juvenile audience for which it is intended4--,boston ,post4 ,a great book for enterprising boys4 ,bright boys will highly appreciate it and feel like thanking the wideawake publishers for putting such a reliable and interesting work in the field4--,new ,haven ,journal4 ,the book covers the subject of electricity thoroughly in all its phases and is a splendid acquisition to any boy's library4--,detroit ,times4 ,in this age of electricity a book like the present one is both fascinating and valuable especially to boys4 ,the book is attractive with its many illustrations and will prove of much educational value for any bright boy4--,zion's ,herald4 ,this is an admirably complete and explicit handbook for young boys who fall under the spell of tinkering with electrical apparatus4--,boston ,transcript4 ,well presented and attractive this book will be a source of great benefit and delight for any bright boy4--,new ,orleans ,times-,picayune4 99,price1 #b4be ,postpaid99 ,,countless ,,other ,,magazines1 ,,newspapers ,,and ,,libraries ,,have ,,endorsed ,,this ,,great ,,book4 ,,send ,,for ,a ,,copy ,,now4 99,if you are interested in this great book1 write for our #h-page special99 99descriptive circular499 ,wireless ,telegraphy and ,telephony ,simply ,explained ,by ,,alfred ,p4 ,,morgan4 99,a ,,new ,,book by the author of ,wireless ,telegraph ,construction for ,amateurs499 ,this is undoubtedly one of the most complete and comprehensive treatises on the subject ever published1 and a close study of its pages will enable one to master all the details of the wireless transmission of messages4 ,the author has tilled a long-felt want and has succeeded in furnishing a lucid1 comprehensible explanation in simple language of the theory and practice of wireless telegraphy and telephony4 ,the book treats the subject from an entirely new standpoint4 ,several very novel and original ideas have been carried out in its making4 ,it is well illustrated by over one hundred and fifty interesting photographs and drawings44 ,all diagrams have been made' in perspective showing the instruments as they actually appear in practice4 ,the drawings are carefully keyed and labeled4 ,many of the photographs are accompanied by phantom drawings which reveal the name and purpose of each part4 ,it is a book which the wireless experimenter cannot afford to be without4 ,it will prove even more valuable to the layman4 99,among the contents are3 ,introductory4 ,wireless ,transmission and ,reception4 ,the ,ether4 ,electrical ,oscillations4 ,electro magnetic ,waves4 ,the ,means for ,radiating and ,intercepting ,electric ,waves4 ,aerial ,systems4 ,earth ,connection4 ,the ,transmitting ,apparatus4 ,current ,supply4 ,spark ,coils and ,transformers4 ,condensers4 ,helixes4 ,spark ,gaps4 ,anchor ,gaps4 ,aerial ,switches1 ,etc4 ,the ,receiving ,apparatus4 ,detectors1 ,etc4 ,tuning ,coils and ,loose ,couplers4 ,variable ,condensers4 ,tuning and ,coupling4 ,directive ,wave ,telegraphy4 ,the ,dignity of ,wireless4 ,its ,applications and ,service4 ,wireless in the ,army and ,navy4 ,wireless on an ,aeroplane4 ,how a ,message is ,sent and ,received4 ,the ,wireless ,telephone4 ,the ,ear4 ,how ,we ,hear4 ,sound and ,sound ,waves4 ,the ,vocal ,cords4 ,the ,structure of ,speech4 ,the ,telephone ,transmitter and ,receiver4 ,the ,photophone4 ,the ,thermophone4 ,the ,selenium ,cell499 99,handsomely ,bound in ,cloth with ,embossed ,cover4 7,postpaid1 #a4jj799 ,build ,your ,own ,wireless ,instruments ,complete ,up-to-the-,minute ,authentic ,practical ,,wireless ,,telegraph ,,construction ,,for ,,amateurs ,by ,,alfred ,,powell ,,morgan #c;d ,,edition #bbj ,pages #afc ,illustrations 99,price1 #a4ej1 ,postpaid99 99,handsomely ,bound in ,silk ,cloth99 ,thoroughly up to date and unusually complete4 ,given in minute detail1 full directions for constructing wireless apparatus and various outfits capable of receiving from #ajj to #a1ejj miles and transmitting #c to #ajj miles4 ,also clearly explains the purpose and action of each instrument4 ,directions for ,operating and ,adjusting1 etc4 99,a ,,splendid ,,treatise ,,of ,,wireless ,,along ,,constructive ,,lines99 ,price1 #a4ej1 ,postpaid ,the value of this book has been greatly increased by the addition of much new subject matter and many illustrations of recent interest4 ,the new text explains fully how to build the most recent forms of ,quenched ,gaps1 ,rotary ,gaps1 ,dough-,nut ,tuners1 ,kick-back ,preventers1 ,audion ,detectors and numerous other instruments1 accompanied by dimensioned working drawings ,several very interesting and instructive photographs have been included4 99,i4--,introduction4 ,,ii4 ,the ,apparatus4 ,,iii4--,aerials and ,earth ,connections4 ,,iv4--,induction ,coils4 ,v4--,interrupters4 ,,vi4--,transformers4 ,,vii4--,oscillation ,condensers and ,leyden ,jars4 ,,viii4--,spark ,gaps or ,oscillators4 ,,ix4--,transmitting ,helixes ,x4--,keys4 ,,xi4--,aerial ,switches and ,anchor ,gaps4 ,,xii4--,hot ,wire ,ammeter4 ,,xiii4--,oscillation ,detectors4 ,,xiv4--,tuning ,coils and ,tuning ,transformers4 ,,xv4--,receiving ,condensers4 ,,xvi4--,telephone ,receivers and ,headbands4 ,,xvii4--,operation4 ,,xviii4--,the ,amateur and the ,wireless ,law4 ,how to ,secure a ,license4 ,oscillation ,helix4 ,quenched ,spark ,gap4 ,rotary ,gaps4 ,kick-,back4 ,the ,variometer4 ,new ,crystal ,detectors4 ,the ,audion4--,appendix499 99,,endorsed ,,by ,,wireless ,,clubs ,,throughout ,,the ,,country ,,as ,,being ,,the ,,most ,,practical ,,book ,,published ,,on ,,wireless499 99,,if ,,you ,,are ,,interested ,,in ,,wireless ,,you ,,need ,,this ,,book99 99,,lessons ,,in ,,wireless ,,telegraphy99 7,,written ,,so ,,that ,,you ,,can ,,understand ,,them7 ,our new book contains a systematic elementary course in the principles of ,wireless ,telegraphy and the electrical laws upon which it depends4 ,it contains more reliable and practical information than any other book of its kind4 99,,if ,,you ,,own ,a ,,wireless ,,outfit99 it will give you a thorough grounding in the principles and care of the efficiency of your apparatus4 99,,if ,,you ,,intend ,,purchasing ,,or ,,operating ,,wireless ,,telegraph ,,apparatus99 you could not desire a more complete or concise explanation of matters it is essential to understand4 99,,if ,,you ,,are ,a ,,layman99 the book will prove valuable and interesting4 ,it is something that you can well afford to read for it will give you a clear conception of one of the greatest wonders of the age4 99,price1 #cj ,cents1 ,postpaid499 ,the book is divided into thirty lessons1 each lesson dealing with a separate subject and following in a logical order so that repetition and possibility of confusion are completely avoided4 ,it is profusely illustrated with perspective drawings and diagrams1 each being carefully keyed so that parts may be readily discerned4 ,it not alone describes the actual workings and construction of the instruments that go to make up a wireless station in sufficient detail to prove of great value to the experienced student but treats the subject in such a manner that even the beginner will have no trouble to clearly grasp the matter4 ,among the lists of contents may be mentioned a careful discussion and explanation of such subjects as the why and the wherefore of ,magnetism1 ,magnetic ,induction1 ,primary ,cells1 ,storage ,batteries1 the ,dynamo1 the ,alternator1 the ,motor ,generator1 the ,induction ,coil1 the ,transformer1 the ,condenser1 ,volts1 ,amperes1 ,watts1 ,coulombs1 ,ohm's ,law1 ,electric ,waves1 the ,ether1 ,oscillations1 the ,aerial1 ,spark ,gaps1 ,quenched ,gaps1 ,rotary ,gaps1 ,helixes1 ,coupling1 ,tuning1 ,detectors1 ,tuning ,coils1 ,loose ,couplers1 ,variometers1 ,condensers1 ,hot ,wire ,ammeters1 ,circuits and ,diagrams1 etc41 etc41 etc4 ,each subject is discussed in detail and in all its branches4 ,for instance1 the lesson dealing with aerials describes vertical aerials1 pyramid aerials1 flat top aerials1 umbrella aerials1 loop aerials1 etc41 and peculiarities or advantages4 ,the lesson on detectors deals with ,electrolytic1 ,perikon1 ,silicon1 ,pyron1 ,carborundum1 ,magnetic and ,audion ,detectors1 etc4 ,the lesson on the theory and arrangement of circuits will be found invaluable4 99,,this ,,is ,,the ,,book ,,that ,,you ,,have ,,been ,,looking ,,for499 ,home ,made ,electrical ,apparatus ,three of the most popular books ever published1 filled with just the sort of information you have been looking for4 ,each volume is printed on heavy paper and contains #gb pages and over #fj illustrations and working drawings for making every sort of electrical apparatus1 all of which has actually been built by the author4 ,written so that you can completely understand them4 ,,volume ,i1 ,no4 #g--hj ,pages--#ff ,illustrations ,chapter ,i--,,static ,,electrical ,,apparatus--,static ,electricity4 ,how to ,build a ,wimshurst ,machine4 ,experiments with ,static ,electrical ,apparatus4 ,chapter ,,ii--,,cells ,,and ,,batteries4 ,chapter ,,iii--,,how ,,to ,,reduce ,,the #aaj ,,volt ,d4 ,c4 ,,or ,a4 ,c4 ,,to ,a ,,lower ,,voltage ,,for ,,experimental ,,purposes4 ,chapter ,,iv--,,how ,,an ,,alternating ,,current ,,may ,,be ,,changed ,,into ,,direct ,,current ,,by ,,means ,,of ,,an ,,electrolytic ,,rectifier4 ,chapter ,v--,,how ,,to ,,build ,a ,,step-,,down ,,transformer ,,for ,,reducing ,,the #aaj ,,volt ,a4 ,c4 ,,for ,,experimental ,,purposes4 ,,volume ,,ii1 ,no4 #h--gb ,pages--#ee ,illustrations ,chapter ,,vi--,,electrical ,,measuring ,,instruments4 ,galvanometers1 ,ammeters1 ,voltmeters1 etc4 ,chapter ,,vii--,,current ,,control ,,devices4 ,how to ,make a ,pole ,changing ,switch or ,current ,reverser4 ,how to ,reverse ,small ,motors4 ,battery ,rheostats4 ,chapter ,,viii--,,how ,,to ,,make ,a ,,telegraph ,,key ,,and ,,sounder4 ,how to ,install a ,telegraph ,line and ,learn to ,operate4 ,learning the ,morse ,code4 ,chapter ,,ix--,,how ,,to ,,make ,,and ,,install ,a ,,telephone4 ,chapter ,x--,,medical ,,coils ,,and ,,shocking ,,coils4 ,chapter ,,xi--,,the ,,construction ,,of ,,spark ,,coils4 ,a one-quarter inch ,coil1 a one-half inch ,coil1 a one inch ,coil4 ,experiments with ,spark ,coils4 ,,volume ,,iii1 ,no4 #i--hj ,pages--#gc ,illustrations ,chapter ,,xii--,,how ,,to ,,make ,a ,,dynamo-,,motor4 ,chapter ,,xiii--,,how ,,to ,,make ,a ,,toy ,,battery ,,motor4 ,chapter ,,xiv--,,how ,,to ,,build ,,an ,,electric ,,engine4 ,chapter ,,xv--,,miniature ,,battery ,,lamp ,,lighting4 ,chapter ,,xvi--,,coherer ,,outfits ,,for ,,wireless ,,telegraphy4 ,chapter ,,xvii--,,how ,,to ,,build ,a ,,tesla ,,high ,,frequency ,,coil4 ,experiments with ,high ,frequency ,currents4 ,chapter ,,xviii--,,an ,,experimental ,,wireless ,,telephone4 ,chapter ,,xix--,,miscellaneous ,,apparatus4 ,electrolysis of ,water4 ,electro-,plating4 ,electricity from ,heat4 ,a ,handy ,light4 ,an ,experimental ,arc ,lamp4 ,a ,magnetic ,diver4 ,magnetic ,fish4 ,a ,magnetic ,clown4 ,an ,electric ,breeze4 ,a ,static ,motor4 99,price ,postpaid1 #cj cents per volume99 ,all three volumes can be supplied bound together with handsome cloth cover for #a4be postpaid4 ,vacuum ,tubes in ,wireless ,communication ,by ,,elmer ,e4 ,,bucher 99,the only ,text ,book on the market devoted solely to the various applications of the ,oscillation ,valve499 ,an elementary text book for students1 operators1 experimenters and engineers4 ,naval wireless men find this book especially helpful4 ,tells in understandable language the fundamental operating principle of the vacuum tube4 ,shows over #ajj different circuits for the practical use of the ,vacuum ,tube as a ,detector1 ,radio or ,audio ,frequency ,amplifier1 ,regenerative ,receiver1 ,beat ,receiver1 and ,generator of ,radio ,frequency ,currents4 ,more than #ajj diagrams reveal1 step by step1 in simple and direct form1 the uses of the vacuum tube4 99,cloth4 ,size #f x #i inches4 #bjb pages4 #aei diagrams and illustrations4 ,price1 #a4ge4 ,postage1 #aj cents499 ,practical ,wireless ,telegraphy ,by ,,elmer ,e4 ,,bucher ,more than #fe1jjj copies of this book have been sold to date4 ,it is used in practically every school1 college1 library and training camp in this country4 99,practical ,wireless ,telegraphy99 is the recognized standard wireless text book4 ,it furnishes much information of utmost value in regard to the very latest styles of wireless sets now in use4 ,it is the first wireless text book to treat each topic separately and completely1 furnishing a progressive study from first principles to expert practice4 ,starting with elementary data1 it progresses1 chapter by chapter1 over the entire field of wireless--fundamentals1 construction and practical operation4 99,size #f x #i inches4 #ceb pages4 #cdj illustrations4 ,handsomely bound in full cloth4 ,price1 #a4ge4 ,postage1 #aj cents499 ,radio ,telephony ,by ,,alfred ,n4 ,,goldsmith1 ,ph ,d4 99,it is the only book treating the subject of ,radio ,telephony in all its aspects499 ,this complete text on radio telephony is intended for radio engineers1 operators and experimenters1 also radio electricians in the ,navy1 men in the ,signal ,corps and especially men in the ,aviation ,service who handle radio equipment4 ,students and others who desire to be clearly informed concerning this newest and most interesting branch of electric communication need this book4 ,it is written in clear style1 and pre-supposes very little knowledge of radio4 ,fully illustrated with wiring diagrams and previously unpublished photographs of wireless telephone apparatus4 ,there are over #djj separate topics listed in a carefully prepared index4 99,size #f x #i inches4 #bef pages4 #bbf illustrations4 ,full cloth1 stamped in gold4 ,price1 #b4jj4 ,postage1 #aj cents499 ,the ,operation of ,wireless ,telegraph ,apparatus ,do your ,wireless friends come to you for advice on constructing and operating their apparatus or do you go to them for information8 ,here is a chance for ,,you to become the authority4 99,this book is a necessity to every ,progressive ,experimenter499 99,it shows how to obtain the very highest efficiency from any station1 and how to comply with the law4 ,how to tune1 adjust your detector1 spark gap1 phones1 etc499 99,price1 #cj ,cents1 ,postpaid499 ,this book was written for the wireless experimenter who has passed the amateur stage1 but explains how the beginner also can obtain the very best results from his station4 ,it contains much useful information to this end and many kinks4 99,,it ,,shows ,,how99 to receive or send on long or short wave lengths with highest efficiency1 to tune for longest distance reception of messages1 to use the buzzer test1 how to test and connect condensers1 receivers1 etc41 how to use receiving transformers1 variometers1 etc41 all with highest efficiency in view4 99,,it ,,also ,,describes99 the construction and use of a simple1 inexpensive wave meter to tune the station to any desired wave length1 and tells how to obtain a sharp wave and a pure wave4 99,model ,flying ,machines99 99,,how ,,to ,,build ,,and ,,fly ,,them99 ,will prove interesting and valuable4 ,have you ever built and flown a ,model ,racer8 ,if not1 you have missed something4 ,price1 #be ,cents1 ,postpaid4 ,model ,aeroplaning is one of the most fascinating and instructive of sports4 ,thousands of young men and boys have formed ,model ,aero ,clubs and organized ,flying ,contests throughout the country4 ,,model ,,flying ,,machines of the ,arts and ,sciences series is the only book giving reliable data and instructions for the construction of practical ,model ,aeroplanes4 ,,if ,,you ,,are ,a ,,beginner1 this is the book that you ought to have4 ,it will start you right4 ,it tells how to build seven different types of machines1 starting with the simplest ,monoplane and finishing with several ,long ,distance ,racing ,models4 ,,if ,,you ,,are ,,interested ,,in ,,model ,,aeroplaning1 this book will prove the one you have been looking for4 ,gives valuable ,kinks4 ,tells how to carve propellers1 make winders1 adjust and fly machines1 etc4 ,fully illustrated with large size1 detailed working drawings1 showing the exact size of each part4 ,twelve full-page plates4 ,printed on first-class paper4 ,heavy cover in three colors4 ,sent postpaid by return mail upon receipt of #be cents4 99,,every ,,model ,,aviator ,,ought ,,to ,,have ,a ,,copy99