,transcriber's ,note3 ,italic text is indicated by underscores1 boldface by equals signs4 ,small-caps text appears here as all-caps4 ,,how ,,to ,,install ,electric ,bells1 ,annunciators1 and ,alarms4 ,,including ,batteries1 ,wires and ,wiring1 ,circuits1 ,pushes1 ,bells1 ,burglar ,alarms1 ,high and ,low ,water ,alarms1 ,fire ,alarms1 ,thermostats1 ,annunciators1 and the ,location and ,remedying of ,troubles4 ,,by ,,norman ,h4 ,,schneider1 ,author of 8,the ,study of ,electricity for ,beginners10 8,care and ,handling of ,electric ,plants10 etc41 etc4 ,,second ,,edition1 ,,enlarged ,,new ,,york ,,spon ,,chamberlain1 #abc ,,liberty ,,street ,,london ,e4 ,f4 ,n4 ,,spon1 ,limited1 #eg ,,haymarket1 ,s4,w4 #aiac ,no4 #d ,copyright #aijd ,copyright #aiac ,by ,,spon ,,chamberlain ,the ,camelot ,press1 #af-ah ,oak ,st41 ,new ,york ,,preface ,among all the applications of electricity to domestic or commercial uses1 few are as widespread as the electric bell4 ,practically every building used for a dwelling1 storage or manufacture requires an electric bell1 annunciator or alarm system4 ,this book was written to explain in practical language how an electric bell system operates and how it is installed2 its success shown by its large sale has resulted in this new edition which brings the subject up to date4 ,many new diagrams of annunciator and burglar alarm systems have been added1 together with descriptions and illustrations of wiring elevators for electric bells1 wiring for door openers1 the use of transformers for furnishing suitable ringing current from electric light circuits2 and high voltage bells intended to be used on other than the customary low voltage battery circuits4 ,the author expresses his acknowledgment to the ,western ,electric ,company for diagrams of door opener circuits in connection with their interphone systems1 to ,edwards and ,company of ,new ,york for diagrams of fire alarms1 burglar alarms and annunciators1 and to the ,westinghouse ,company for illustrations of bell-ringing transformers4 ,,contents ,,introduction ,,page ,introduction4 ,the principle of an electric bell4 ix ,,chapter ,i ,the ,leclanche cell--,polarization--,setting tip--,the dry cell--,the gravity cell--,connecting up cells #a ,,chapter ,,ii ,the single stroke bell--,the shunt bell--,the differential bell--,the continuous ring bell--,the waterproof bell--,forms of gongs--,the buzzer--,long distance bells--,the relay--,the push--,three point or double contact push--,floor push--,door pull--,indicating push #i ,,chapter ,,iii ,bell wires--,joints--,running wires--,how to put up a door bell--,combinations of bells1 pushes and batteries--,faults in bells1 faults in wiring--,how to locate and remedy faults #bc ,,chapter ,,iv ,fire alarms--,thermostats--,metallic thermostats--,mercury thermostat--,how to connect thermostats--,water level indicators--,burglar alarms--,open and closed circuit alarms--,window1 door and shade springs--,alarm matting--,yale lock alarm--,door trip alarm #dj ,,chapter ,v ,the annunciator drop--,the needle or arrow drop--,the pendulum drop--,wiring up annunciators--,return or fire call systems--,double wire system--,western ,electric single wire system #ee ,,chapter ,,vi ,three-wire return call system--,installing elevator annunciators--,burglar alarm annunciators--,clock alarm circuit--,bells for high voltages--,bell-ringing transformers--,combination bell1 door opener and telephone circuits--,fire alarm circuit--,interior fire alarm system--,fire alarm system for considerable areas #fd ,,list ,,of ,,illustrations ,,fig4 ,,page #a ,electric bell1 push1 and battery x #b ,leclanche cell #a #c ,dry cell #d #d ,gravity cell #e #e ,vibrating bell #aj #f ,single stroke bell #aj #g ,shunt or short circuit bell #aj #h ,continuous ring bell #ac #i ,waterproof bell #ad #aj ,dome gong #ae #aa ,tea gong #ae #ab ,cow gong #ae #ac ,sleigh bell gong #ae #ad ,spiral gong #ae #ae ,relay and circuit #af #af ,door push #ai #ag ,pear push #ai #ah ,door push #ai #ai ,wall push #ai #bj ,floor push #bj #ba ,door pull attachment #bb #bb ,wire joint first operation #be #bc ,wire joint second operation #be #bd ,wire joint insulating #be #be ,section of house showing wiring #bi #bf ,bell with ground return #cj #bg ,pushes in multiple #ca #bh ,bells in series #ca #bi ,bells in multiple #ca #cj ,two bells and two pushes #cb #ca ,two bells and two pushes #cb #cb ,two bells1 two pushes and one battery #cc #cc ,double contact push #cc #cd ,grounded bell #cd #ce ,tongue test of wiring #ch #cf ,knife test of wiring #ch #cg ,knife test of wiring #ci #ch ,metallic thermostat #dj #ci ,mercury thermostat #da #dj ,mercury thermostat circuit #db #da ,water level alarm #dd #db ,lever water level alarm #de #dc ,high or low water level alarm #de #dd ,window spring for burglar alarm #dg #de ,burglar alarm--closed circuit #dg #df ,special bell connection for burglar alarm #dh #dg ,special bell connection for burglar alarm #di #dh ,burglar alarm and relay #ej #di ,window-shade contact spring #ea #ej ,house wired for burglar alarm #eb #ea ,door trip alarm #ec #eb ,annunciator drop #ee #ec ,needle drop #ef #ed ,needle drop indicating #ef #ee ,pendulum drop #eg #ef ,annunciator drop circuit #eh #eg ,simple annunciator circuit #ei #eh ,annunciator and fire call circuit #fj #ei ,single-wire room and fire call #fa #fj ,three-wire return call circuit #fe #fa ,elevator bells and annunciator circuit #fg #fb ,burglar alarm annunciator circuit #fi #fc ,clock alarm circuit #ga #fd ,bell-ringing transformer #gc #fe ,bell-ringing transformer with three secondary voltages #gc #ff ,western ,electric interphone system #ge #fg ,western ,electric interphone system for more extensive service #gg #fh ,fire alarm circuit #gi #fi ,interior fire alarm circuit #ha #gj ,fire alarm circuit for considerable areas #hb ,,introduction ,an electric bell depends for its action on the fact that a piece of iron wound with insulated wire becomes a magnet and will attract another piece of iron just so long as an electric current is allowed to travel through the wire4 ,the instant the current ceases1 the magnetism also ceases1 and the attracted piece of iron 7termed the armature7 is no longer held in contact4 ,the general construction of an electric bell is shown in ,fig4 #a4 ,m ,m are coils of insulated wire wound on soft iron cores4 ,a is a soft iron armature mounted on a flat spring so that it is normally kept a slight distance away from the soft iron cores4 ,s is a brass screw with a platinum tip touching a platinum disc on a spring attached to the armature4 ,when the push button ,p is pressed down1 its two brass springs touch each other1 the current from the battery cell ,b then flows through the wire ,w1 through the push ,p1 through the coils ,m ,m1 along ,a to the platinum disc1 out at ,s1 which touches this disc1 and back to the battery4 ,illustration3 ,,fig4 #a ,the instant this is done the current causes the iron cores to become magnets1 they attract ,a1 which then breaks contact at ,s4 ,the spring mounting of ,a causes it to jump back to its first position1 ,s then touches the platinum disc again1 the current flows as before1 and the armature is again attracted only to break contact with ,s and fly back4 ,this continual making and breaking of the circuit keeps up as long as the push is pressed1 a ball mounted on ,a by means of a rod strikes against the gong ,g causing a continuous ringing of the bell4 ,the wires leading between the bell1 battery cell and push must all be insulated1 that is1 covered with cotton1 rubber1 etc41 which prevents the leakage of current should two wires cross each other4 ,copper wire is mostly used for circuits indoors1 the details of the kind and size of wire will be given later on4 ,the main parts of an electric bell circuit are then--the battery to supply the electric current2 the circuit1 or wires1 to carry this current2 a push1 or circuit breaker1 to control the current flow2 and a bell to utilize the current4 ,,chapter ,i ,the ,battery ,the ,battery ,cell4 ,the battery cell most used in electric bell work is the ,leclanche1 or some modification of it4 ,illustration3 ,,fig4 #b ,the ,leclanche battery cell is shown in ,fig4 #b1 where ,j is a glass jar1 ,z a rod of zinc1 and ,p a jar of porous earthenware containing a carbon rod surrounded by powdered carbon and peroxide of manganese4 ,in setting up this cell about four ounces of sal ammoniac 7chloride of ammonia7 are put into the jar and enough water added to come about half way up the jar4 ,the porous jar ,p and the zinc ,z are then inserted1 and the cell is ready for use in a few minutes after the liquid has soaked through the earthenware into the carbon-manganese mixture4 ,water is often poured into the porous jar through holes in its top to hasten this wetting4 ,wires are clamped by nuts or set-screws to the negative terminal on the zinc or the positive terminal on the carbon1 it generally not being of consequence which terminal is attached to either wire of the circuit4 ,a battery cell could be constructed without the manganese1 using simply a plate of carbon and a rod of zinc1 but hydrogen gas would be generated on the carbon plate when the cell was working and would stop the current flowing4 ,this is called polarization1 and peroxide of manganese is a de-polarizer1 because it combines with this hydrogen gas almost as fast as it is generated1 and prevents1 to a great extent1 the polarization4 ,but it does not stop it entirely1 as will be seen if the ,leclanche cell is kept working above its capacity4 ,then the hydrogen is generated too fast for the manganese to destroy it1 and the cell ceases to work4 ,in this case a rest will often restore the cell to its former power4 ,cells which have been almost unable to make a bell give even a single tap have been found good again when allowed to remain at rest over night4 ,in setting up a battery cell no liquid should be splashed on the brass terminals or corrosion will take place4 ,every metal surface where connection is made to allow electric current to pass must be clean and bright1 and all screws1 or nuts1 holding wires must be screwed up tight so that the wires are firmly clamped4 ,loose or dirty connections are the cause of probably eight out of every ten troubles affecting bells and batteries4 ,when the fluid in a ,leclanche cell becomes milky1 more sal ammoniac must be added4 ,or1 better still1 throw out the old solution1 wash the porous jar thoroughly in clean water1 scrape the zinc bright1 and half fill the cell with fresh solution4 ,the zinc wearing away rapidly or becoming covered with crystals1 and a strong smell of ammonia1 show generally that the cell is being worked too hard1 or that the current is leaking where it should not4 ,a zinc rod in a cell working the average door bell should last for six months1 the porous jar for a year4 ,the ,dry ,cell4 ,the ,leclanche cell being a cell with much free liquid is liable to dry up if not watched4 ,the dry cell 7,fig4 #c7 is a modern form of the ,leclanche where the liquid is held by an absorbent material1 such as blotting paper1 or plaster4 ,illustration3 ,,fig4 #c ,a typical dry cell,a is shown in the figure4 ,an outside case of zinc is lined with blotting paper dampened with chloride of zinc and sal ammoniac4 ,a carbon rod is then inserted in the centre and packed around with carbon dust and peroxide of manganese4 ,the latter mixture is also somewhat dampened4 ,a ,for full description of this class of battery see ,no4 #c ,book on 8,dry ,batteries40 ,molten wax1 or a suitable composition1 is then poured on top of the contents of the cell to seal it up and prevent the evaporation of the fluid4 ,a terminal on the carbon rod and another on the zinc case complete the cell4 ,illustration3 ,,fig4 #d ,the voltage of both the ,leclanche and the dry cell is about #a4de1 when it goes below this it indicates that the cell is worked out4 ,the two cells described are known as open-circuit cells and are only intended for intermittent working4 ,when a current is needed for a long period at a time a closed circuit cell should be used1 such as the gravity ,daniell cell4 ,the ,gravity ,daniell ,cell4 ,the gravity cell1 ,fig4 #d1 has a zinc block ,z suspended from the side of the jar and a number of copper leaves ,c standing on edge at the bottom4 ,a quantity of bluestone 7sulphate of copper7 is poured over the copper leaves and the jar filled with water4 ,during the working of this cell1 copper is deposited on the copper plate1 and sulphate of zinc formed at the zinc4 ,to hasten the action a small quantity of zinc sulphate can be added to the solution when setting up the cell4 ,the name of this cell comes from the fact that the copper solution being heavier remains at the bottom of the jar4 ,if the cell is not worked enough1 all the solution will become blue and the zinc will blacken4 ,if very dirty from this cause1 remove the zinc1 scrape and wash it thoroughly4 ,throw out all the solution1 add new sulphate and water and replacing the zinc1 then put the cell on short circuit by connecting the copper and zinc together for a few hours4 ,e4 ,m4 ,f4 ,the e4 m4 f4 of a gravity cell is within a fraction of one volt1 its current nearly one-half ampere4 ,warmth makes it give a greater current2 on no account let a gravity cell freeze4 ,resistance of a ,cell4 ,the fluids in a cell do not conduct electricity as well as copper does2 they offer more resistance and thus reduce the current output4 ,the internal resistance of a cell may be lowered by using large zinc plates curled around the porous pot4 ,the ,samson cell has a large zinc plate bent in the form of a cylinder1 the carbon-manganese combination standing in the centre of it4 ,the dry cell also has a large zinc1 the internal resistance being thus much lowered1 the current output is increased4 ,this is by reason of ,ohm's law1 which teaches that to increase the current flow1 either the voltage of the battery must be increased1 or the resistance decreased4 ,but increased current means lessened life2 there is only just so much energy in a cell mainly dependent on the quantity of chemicals4 ,grouping of ,cells4 ,cells may be grouped in a battery to get increased voltage1 or increased amperage4 ,when connected for the former1 they are in series1 the carbon of one is connected to the zinc of the next1 and so on4 ,if all the carbons are connected together and all the zincs1 they are in multiple1 and will give the same voltage as of one cell but the combined amperage of all4 ,in ordinary bell work the series is the general connection1 the higher the resistance of the circuit1 or the longer the wires1 the more voltage is required4 ,,chapter ,,ii ,bells and ,pushes ,electric ,bells4 ,the two main types of house bells are the iron box and the skeleton4 ,the iron box has a cast-iron frame1 or base1 and a cast- or stamped-iron cover over the mechanism4 ,the skeleton bell has an iron frame but no cover1 and is generally better finished and more expensive than the iron box bells4 ,for fire alarm purposes1 mechanical bells or gongs are made1 in which a clockwork mechanism causes the hammer to strike the gong upon being released by electromagnetism4 ,marine or waterproof bells have an iron cover fitting tight over a rubber gasket2 they are for marine1 or mining1 work4 ,polarized1 or magneto1 bells are used in telephone work1 and are rarely operated by a battery1 but have a miniature dynamo generator operated by hand1 or power1 to supply the actuating current4 ,most bells are classed for size by the diameter of the gong1 a four-inch bell being one with a gong four inches in diameter2 a six-inch bell one with a six-inch gong1 and so on4 ,according to the use for which they are intended1 bells may be vibrating1 as before described1 single-stroke1 shunt or short-circuiting1 differential1 continuous-ringing1 or adapted for circuits of high voltage4 ,the ,single-stroke ,bell4 ,the bell before described1 and again shown in ,fig4 #e1 is a vibrating1 or trembling1 bell4 ,it is often desired to have the hammer give only one stroke for each pressure of the push1 as in signaling with a code of taps2 in this case a single-stroke bell is used4 ,the circuit from the binding posts is then directly through the magnet coils without any break at the contact screw1 as in ,fig4 #f4 ,illustration3 ,,fig4 #e ,,fig4 #f ,,fig4 #g ,in adjusting such a bell to give a clear sound1 press the armature up against the iron magnet cores and then bend back the hammer until it just clears the gong4 ,the spring of the hammer wire will carry the hammer sufficiently forward to hit the gong4 ,the tone will be clearer than if the hammer dampered the gong by pressing against it when the armature was nearest the core4 ,by bringing out a third connection1 a vibrating bell may be made both single stroke and vibrating4 ,the ,shunt ,bell4 ,there is a form of bell1 ,fig4 #g1 known as the shunt1 or short circuit bell1 which is often used when two or more are to be connected in series1 as will be seen in the description of circuits4 ,in this bell the circuit through the magnets is not broken at the contact screw1 but the forward movement of the armature short circuits the coils4 ,as the short1 or shunt1 circuit is very much lower in resistance than the wire on the magnet coils1 the main current flows around the latter and they do not become energized4 ,the sparking at the shunting contact screw is much less than it would be at the ordinary breaking contact screw1 and the platinum points last longer4 ,the ,differential ,bell4 ,sparking at the breaking contacts of an electric bell is detrimental to the platinum points1 and many remedies have been devised to overcome it4 ,sparking is due to the self-induction of one turn of the wire coil acting on its neighbor1 and this property is utilized in the gas engine1 or gas-lighting spark coil1 where a fat spark is needed to ignite gas4 ,the differential bell has two windings in opposite directions4 ,the action of one would be to produce an ,n-pole at one end and an ,s-pole at the other4 ,but the second coil produces poles just the opposite1 as the polarity of a magnet depends on the direction in which the current flows around it4 ,where the current flows around the first winding the armature is attracted and its spring contact meets the contact screw and allows the current to divide1 part flowing through the first coil1 the other flowing in the reverse direction in the opposite way4 ,one coil would tend to produce an ,n-pole where the other coil produced an ,s-pole1 and these opposite poles would so neutralize each other that there would be no magnetism4 ,the armature would therefore be pulled back by its spring when both coils were thrown into circuit4 ,in so doing it would cut out one coil and the same series of operations would recommence4 ,as a spark is normally produced where magnetism is lost by a break of circuit1,b no spark appears1 as magnetism is produced by a break of circuit in this case4 ,b ,for a full explanation of self-induction see ,no4 #a of this series4 ,continuous-ring ,bell4 ,in some classes of bell work1 such as burglar alarms1 it is desired that the bell when once started shall continue to ring until stopped by the person called4 ,in this case a continuous-ringing bell is needed1 such as in ,fig4 #h4 ,illustration3 ,,fig4 #h ,when the push ,p is pressed1 the current flows in the usual way through contact screw ,l1 armature spring ,a1 magnet coils ,m ,m1 battery ,b1 back to ,p1 and the bell rings4 ,but on the first forward movement of the armature it releases the spring contact ,s1 which flies forward and makes contact at ,u4 ,the circuit is now from ,b1 through ,m ,m1 to ,a1 thence through ,l and ,s1 to ,u and back to ,b4 ,the bell will continue to ring until the spring contact ,s is moved back and caught by the projection on the armature ,a4 ,a continuous-ring attachment is also made and sold in most electrical supply stores1 which is complete in itself and can be applied to any bell4 ,illustration3 ,,fig4 #i ,waterproof ,bells4 ,in ,fig4 #i is an example of a waterproof bell where the mechanism is almost all entirely encased in a waterproof brass case4 ,the circuit is made and broken inside the case1 but the magnet cores project through it and act on a second armature placed outside4 ,this second armature carries the hammer which strikes the gong and is governed in speed by the contact-breaking armature inside4 ,forms of ,bell ,gongs4 ,in order to provide a variety of sounds1 bells are provided with gongs of various shapes4 ,fig4 #aj shows the ordinary form of gong4 ,fig4 #aa1 a tea gong2 ,fig4 #ab1 a cow gong2 and ,fig4 #ac1 a sleigh bell4 ,illustration3 ,,fig4 #aj ,,fig4 #aa ,,fig4 #ab ,,fig4 #ac ,a coil of steel wire is also used1 as in ,fig4 #ad1 which on being struck by the hammer gives a pleasant but not loud tone4 ,illustration3 ,,fig4 #ad ,the ,buzzer4 ,the buzzer is the mechanism of a vibrating bell less the hammer and gong4 ,as the armature vibrates it makes a buzzing noise which does not carry as far as the sound from a struck gong4 ,it is used chiefly for a desk call and in telephone exchange work1 or any place where general attention is not desired to the signal4 ,operating ,bells at a ,distance4 ,when it is desired to ring a bell situated at a considerable distance from the push1 the resistance of the line becomes objectionable4 ,illustration3 ,,fig4 #ae ,on lines of #ejj feet1 ,no4 #ah copper wire and upwards1 the battery necessary would be very large1 two small batteries and a relay would prove more satisfactory4 ,in ,fig4 #ae the circuit of a simple form of relay is given4 ,an adjustable contact screw ,c is placed where an extension ,s of the armature ,a can strike it4 ,this extension is provided with a platinum contact4 ,the connections are as in the figure4 ,when the push ,p is depressed1 the current from the main battery ,m energizes the electromagnet ,e1 and the armature ,a being attracted1 contacts ,s and ,c meet4 ,these contacts close the second circuit containing the bell ,b and the local battery ,l4 ,the relay resembles a second push near the bell1 but controlled by current from a distance instead of being depressed by hand4 ,its advantage consists in it needing but a very weak current to move the armature ,a1 which is held back by a light spring1 or by gravity4 ,the relay may then be set near the bell and the wires from the push may be of a very great length4 ,battery ,l1 which actually rings the bell1 will thus only have to work through a few feet of wire4 ,reducing ,resistance of a ,bell4 ,sometimes it is desired to reduce the resistance the bell coils offer to the current1 the bell then working over a very short line with few cells of battery4 ,or the bell coils may have been wound with fine wire for large battery voltage and a long line4 ,the bell coils may be put in multiple1 the current then dividing and one-half going through each spool4 ,untwist the joint between the spools near the yoke or iron bar to which the spools are attached4 ,join one of these ends to the wire at the armature end of the other spool and the second untwisted end to the armature end wire of its neighboring spool4 ,use short pieces of insulated wire for these extra connections4 ,the current now instead of having to go through one spool and then the other1 can branch through both at once4 ,the resistance to the current of one spool is half the resistance of two1 the current through one spool will therefore be twice that through the two spools as at first connected4 ,and as there are two paths for it1 each one-half the first resistance1 the total will be only one-fourth the resistance of the ordinary series arrangement4 ,the same size battery will therefore send four times the current through the spools in multiple than when they are in series4 ,it is to be noted that the wire on one spool is wound in the reverse direction to that on the other4 ,the reason will be apparent if the two spools and yoke are considered as merely one spool bent in a ,u or horseshoe form4 ,if both spools were wound in the same direction they would be in opposite directions when the ,u were straightened out1 and would cause like poles at the same ends4 ,these poles would neutralize one another1 so that there would be no magnetic attraction4 ,this can be readily proved by joining together the two yoke ends and the two armature ends of the spool wires4 ,then pass the current through these two joined connections4 ,illustration3 ,,fig4 #af ,,fig4 #ag ,,fig4 #ah ,,fig4 #ai ,the ,push ,button4 ,push buttons1 or pushes1 are made in a variety of forms1 with metal1 wood1 hard rubber1 or porcelain bases4 ,fig4 #af has a metal base1 and is suitable for a front door4 ,fig4 #ag is a wooden pear push1 and is attached at the end of a cord which has the two conductors braided in it1 each1 however1 having its own insulation4 ,fig4 #ah is a plate push for an outside door4 ,fig4 #ai is either of metal1 wood1 or porcelain1 and is the shape most commonly used4 ,a three-point push has three contact springs4 ,one is movable by means of the button1 one is below the movable spring1 and the third is above it4 ,illustration3 ,,fig4 #bj ,when the push button is not being depressed1 the movable spring makes contact with the upper spring4 ,but when the button is depressed1 these two springs part1 and the movable spring makes contact with the lower one4 ,this style of push is used for special bell and annunciator work1 as will be described later4 ,the form of combination floor and table push in ,fig4 #bj is the most solidly constructed device of its kind4 ,the lower part is set in a hole bored in the flooring1 the metal flange keeping it in place and preventing its slipping through4 ,the floor push attachment works as follows3 ,the central metal rod is divided into two parts ,b ,d1 by an insulating piece of hard rubber4 ,when depressed against the action of the spiral spring by the foot1 the upper part ,b connects together the contact springs ,a ,c1 closing the circuit of bell and battery4 ,these contact springs are insulated from each other by a hard rubber block ,r4 ,from the table push a cord containing two insulated wires leads to the two parts of the rod at ,b and ,d4 ,when the push centre is pressed down1 the push springs come together and practically short circuit ,b and ,d1 which completes the circuit of bell and battery4 ,at any time the centre rod may be removed1 leaving a surface almost flush with the carpet1 or floor1 over which furniture may be moved without injury to the mechanism of the push4 ,for a floor push alone a shorter form of the centre rod is also sometimes furnished which is not divided by insulation4 ,the spiral spring keeps it clear of the lower contact ,a but enables it to always make connection with the upper contact ,b4 ,pressing this rod down will also short circuit the bell and battery so that the signal is given4 ,a door pull attachment1 like ,fig4 #ba1 is made so that the ordinary form of lever pull bell may be changed into an electric bell4 ,being screwed up near the door pull1 a wire is run from the latter and fastened to lever ,l4 ,when the pull is drawn out the lever ,l turns on a pivot and a projection presses the insulated spring ,s against the metal base ,b4 ,the circuit of the bell and battery being thus closed1 the bell rings4 ,illustration3 ,,fig4 #ba ,indicating ,push ,button4 ,a push button is made which contains in the base a small electromagnet in series with the line4 ,an armature on a spring is fixed near the magnet poles4 ,when the push is depressed1 the current travels through this electromagnet1 and as the circuit is made and broken at the distant bell1 it is also interrupted in the electromagnet4 ,the armature vibrates in unison with the bell and thus gives an audible indication that the bell is ringing4 ,,chapter ,,iii ,wiring1 ,circuits and ,troubles ,the ,wire4 ,the size of the copper wire used in bell work is ,no4 #af1 or ,no4 #ah1 ,b and ,s gauge1 and sometimes smaller1 such as ,no4 #bj to #bb4 ,but smaller wire than ,no4 #ah has too much resistance1 and would necessitate a larger battery power1 even if its mechanical strength were not too low4 ,the insulating coverings are cotton saturated with paraffin wax or compounds4 ,the covered wires are variously known as annunciator1 office1 or weatherproof wire1 these terms being mostly for distinction of the coverings and not for the use to which the wire would be put4 ,annunciator wire has two layers of cotton merely wrapped around the copper and then saturated with paraffin4 ,office wire has the two cotton layers braided1 the inside one being filled with a moisture-repelling compound4 ,both office and annunciator wires have their outside coverings filled with paraffin and highly polished4 ,from the ease with which annunciator wire is stripped of its cotton covering1 the braided office wire is to be preferred4 ,these coverings are made in a variety of colors4 ,weatherproof covered wire is mostly used for electric light work1 but the sizes given above are good for bell work1 although their larger outside diameter makes them harder to conceal4 ,the approximate number of feet to the pound of office and annunciator wire is given in the table4 ,office ,wire4 ,annunciator ,wire4 ------------------------------------ ,no4 ,feet per lb4 ,no4 ,feet per lb4 ------------------------------------ #ab #ce #ah #ahj #ad #ee #bj #bbe #af #ie #ah #ace ,joints4 ,upon the care with which a joint is made much depends1 a loose or poorly made joint will offer much resistance to the current4 ,the correct way to start a joint in annunciator1 or office1 wire is shown in ,fig4 #bb4 ,about three inches of each wire to be joined is bared of its insulation and scraped bright4 ,the ends are then bent at right angles to each other1 hooked together and one end firmly twisted around the other1 as shown in ,fig4 #bc4 ,any projecting pieces are cut off1 and the joints should then be soldered to prevent corrosion4 ,illustration3 ,,fig4 #bb ,,fig4 #bc ,,fig4 #bd ,adhesive tape 78friction tape07 is wrapped around the joint1 ,fig4 #bd1 and pressed firmly together so that there is no chance of its unravelling4 ,the tape wrapping should extend across the joint and on to about a half inch of the insulation around each wire4 ,running the ,wires4 ,to detail all the operations of installing a complex system of bell1 alarm and annunciator wires would be impossible from the reasons that conditions vary and space is limited4 ,general directions will then only be given to enable the inexperienced to run such wires as may be needed in ordinary domestic work and to guard against the most common causes of failure4 ,wires may be run in tin tubes to prevent the depredations of rats and mice1 or they may be run with simply their own covering for protection2 it is presumed the latter is undertaken4 ,in a case where the building is of frame and in course of erection the task is much simplified4 ,having first decided upon the plan1 number of bells1 pushes1 etc4 and their location1 proceed to run the wires first in order that the pushes1 bells1 etc4 may not be injured4 ,but where the house is already occupied1 as in the majority of cases likely to be met with by the reader1 the bell and battery may be set first4 ,take the case of an ordinary door bell with the push at the front door1 the bell in the kitchen and the battery in the cellar4 ,if possible get the wire on two spools2 it will simplify matters if both wires are of different colors4 ,starting at the push1 have a foot of each wire for connection and slack1 and fasten each wire lightly to the woodwork with staples1 or double-pointed tacks1 never putting two wires under one staple nor driving in a staple so it cuts the insulation4 ,some cases will require a staple about every foot1 on straight runs sometimes every three feet4 ,in many cases the wires can be partly concealed in the angle between a moulding and the wall1 or even in a groove of the moulding itself4 ,when running along a skirting1 the wires may often be pushed out of sight between it and the floor4 ,do not attempt to draw the wires too tight or the changes of the weather may break the wires when the woodwork shrinks or swells4 ,the wires will be1 one from the push to the bell1 one from the push to the battery1 and one from the bell to the battery4 ,so it is probable that the second wire can be run right through a small hole bored in the flooring under the push1 but inside the front door4 ,in this case it will be perhaps easier if the spool be left in the cellar and the end of the wire be pushed up from below and stapled to the woodwork near the push1 leaving the cellar work to the last4 ,only one wire will be run then direct to the bell upstairs and it can be better concealed than two4 ,if necessary it may be drawn under a carpet and not stapled1 or it can often be forced into the crack between two boards4 ,but if not1 run it along the skirting1 following the walls until it reaches below the bell4 ,it is often better to go entirely around a room than to cross below a door4 ,if a door must be crossed the wire may either run up one side of the frame and down the other or laid beneath the carpet on the sill4 ,the former is preferable1 but takes more wire4 ,in many houses the bell wire as well as the battery wire may be run across the cellar beams 7,fig4 #be71 in which case bore a second hole for it near the push2 do not draw it through the same hole as the push to battery wire4 ,and1 of course1 here work upwards with the spool in the cellar4 ,having reached the bell location1 run the third wire down into the cellar to the battery4 ,now connect up the push1 baring an inch or so of each wire1 push them through the holes provided in the push base1 screw down the push base and clamp the wires under the washers through which the connection screws run4 ,do this neatly1 be sure the ends of the wires do not stick out1 cut off what is left free of the bared ends4 ,then connect the battery to the wire from the push and the wire from the bell4 ,the last thing is to scrape and fasten the bell wires to the bell binding posts4 ,do this so that they cannot come loose and that they make good contact4 ,illustration3 ,,fig4 #be ,the bell should now ring properly when the push is pressed4 ,to sum up1 one wire leads from one spring of the push to the bell1 one wire from the other spring of the push to the battery1 and another wire from the remaining binding post on the bell to the remaining binding post on the battery4 ,it is immaterial whether the zinc terminal or the carbon terminal go to the bell or push4 ,combinations of ,bells and ,pushes4 ,one of the wires in a bell circuit may be replaced by the ground 7,fig4 #bf74 ,connection may be made to a gas or water pipe or to a metal plate buried deep in damp earth4 ,any wire fastened to such a plate must be thoroughly soldered to it or a voltaic action will be set up1 which will eat it away at the point of contact4 ,illustration3 ,,fig4 #bf ,when one bell is to be rung from two or more points the pushes are to be connected in multiple 7,fig4 #bg7 as if they were in series2 all would have to be closed to complete the circuit4 ,illustration3 ,,fig4 #bg ,illustration3 ,,fig4 #bh ,if two bells are to be operated from one push they may be in series 7,fig4 #bh71 but in this case one of them must be arranged for single stroke4 ,if both were vibrating bells the armature of one would not vibrate in unison with the other armature and the result would be irregular contact breaking and intermittent ringing4 ,illustration3 ,,fig4 #bi ,a preferable connection for two or more bells and one push is ,fig4 #bi1 where the bells are in multiple4 ,this requires more current than the series method4 ,illustration3 ,,fig4 #cj ,illustration3 ,,fig4 #ca ,to ring two bells from either one of two points1 the arrangement in ,fig4 #cj will answer4 ,it requires only two wires or one wire and ground return1 but two batteries4 ,as both bells are in multiple both will ring1 the one nearest the push being depressed ringing the loudest4 ,this is a disadvantage4 ,if the series arrangement in ,fig4 #ca be selected1 one bell must be arranged for single stroke4 ,both bells will ring with equal power4 ,illustration3 ,,fig4 #cb ,in ,fig4 #cb only the distant bell rings1 the circuit having only one battery but three wires1 or two wires and ground return4 ,a plan where two batteries are needed but only two wires1 or one wire and ground is in ,fig4 #cc4 ,double contact or three-point pushes are necessary here1 making one contact when depressed and a second one when not being touched4 ,illustration3 ,,fig4 #cc ,in this figure only the distant bell rings4 ,faults in ,bells4 ,on examining many electric bells it will be noted that only one binding post is insulated from the frame when the latter is of iron 7,fig4 #cd74 ,as the armature spring ,s is in electrical connection with the frame ,f by reason of its metal screws and support1 the circuit may run from the insulated post ,u to the magnet coils1 thence through the insulated contact screw ,c through the armature spring 7when it is making contact7 and through the frame to the uninsulated post ,i4 ,illustration3 ,,fig4 #cd ,this saves labor1 wire and complication1 but if the insulation of the post ,u1 the wires ,w ,v1 or the contact screw ,c be injured1 the current may take a short path back to the frame4 ,if ,c were thus grounded1 the bell would act as a single-stroke bell4 ,if ,u were grounded1 the bell would not ring at all1 as that would be a short circuit on the battery between ,i and ,u and the latter would also result if the bare wire were touching the frame at ,v4 ,if the bare wire touched the frame beyond ,m ,m1 that is1 along ,w1 it would be a single-stroke bell1 as if ,c were grounded4 ,as any one of these faults is likely to occur1 they should be looked for when the bell acts imperfectly1 or not at all4 ,a very common fault in a bell is when its armature sticks to the cores and thus does not make contact with the contact screw4 ,this may be from a weak spring or because of the loss of the pieces of brass inserted in the ends of the cores to keep the armature away from actual contact4 ,a piece of a postage stamp stuck over the core end will often help out in the latter case4 ,a high screeching noise from the armature vibrating too rapidly but with too little play1 may be from excessive battery power or the contact screw being too far forward4 ,the former will generally be detected by the violent sparking as well as the rapid vibration4 ,in very cheap bells the platinum contacts may be replaced by ,german silver or some other metal4 ,platinum is necessary because the sparking would soon corrode other metals1 but it is very expensive4 ,to test for platinum put a tiny drop of nitric acid on the suspected metal4 ,if bubbles or smoke appear it is not platinum4 ,after applying this test in any case however1 carefully wash off and remove all traces of the acid1 as it will corrode the metal into which the platinum is riveted4 ,dirty contacts will decrease the current in the bell coils and it will not work well1 if at all4 ,loose contact screws and wires also give trouble4 ,the adjusting of the contact screw is of the utmost importance1 and should never be attempted unless it is clearly necessary4 ,faults in ,line4 ,in looking for a fault in a bell circuit make sure the battery is working2 if only one or two cells1 put the ends of two wires attached to the terminals on the tongue3 a metallic taste will indicate current4 ,then see that the circuit wires are firmly clamped in the terminals and no dirt or corrosion on the connections4 ,next examine the push button and see that the wire connections at the springs are perfect4 ,if there is no movement of the bell at all when the push is pressed in1 take a pocket knife or screw driver1 and touch the blade across the push springs4 ,if there is current flowing sparks will be seen when the blade breaks contact between the springs4 ,if there are no sparks1 detach the wires from the bell and twist the bare ends together4 ,then try again for sparks--they may now be very minute4 ,the tongue test is good here4 ,if current is detected1 examine the bell for the defects first mentioned4 ,but if no current is found at the push now the wires are broken somewhere4 ,first short circuit the push springs by inserting a knife blade or piece of wire so as to touch both of them4 ,then touch the two wires at the bell1 one to each side wire coming from the magnet coils4 ,if current is up to the bell and the coils are all right1 a single stroke should result4 ,replace the wires in the binding posts1 clean the platinum on both contact screw and armature spring and try the adjustment4 ,troubles in the bell will be mostly similar to those before mentioned4 ,if no current has been obtained at either bell or push1 and the battery is in good working order1 the line must be tested for a cross or break4 ,if the wires are touching each other 7,fig4 #ce7 at some bare spot ,s between the bell and the battery1 it will be shown by the metallic taste upon detaching one wire from the battery and laying it on the tongue ,t1 together with another wire ,w from the disconnected terminal of the battery4 ,the current will travel from the battery to the cross at ,s1 then back along the second circuit wire to the tongue and through the short wire to the battery4 ,illustration3 ,,fig4 #ce ,if no current is obtained in this way it is probable that the wire is broken4 ,illustration3 ,,fig4 #cf ,the easiest way to find this is to take a bell to the battery and connect it between the circuit wires and the battery 7,fig4 #cf74 ,then with a sharp knife carefully cut away a little piece of the insulation from each wire beyond the bell and battery and short circuit the bared spots with the knife blade ,k4 ,keep working towards the push4 ,the bell will ring each time at ,k ,k until the break ,d is passed1 at ,c it will not4 ,it becomes an easy matter then to locate it4 ,illustration3 ,,fig4 #cg ,if the bell and push are far apart1 as in ,fig4 #cg1 a break between the push and the bell may be found as shown4 ,with the knife blade ,k at different points the bell will ring1 but after passing the break ,d it will not ring4 ,such simple tests as are here given can be carried out by any one1 but far better results will be obtained if the reason for each is first learned4 ,this can be readily done by a careful study of the diagrams and text4 ,,chapter ,,iv ,alarms ,fire ,alarms4 ,thermostats1 heat alarms and fire alarms are all practically the same1 the term thermostat being applied principally to the apparatus which closes the electrical circuit4 ,illustration3 ,,fig4 #ch ,thermostats act on the principle that heat causes expansion whether of substances1 liquids1 or gases4 ,the degree in which different substances expand varies for the same increase in temperature4 ,this fact is used in a common form of thermostat shown in ,fig4 #ch4 ,a strip of wood or hard rubber ,r has a strip of thin sheet metal ,s riveted to it4 ,this compound strip is held at one end by a lug ,l screwed fast to a baseboard4 ,upon an increase of temperature the hard rubber expands more than the metal strip and the compound strip bends towards the adjustable contact screw ,a4 ,upon touching the latter1 the circuit through the bell ,b1 battery ,c and the metal strip ,s is completed1 and the bell rings4 ,a contact screw can be arranged at the other side of ,s ,r1 which will give warning of a decrease in temperature1 as the rubber contracts more than the metal strip4 ,illustration3 ,,fig4 #ci ,in some thermostats of this character two metals having different coefficients of expansion1 such as steel and brass1 are used instead of metal and hard rubber4 ,thermostats of this nature are much used in incubators1 and they can readily be combined with electric apparatus to open or close hot-air valves1 dampers1 etc41 and thus regulate the supply of hot air1 hot water1 or gas4 ,a thermostat much used in fire alarm work has a thin metal chamber which is air tight4 ,an increase of temperature causes the air to expand1 which swells out the walls of the chamber and closes an electric circuit4 ,illustration3 ,,fig4 #dj ,the mercurial thermostat shown in ,fig4 #ci has a glass tube ,t and bulb containing mercury4 ,into each end is sealed a platinum wire ,p ,p4 ,upon the temperature rising to a predetermined degree1 the expanded mercury completes the circuit between ,p ,p and the battery ,c and bell ,b are put in operation4 ,fig4 #dj is the open circuit system most used by the fire alarm companies1 only one circuit of six thermostats being illustrated4 ,it will be seen that if any thermostat closes the circuit between the outer and inner wires of the ring ,a ,b1 current will flow through the corresponding drop of the annunciator and will attract the armature ,a of the relay4 ,this will cause the bell to ring4 ,as the relay is connected to the annunciator as before shown for the annunciator bell1 it offers a common path for any drop to the battery4 ,thus the bell will ring for any circuit1 but the individual drop only will fall4 ,in a simpler circuit the relay may be dispensed with and a vibrating bell only used4 ,thermostats may be operated on open or closed circuits1 that is1 they may give the alarm by closing a circuit and ringing a bell1 or by opening one and releasing a contact spring as in the burglar alarm system to be described later4 ,water ,level ,alarms4 ,where it is desired to signal the rising or falling of water in a tank above or below a given point1 a water level indicator as in ,fig4 #da may be used4 ,a hollow ball ,h is mounted on the end of a rod which slides vertically in guides1 not shown4 ,adjustable stops ,s ,s press against a spring arm ,r1 pressing it up or down1 according as the water level is rising or falling4 ,if rising1 ,r makes contact with the adjustable screw ,a1 if falling1 with ,d1 in both cases completing the electrical circuit of the battery ,c and bell ,b4 ,illustration3 ,,fig4 #da ,another and simpler form is shown in ,fig4 #db1 where the ball ,h is mounted on the end of a lever ,l pivoted at ,p1 its rise or fall completing the circuit of ,b and ,c as before4 ,where it is desired to give a different signal for the rise and the fall of level1 two bells ,b and ,e 7,fig4 #dc7 may be used connected as shown4 ,the rising of the ball will ring bell ,b1 and its fall1 bell ,e4 ,illustration3 ,,fig4 #db ,,fig4 #dc ,in both forms of indicator1 a means must be provided that an undue rise may not bend the lever4 ,this may be accomplished by using contact springs instead of contact screws2 it is1 however1 then harder to adjust the indicator to fine differences of level4 ,in all cases the contacts must be faced with platinum to prevent corrosion4 ,burglar ,alarms4 ,a burglar alarm is a device for indicating the opening of a door or window1 by the ringing of a bell or operation of an annunciator4 ,the contact apparatus at the points to be protected may either open an electrical circuit or close one1 in the latter case being mere modifications of push buttons4 ,the simplest form is the latter or open-circuit method4 ,the spring contact to be inserted in the door jamb or window frame is so constructed that while under pressure the contacts are kept apart and the circuit is open4 ,but when the door or window is opened1 the pressure is released and a spring forces the contacts together4 ,fig4 #dd is an open-circuit window spring fitted in the window frame so that when the window is closed the spring lug ,s is pressed inwards1 breaking contact with the base ,b4 ,if the window is raised1 the lug flies to the position shown by the dotted lines1 and making contact with ,b1 completes the circuit through bell and battery4 ,these springs are fitted in the side of the window frame in a vertical position and are entirely concealed when the window is shut4 ,illustration3 ,,fig4 #dd ,in the closed-circuit system the reverse happens4 ,the pressure of the closed door or window keeps the contacts together and its opening enables them to spring apart4 ,illustration3 ,,fig4 #de ,in ,fig4 #de is a diagram of a closed-circuit burglar alarm1 ,c a cell of gravity battery1 ,r a relay1 ,f the fixed contact and ,m the movable contact of the spring1 ,s a stud projecting through the base of the spring and pushed in by the closed door4 ,when the door is closed1 ,s being pushed in1 the circuit of ,c1 ,r1 ,f and ,m is closed4 ,the magnets of the relay hold the armature arm ,a forward against a hard rubber contact4 ,but when ,s is released1 the relay circuit is opened1 ,r loses its power and ,a flies back1 making contact1 and throwing in circuit bell ,b and battery ,l4 ,illustration3 ,,fig4 #df ,a form of bell and relay combined is shown in ,fig4 #df4 ,here the armature ,a is held against the magnets while the circuit through the spring ,f and battery ,g is closed4 ,but on opening this circuit the armature flies back and makes contact with an adjustable contact screw ,s putting in circuit a local battery ,c4 ,the bell is now practically a vibrating bell2 on a closed circuit it rings until the circuit is again closed or the battery runs down4 ,illustration3 ,,fig4 #dg ,a different connection of the same scheme is ,fig4 #dg1 where only one battery is used4 ,this must be a gravity battery or some other closed-circuit battery4 ,the circuit can be easily traced in the figure and needs no special description4 ,both of the latter schemes are inferior to one using a separate relay4 ,if the circuit at the spring were quickly closed again the bell would either stop ringing1 or be so hampered as to ring very weakly4 ,illustration3 ,,fig4 #dh ,a relay made as in ,fig4 #dh has no spring support to the armature ,a1 which falls down by gravity4 ,the adjustable contact ,c is screwed far back1 so that the armature must fall a considerable distance away from the electromagnets before it makes contact4 ,this ensures that the armature will not be attracted and the bell stopped from ringing by a re-closing of the circuit at the door or window spring4 ,a shade spring 7,fig4 #di71 is made for either open or closed circuits4 ,in operation1 the shade is pulled down and its string or ring hooked on to ,h4 ,this draws ,h up a trifle against a spiral spring and its lower end makes contact with an insulated spring ,s closing the circuit4 ,if the shade is disturbed1 the spiral spring on the lower part of ,h is released and it causes a break of contact with ,s in the direction of the arrow4 ,illustration3 ,,fig4 #di ,when made for open circuit1 ,s is bent so that while under tension no contact is made1 but release of tension causes the contact4 ,fig4 #ej gives the wiring of two windows and a door on the closed-circuit system4 ,it will be seen that the contact springs are all in series1 opening a window or the door will thus break the circuit4 ,when setting the alarm at night by connecting up the batteries1 relay and bell1 should any one of these springs be open the relay armature will not hold1 and the bell rings4 ,illustration3 ,,fig4 #ej ,in this figure the relay is replaced by an electromagnet holding up a drop shutter by magnetic attraction4 ,upon the circuit opening1 this shutter falls1 exposing a number painted on it4 ,at the same time it hits a spring contact placed below it and closes the bell and local battery circuit4 ,door ,trip ,alarm4 ,a swinging contact door trip can be attached over a door to ring a bell when the door is opened4 ,illustration3 ,,fig4 #ea ,in ,fig4 #ea the door trip is screwed over the door so that the lowest arm ,a is struck by the door4 ,when the door is opened1 in the direction of the arrow1 the arm ,a is thrust forwards1 and in its turn moves the contact arm ,c1 completing the bell and battery circuit4 ,but when the door is being closed1 ,a swinging in the reverse direction does not move ,c and no alarm is given4 ,miscellaneous ,alarms4 ,the ,applegate electrical matting is composed of wooden slats with springs so arranged that the weight of any person stepping on it will close a circuit and ring a bell4 ,it is intended to be put under the ordinary door mat or under stair and room carpeting4 ,the ,yale lock switch is a ,yale lock and switch combined4 ,upon any key but the right one being inserted1 a circuit is closed and an alarm bell is rung4 ,,chapter ,v ,annunciators ,the ,annunciator4 ,the mechanism of an annunciator consists of electromagnets which allow shutters to drop or needles to move on the circuits being closed4 ,a bell is also rung in most cases to call attention to the annunciator4 ,the number of the circuit is marked on the shutter1 or near the needle1 either shutter or needle being replaced by a reset device1 which may be mechanical or electrical4 ,illustration3 ,,fig4 #eb ,annunciator drops are made in a variety of forms4 ,fig4 #eb illustrates the principle underlying nearly all of them4 ,when current flows through the magnet coils ,m1 the armature ,a is attracted1 and being pivoted at ,p1 the lever hook ,h rises and allows the weighted shutter ,s to fall and display a number painted on its inside surface4 ,illustration3 ,,fig4 #ec ,,fig4 #ed ,the needle drop in ,fig4 #ec is one that has met with great favor and works as follows3 the soft iron core of the magnet ,c has a hole drilled through it1 in which turns the shaft ,s4 ,an arrow or needle is attached at the front end over the face of the annunciator4 ,a notched arm ,b is fixed on the rear end of the shaft and is held in a horizontal position by the end of armature ,a4 ,when the current flows around ,c1 armature ,a turns on its pivot towards the core of ,c1 as in ,fig4 #ed1 unlocking ,b1 which falls and thereby partly rotates shaft ,s and the arrow4 ,when it is desired to reset the arrow and arm1 a button is pressed upwards1 which raises a rod carrying an arm ,r4 ,this latter arm in turn raises ,b to its former position1 the heavy end of ,a falls1 and its pointed end locks ,b4 ,illustration3 ,,fig4 #ee ,pendulum1 or swinging1 signals are used in annunciator work1 where there is a liability that the ordinary drop shutter would not be reset4 ,they1 however1 only give a visible signal for a few seconds1 and are therefore liable to be overlooked4 ,in ,fig4 #ee a pivoted arm carrying a soft iron armature ,a and a thin plate ,b having a number on it is free to swing in front of an electromagnet ,m4 ,when the current flows in the electromagnet the armature is attracted1 and upon the circuit being broken at the push1 the armature is released and the arm swings to and fro4 ,the drops of an annunciator are wired up as in ,fig4 #ef4 ,illustration3 ,,fig4 #ef ,one end of each coil is attached to a common return wire ,c1 the other end going to the push ,p4 ,when ,p is depressed1 the circuit of any drop is through ,m along ,c through bell1 battery and up common battery wire ,w back to other contact of push ,p4 ,depressing any push does not therefore affect any other drop but the one controlled by it4 ,wiring up an ,annunciator4 ,a diagram of the connections for an annunciator with a separate bell is given in ,fig4 #eg4 ,where the bell is contained in the case a terminal will be generally found for connection4 ,illustration3 ,,fig4 #eg ,the figure shows a wire running from the battery to one side of each push button4 ,this is the common return1 or battery wire1 and saves installing two wires from each push4 ,it should be larger1 however1 than the rest of the wires1 generally about ,no4 #af ,b4 ,s4 ,all the wires for an annunciator should be run before connecting up4 ,there are different methods of sorting out the wires at the annunciator4 ,one way is to connect the wires 7except of course common or battery return wires7 to the drops in any order4 ,then an assistant travels from push to push and presses each button1 noting the room numbers and the order in which they were visited4 ,as each drop falls1 its number and order is noted4 ,comparing this with the list made by the assistant will show the correct changes to make4 ,illustration3 ,,fig4 #eh ,for instance1 suppose pushes #a1 #b1 #c1 #d1 #e and #f were pressed in that order1 and drops #c1 #d1 #e1 #a1 #b and #f fell in that order4 ,then the wires at the annunciator would be changed as follows3 ,from #c to #a1 #d to #b1 #e to #c1 #a to #d1 and #b to #e2 #f would already be in its right place4 ,another way is to commence by twisting together say the wires at ,no4 #a push4 ,then go to the annunciator and touch each of the push wires to ,no4 #a drop until it falls4 ,then connect it1 untwist the wires at ,no4 #a1 push and connect it up4 ,proceed to ,no4 #b and so on until all the pushes have been connected in turn4 ,in some cases it is desired to answer back to the person calling1 or to be able to call any person from the annunciator4 ,a circuit like ,fig4 #eh answers the purpose of both annunciator call and return1 or fire1 call4 ,this requires two wires from each room to the annunciator and a common return wire4 ,by tracing out the circuit it will be seen that when a room push is pressed1 the annunciator needle and bell indicate4 ,and when one of the pushes near the annunciator is pressed1 the corresponding room bell rings4 ,the former circuit is from the push1 along the common return wire1 through bell and annunciator back to the push4 ,the fire call is from push up line to bell through bell along common return and through battery to the push4 ,the ,western ,electric single-wire system 7,fig4 #ei7 uses three-point pushes1 two batteries and two return wires4 ,battery ,a is for the annunciator circuit and battery ,f for the fire1 or return1 call4 ,illustration3 ,,fig4 #ei ,in each room the top contact and push spring contact are normally together4 ,if one of the pushes below the annunciator is pressed1 battery ,f is thrown in series with the bell in the room4 ,but when the room push is pressed its bell is cut out and the circuit becomes like an ordinary annunciator circuit4 ,,chapter ,,vi ,annunciators and ,alarms ,three ,wire ,return ,call ,system4 ,a three wire return call annunciator system is shown in ,fig4 #fj4 ,there are two battery wires installed1 from which taps are taken off and led to each room or push button4 ,three way or return call push buttons are used as shown at points marked ,b4 ,in the diagram1 the bells are marked ,a1 the drops in the annunciator ,d1 the annunciator bell ,c and the return call buttons in the annunciator ,e4 ,the batteries are as shown at ,f4 ,the heavy black outline encloses the annunciator mechanism and connections which are drawn diagrammatically for the sake of clearness4 ,three stations only are shown on the sketch1 but the annunciators which are manufactured by ,edwards and ,co41 ,inc41 of ,new ,york1 are made in all standard sizes4 ,installing ,elevator ,annunciators4 ,the installing of electric bells and annunciators in elevators does not present any special problems1 although the apparatus used must be selected with a view to its being suitable to withstand the shocks incident to elevator service4 ,illustration3 ,,fig4 #fj ,in general the wires leading from the push buttons on the different floors to the bell or annunciator in the elevator1 are flexible and made up into a cable4 ,one end of this cable is attached to the underside of the elevator car1 the other end being fixed usually to the elevator wall1 at a point midway between the top and bottom of the shaft4 ,in ,fig4 #fa is shown a diagram of the general circuit used1 details of course differing in each installation4 ,one point to be taken care of in elevator work is the attachment of the cables4 ,the continual movement tends to break the wires at the two ends if good flexible cable is not used and the installation done in a workmanlike manner4 ,elevator cable is a standard article and may be procured through any electrical supply store4 ,that most commonly used consists of the requisite number of copper conductors each composed of #af strands ,no4 #cj ,b4 and ,s4 gauge soft and untinned copper wire4 ,these flexible conductors are insulated with two reverse wrappings of cotton and one braid of cotton4 ,the insulated conductors are cabled together with a steel supporting strand where extra tensile strength is required1 as in the case of extra long cables4 ,the number of conductors generally ranges from #c to #bj inclusive4 ,the wires leading from the push buttons to the cable should be preferably rubber covered and braided4 ,only where economy at the outset is desired may ordinary annunciator or office wires be employed4 ,illustration3 ,,fig4 #fa ,a connection block carrying binding posts is used at each point where the cable connects to the push button wires or to the annunciator4 ,this may be home-made or purchased ready made1 as desired4 ,burglar ,alarm ,annunciators4 ,although almost any annunciator may be used for open circuit burglar alarm work1 they usually do not contain certain devices which are desirable in burglar alarm work4 ,in ,fig4 #fb is shown a diagram of a burglar alarm annunciator1 the view being schematic of the back board4 ,the references are as follows3 ,a is the main alarm bell situated wherever desired and connected to the binding posts ,,bb4 ,the battery connection leading directly to the battery ,k is marked ,c and that leading to the contact spring is marked ,d4 ,the cut-off switch ,e cuts off the battery while ,f is the constant ring switch4 ,g is the upper bar and ,h the lower bar1 while the letters ,,jj denote the indicating drops4 ,the door and window springs are lettered ,s4 ,at ,l is a switch which may be used to disconnect the entire burglar alarm system4 ,where it is desired to disconnect only a section at a time1 the switch corresponding to the section is turned off the upper bar ,g and on to the lower bar ,h4 ,illustration3 ,,fig4 #fb ,clock ,alarm ,circuit4 ,a diagram of the wiring and connections on the back board of all clock alarms is illustrated in ,fig4 #fc4 ,this diagram embodies the principles of the last described circuit1 but includes the circuit of a clock-operated alarm4 ,bells for ,high ,voltages4 ,the use of electric bells on lighting circuits is becoming quite general1 as it obviates the necessity of using batteries1 and thereby simplifies both installation and maintenance4 ,there is no fundamental objection to operating make and break bells on electric light circuits4 ,providing the voltage and amperage are the same1 there is little difference between the current from a direct-current dynamo and that from a battery4 ,but owing to the higher voltages of the lighting circuit over that generally employed from batteries1 the bell coils must be wound to high resistances to keep down the current strength4 ,there are also other slight changes to assist in suppressing sparking1 as have been already treated on4 ,where the circuit is not over #bbj volts1 the bells are wound with fine wire and have also self-contained resistance coils4 ,for #ejj volts and over1 a resistance lamp is connected in with the bell which in this case is wound for a #aej-volt circuit4 ,these bells up to #f-;inch and inclusive will operate on circuits of either direct or alternating current4 ,above this size it is necessary to use specially constructed bells on alternating current circuits4 ,illustration3 ,,fig4 #fc ,most large hotels and office buildings having direct current lighting service are using it for ringing bells and similar work to the total exclusion of batteries4 ,where the number of units to be operated justifies it1 motor generators are operated in connection with the lighting mains to produce a low voltage most suitable for the bells4 ,the connections in this case are no different to those when batteries are employed4 ,bell-ringing ,transformers4 ,the best system for operating bells and annunciators from alternating current circuits is undoubtedly that employing small specially constructed transformers to reduce the voltage4 ,these transformers are being used universally for hotel and office work where alternating current is available4 ,they are simple1 being merely one or more coils of well insulated wire wound on soft iron cores and having connections for both the lighting circuit and the bell circuit4 ,as a general rule the coils are divided as to their number of turns or according to the ratio of transformation desired4 ,for example1 if the circuit were #aaj volts and #aj volts was required for the bell circuit1 the total number of turns in the transformer would be connected1 #aj_/aa to the lighting circuit and #a_/aa to the bell circuit4 ,the bell-ringing transformers on the market are made in several styles4 ,one small style1 ,fig4 #fd1 for single residences1 is for use on #aaj volts and produces a bell voltage or secondary voltage as it is termed1 of #f volts4 ,another size1 ,fig4 #fe1 of this transformer has three secondary voltages #f1 #ab and #ah1 each of which can be used by connecting to the right binding posts4 ,illustration3 ,,fig4 #fd ,,fig4 #fe ,,bell-,,ringing ,,transformers4 ,it is to be noted that where the lighting service voltage or primary voltage varies from the above1 the secondary voltage delivered to the bell circuit will vary in like proportion4 ,it should also be noted that a careless reversing of the connections1 that is connecting the secondary leads to the lighting circuits1 instead of the primary leads would cause a like high voltage at the other terminals of the transformer1 raising it in due proportion instead of lowering it4 ,thus such carelessness would produce a voltage of #b1djj volts instead of #f if a transformer intended to deliver #f volts from a #abj-volt circuit was wrongly connected4 ,the results might very well then be dangerous4 ,all transformers are properly marked1 however1 and such an error only occurs through ignorance or carelessness4 ,the installation of these bell-ringing transformers is simplicity itself2 they require no care after installation and have met with the approval of the ,national ,board of ,fire ,underwriters4 ,combination ,circuits4 ,circuits intended primarily for electric bells or annunciators in houses and apartments may often be also made to serve for other electrical devices such as door openers1 house telephones1 etc4 ,this subsidiary apparatus may be installed with a little additional wiring or perhaps will not need any other wires1 as when both the devices are not used at once4 ,illustration3 ,,fig4 #ff ,electrical door openers are great conveniences and are practically indispensable where the outside door is on another level to the location of the dweller or where two or more families occupy the same house4 ,the device is simple1 consisting of an electrically released spring-plate against which the lock bolt is normally held and a door opening spring4 ,when the door opener button is pressed1 the spring plate is released1 releasing the lock bolt by the same action4 ,the door spring then forces the door open enough to clear the opener plate1 which flies back into position when the button is released4 ,these door openers are made in several forms for door frames1 such as those on thin doors1 iron gates1 for surface or rim locks1 for thick doors1 sliding doors and any other regular type of door4 ,the push button is the same as used for electric bells and may be located wherever desired4 ,the pushes are wired in multiple as shown in ,figs4 #ff and #fg1 which are two circuits of a type of the ,western ,electric interphone1 a system of house telephones supplied for houses and buildings of every size4 ,fig4 #ff shows a circuit which provides telephone service between the vestibule and the apartments1 the door opener wiring being clearly indicated4 ,in ,fig4 #fg the circuit provides a more extensive service1 enabling the janitor1 the apartments and the tradesmen to intercommunicate in the most desirable system4 ,the door opener wiring is also clearly shown4 ,illustration3 ,,fig4 #fg ,the convenience of having telephone connection in the house or hotel and its advantages over speaking tubes are too well known to need extended comment4 ,where electric bells have already been installed it is quite feasible now to use the same wires for telephones also4 ,telephone sets especially designed for this service are manufactured by the ,western ,electric ,company in their interphone series4 ,they are simple and compact1 and may be installed by anyone who can put up an electric bell4 ,fire ,alarm ,circuits4 ,a fire alarm circuit suitable for factories1 private plants or groups of buildings is shown in ,fig4 #fh4 ,it is a series system1 with closed circuit1 the gongs sounding whenever the circuit is opened whether by the contact breaker in the boxes or by the accidental breaking of a wire4 ,this insures that it remains in good working order1 as when any part of the circuit is opened1 a warning tap is sounded on every bell or gong4 ,the boxes have contact breakers which send a separate number of impulses for each box1 thus announcing the box number on each gong4 ,the boxes and gongs may be located anywhere1 as the system is perfectly flexible4 ,the reference letters in the diagram are as follows3 ,c indicates the gongs which are preferably of the electro-mechanical type1 a coiled spring providing force for the blow1 electricity being merely used to release and retain the hammer or striker4 ,the alarm boxes are marked ,,bb and the battery which is of the closed circuit type is marked ,d4 ,illustration3 ,,fig4 #fh ,interior ,fire ,alarm ,system4 ,another system suitable more particularly for indoor operation is illustrated in ,fig4 #fi4 ,here the alarm is given by breaking the glass front of an alarm box and releasing or pressing an electrical contact4 ,the box sounded indicates by causing a drop to fall on an annunciator and at the same time rings an alarm bell4 ,the latter are generally provided with constant ring attachments1 which keep the bell sounding until shut off4 ,the annunciator shown in the diagram has switches for controlling each individual bell circuit1 and also for control of the entire system4 ,there is no practical limit to the number of stations in this system1 it being determined by the size of the annunciator used or by other obvious factors4 ,the reference letters on the diagram are as follows3 ,a1 alarm bells which may be located wherever desired4 ,b1 break-glass alarm boxes also located at convenient points4 ,c1 annunciator drops1 ,d1 switches on annunciator which control each individual bell circuit1 enabling any circuit to be cut out1 cut in or tested without disturbing any other circuit4 ,e is a general alarm switch1 causing all bells to ring at once when it is operated4 ,the battery ,f varies with the number of bells and boxes and the length of line1 from three cells upwards4 ,a cut-out switch ,h is added to cut out the entire system by opening the battery wire4 ,the annunciator bell is at ,i1 an auxiliary bell being added in multiple with it when necessary4 ,illustration3 ,,fig4 #fi ,illustration3 ,,fig4 #gj ,fire ,alarm ,system for ,considerable ,areas4 ,where the area is more extensive and the number of stations considerable1 the system illustrated in ,fig4 #gj is very suitable4 ,it consists of the requisite number of break-glass boxes1 bells and a more elaborate annunciator system4 ,in general details it resembles the last system1 but uses a relay to send out the current for ringing the alarm bells4 ,when a box operates1 the current impulses sent on the line act on the relay instead of directly on the bells4 ,each stroke of the relay closes a local circuit which includes the bells and the battery4 ,this system does away with large batteries and is very economical of wire4 ,the current needed for the relay is very small1 whereas in a direct system of any size1 the current and voltage to ring a number of bells located at wide intervals would be prohibitive4 ,the reference letters are as follows3 ,,aa are the alarm bells1 ,,bb the break-glass alarm boxes1 ,c is the annunciator bell1 ,d is the relay which remains closed when an alarm comes in keeping the bells constantly ringing until shut off4 ,e is a resistance coil and ,f is the battery4 ,a system cut-out switch ,g and ,,jj switches on the annunciator for controlling individual circuits are also provided4 ,,hh are the annunciator drops and ,k is a constant-ring switch which can also be used for a general alarm to ring all the bells at once4 ,,learn ,,to ,,do ,,things ,model ,library ,series ,,of ,,copyrighted ,,books #a4 ,the ,study of ,electricity for ,beginners4 #b4 ,dry ,batteries1 ,how to ,make them4 99 #c4 ,electrical ,circuits and ,diagrams1 ,part #a4 #d4 ,electric ,bells1 ,annunciators and ,alarms4 #e4 ,modern ,primary ,batteries4 #f4 ,experimenting with ,induction ,coils4 99 #g4 ,electric ,gas ,igniting ,apparatus4 99 #h4 ,small ,accumulators1 ,how to ,make and ,use4 #i4 ,model ,steam ,engine ,design4 99 #aj4 ,practical ,electrics4 #aa4 ,inventions1 ,how to ,protect and ,sell them4 #ab4 ,woodwork ,joints1 ,how to ,make and ,use4 99 #ac4 ,the ,fireman's ,guide to the ,care of ,boilers4 99 #ad4 ,the ,slide ,valve ,simply ,explained4 99 #ae4 ,the ,magneto ,telephone4 99 #af4 ,the ,corliss ,engine and ,its ,management4 99 #ag4 ,making ,wireless ,outfits4 #ah4 ,wireless ,telephone ,construction4 99 #ai4 ,the ,wimshurst ,machine1 ,how to ,make ,it4 #bj4 ,simple ,experiments in ,static ,electricity4 #ba4 ,small ,electrical ,measuring ,instruments4 #bb4 ,electrical ,circuits and ,diagrams1 ,part #b4 99 #bc4 ,induction ,coils1 ,how to ,make ,them4 #bd4 ,model ,vaudeville ,theatres4 99 #be4 ,alternating ,currents1 ,simply ,explained4 99 #bf4 ,how to ,build a #bj foot ,bi-plane ,glider4 99 #bg4 ,a ,b ,c of the ,steam ,engine4 99 #bh4 ,simple ,soldering1 ,hard and ,soft4 99 #bi4 ,telegraphy for ,beginners4 #cj4 ,low ,voltage ,lighting with ,storage ,batteries4 #cc4 ,house ,wiring for ,electric ,light4 #cd4 ,magnets and ,magnetism4 99 #cf4 ,small ,windmills and ,how to ,make ,them4 ,injectors1 ,their ,construction and ,use4 ,keppy4 ,refrigeration and ,ice ,making4 ,wakeman4 #cg4 ,collin's ,wireless ,plans1 ,part #a4 #ch4 ,collin's ,wireless ,plans1 ,part #b4 ,in paper covers ,price #be;c each postpaid4 99,these books can also be had in cloth binding at #ee;c each postpaid4 ,dubelle's ,famous ,formulas4 ,,known ,,as ,non ,plus ,ultra ,soda ,fountain ,requisites of ,modern ,times ,by ,g4 ,h4 ,,dubelle4 ,a practical ,receipt ,book for ,druggists1 ,chemists1 ,confectioners and ,venders of ,soda ,water4 ,,synopsis ,,of ,,contents4 ,,introduction4--,notes on natural fruit juices and improved methods for their preparation4 ,selecting the fruit4 ,washing and pressing the fruit4 ,treating the juice4 ,natural fruit syrups and mode of preparation4 ,simple or stock syrups4 ,,formulas4 ,,fruit ,,syrups4--,blackberry1 black current1 black raspberry1 catawba1 cherry1 concord grape1 cranberry1 lime1 peach1 pineapple1 plum1 quince1 raspberry1 red current1 red orange1 scuppernong grape1 strawberry1 wild grape4 ,,new ,,improved ,,artificial ,,fruit ,,syrups--,apple1 apricot1 banana1 bitter orange1 blackberry1 black current1 cherry1 citron1 curacoa1 grape1 groseille1 lemon1 lime1 mandarin1 mulberry1 nectarine1 peach1 pear1 pineapple1 plum1 quince1 raspberry1 red current1 strawberry1 sweet orange1 tangerine1 vanilla4 ,,fancy ,,soda ,,fountain ,,syrups4--,ambrosia1 capillaire1 coca-kina1 coca vanilla1 coca-vino1 excelsior1 imperial1 kola coca1 kola-kina1 kola-vanilla1 kola-vino1 nectar1 noyean1 orgeat1 sherbet1 syrup of roses1 syrup of violets4 ,,artificial ,,fruit ,,essences4--,apple1 apricot1 banana1 bergamot1 blackberry1 black cherry1 black currant1 blueberry1 citron1 cranberry1 gooseberry1 grape1 lemon1 lime fruit1 melon1 nectarine1 orange1 peach1 pear1 pineapple1 plum1 quince1 raspberry1 red currant1 strawberry4 ,,concentrated ,,fruit ,,phosphates4 ,acid solution of phosphate1 strawberry1 tangerine1 wild cherry4--#bi different formulas4 ,,new ,,malt ,,phosphates--#cf4 ,,foreign ,,and ,,domestic ,,wine ,,phosphates--#i4 ,,cream-,,fruit ,,lactarts--#bh4 ,,soluble ,,flavoring ,,extracts ,,and ,,essences--#ad4 ,,new ,,modern ,,punches--#ah4 ,,milk ,,punches--#ag4 ,,fruit ,,punches--#cb4 ,,fruit ,,meads--#ah4 ,,new ,,fruit ,,champagnes--#ag4 ,,new ,,egg ,,phosphates--#ad4 ,,fruit ,,juice ,,shakes--#bd4 ,,egg ,,phosphate ,,shakes4 ,,hot ,,egg ,,phosphate ,,shakes4 ,,wine ,,bitter ,,shakes--#ab4 ,,soluble ,,wine ,,bitters ,,extracts--#ab4 ,,new ,,italian ,,lemonades--#ah4 ,,ice ,,cream ,,sodas--#ci4 ,,non-,,poisonous ,,colors4 ,,foam ,,preparations4 ,,miscellaneous ,,formulas--#bf4 ,,latest ,,novelties ,,in ,,soda ,,fountain ,,mixtures--#g4 ,,tonics4--,beef1 iron and cinchona2 hypophosphite2 beef and coca2 beef1 wine and iron2 beef1 wine1 iron and cinchona2 coca and calisaya4 ,,lactarts4--,imperial tea2 mocha coffee2 nectar2 ,persian sherbert4 ,,punches4 ,,extracts4--,columbia root beer2 ginger tonic2 soluble hop ale4 ,,lemonades4--,french2 ,vienna4 ,egg nogg4 ,hop ale4 ,hot tom4 ,malt wine4 ,sherry cobbler4 ,saratoga milk shake4 ,pancretin and wine4 ,kola-coco cordial4 ,iron malt phosphate4 ,pepsin1 wine and iron1 etc4 #aeg ,pages1 ,nearly #ejj ,formulas4 #abmo41 ,cloth1 #a4jj ,a ,,new ,,american ,,book ,,on ,,industrial ,,alcohol4 ,a ,,practical ,,handbook ,,on ,,the ,distillation of ,alcohol ,,from ,,farm ,,products ,,and ,,de-,,naturing ,,alcohol4 ,by ,f4 ,b4 ,,wright4 ,including the ,free ,alcohol ,law and its ,amendment1 the ,government regulations therefore and a number of ,u4 ,s4 government authorized de-naturing formulas4 ,in the preparation of this1 the second edition1 the author has followed his original plan of writing a plain practical handbook on the manufacture of alcohol and de-naturing for industrial purposes4 ,this industry is bound to grow to enormous proportions as it has in ,germany where over #ajj1jjj1jjj gallons were manufactured last year principally in small farm distilleries4 ,this work is not intended as a scientific treatise but as a help to farmers and others wishing to go into this industry on a moderate scale4 ,the original matter has been carefully revised4 ,some of the chapters rewritten and a very considerable amount of new information added4 ,the total number of illustrations brought up to #fj including a number of plates giving the layout of distilleries4 ,contents of ,chapters4 #a1 ,alcohol1 its various forms and sources4 #b1 ,the preparation of mashes and ,fermentation4 #c1 ,simple ,distilling ,apparatus4 #d1 ,modern ,distilling ,apparatus4 #e1 ,rectification4 #f1 ,malting4 #g1 ,alcohol from ,potatoes4 #h1 ,alcohol from ,grain1 ,corn1 ,wheat1 ,rice and other ,cereals4 #i1 ,alcohol from ,beets4 #aj1 ,alcohol from ,molasses and ,sugar ,cane4 #aa1 ,alcoholometry4 #ab1 ,distilling ,plants4 ,their general arrangement and equipment4 #ac1 ,de-natured ,alcohol and ,u4 ,s4 ,authorized ,de-naturing ,formulae4 #ad1 ,de-naturing ,regulations in the ,united ,states4 ,index4 #bha pages1 #fj illustrations and plates1 #abmo41 cloth1 #a4jj4 ,illustration ,send for this to-day ,fourth ,edition1 ,enlarged ,,revised ,,and ,,rewritten ,,electrical ,,testing ,,by ,,norman ,h4 ,,schneider ,contents of ,chapters4 #a4 and #b4 ,galvanometers4 #c4 ,rheostats1 keys and shunts4 #d4 ,voltmeters and ammeters4 #e4 ,the ,wheatstone bridge4 #f4 ,portable testing sets4 #g4 ,testing with the galvanometer4 #h4 ,the ,potentiometer4 #i4 ,condensers4 #aj4 ,cable testing4 #aa4 ,testing with the voltmeter4 #ab4 ,testing telephone lines4 #ac4 ,testing telegraph wires and cables4 #ad4 ,locating faults in telegraph and telephone cables4 ,tables2 ,index2 with numerous practical illustrations worked out4 #cad pages1 #aej illustrations1 cloth #a4ae postpaid4 ,spon ,chamberlain1 #abc-e ,,liberty ,,street1 ,,new ,,york ,transcriber's ,notes ,punctuation and spelling were made consistent when a predominant preference was found in this book2 otherwise they were not changed4 ,simple typographical errors were corrected4 ,occurrences of inconsistent hyphenation have not been changed4