is nothing quite so green as this shaft of light when the copper electrode is fusing. As soon as this shaft of green light is observed by the engineer he must immediately reduce the speed of the armature by closing in on the throttle to turbine until a shaft of white light is produced. Another way in which a green light may be produced other than by excessive speed of the armature fusing the copper electrode is by the positive wire being connected to the negative binding post, either at the dynamo or the lamp, in which case the current would enter the copper electrode first and a green light would be produced, because the arc is always produced in the point which the current enters first, and in entering the copper electrode first the copper would be fused. When crossed wires are responsible for the production of the green light the wire connections at the binding posts either at the dynamo or the lamp must be changed in order to introduce the current into the top carbon first and produce the white light. The engineer may know whether the green light is caused by excessive speed of the armature or by crossed wires because if the light comes up white and then turns to green it is caused by high speed of the armature, while if the light is green the instant it appears the cause of the trouble is to be found in crossed wires. 12. Wiring for Cab Lights.-The best method of wiring the cab of a locomotive for the gauge and water glass lamps to avoid future trouble is to run the wires from the dynamo into the cab through an iron pipe or a piece of circular loom conduit and under a molding in the top of the cab. Should the iron pipe be used, the wires must be carefully wrapped with insulation tape where they enter and leave the pipe. 13. What to Look Out for Before Starting on a Trip.-In order to know that his electric headlight is in good working condition before starting out on a trip the engineer must follow these instructions to the letter: First, the water of condensation should be drained from the oil cellar in the engine cap and this bearing should be oiled with cylinder oil. Second, see if the loose ring which is suspended by the shaft and in the oil cellar of the main bearing touches the oil, and if it does not, enough engine oil should be introduced into the cellar so that this oil ring will trail through the oil. Third, see that the commutator is mechanically clean and that the mica strips between the commutator bars are below the surface of the bars. Fourth, see that the brushes are perfectly free in the holders, are not stuck or even tight, and that they have a good bearing. Fifth, be sure to note if both of the main wires are held securely in the binding posts, and that the binding post screws are tight against the wires both at the dynamo and the lamp. Sixth, be careful to examine where the wires may enter or leave the pipes or the hand railing, the headlight case and the cab, and know without doubt that the insulation is in good condition on all wires, both in and out of the cab. Seventh, see that the carbon in the lamp is of sufficient length to make the trip, and that the clutch will lift the carbon at least of an inch from the point of the copper electrode. Eighth, be careful to note if the point of the copper electrode is clean and that it is pointed up with of an inch surface on the point. Ninth, see that the copper electrode is not stuck in the holder. Tenth, be sure that the point of the copper electrode lines up true under the carbon. If the scale is left upon the point of the copper electrode and not cleaned off as directed, when the steam is turned on to start the dynamo in operation in almost every instance it will be found that the dynamo will not "build up" where series fields are used, for the reason that this scale will offer too great a resistance for the low current to pass through to complete the circuit and build up the magnetism. This scale should be cleaned from the entire copper electrode each time the point is cleaned off. If neglected and this scale is allowed to form, the electrode will become stuck fast in the holder in a very short time and the scale between the copper electrode and the holder will completely insulate the electrode from the holder, and it will not be possible to establish a circuit until the electrode is removed from the holder and the scale cleaned off. When, upon examination, we find that the commutator is clean and copper electrode and holder are free from scale, yet the dynamo refuses to build up, we can usually establish the circuit and bring up the light by holding a piece of carbon against both binding posts for a few seconds, either at the dynamo or the lamp. The reason the dynamo refuses to build up at such times without bridging across the binding posts with a piece of carbon is that the resistance offered at the points of the carbons is too great for the weak current to pass through, but when you place the-carbon across the binding posts you cut out the point of great resistance or poor contact and form a good and direct path across from one binding post to the other, thus allowing the fields to build up at once, and when the carbon is removed from the binding posts the current will be found to be strong enough to pass through the point of great resistance or poor contact at the carbon points, and the light will come up. This only occurs with the series field and not with the compound fields. The strength of the solenoid is greatest when the arc is short, for the reason that there is less resistance offered to the passage of current from one carbon point to the other and there is more current circulating in the coils. It is very important that the engineer should know that the end of the lever, 59, is under the clutch rod weight, 78a, because if it was not the carbon could not be lifted and the lamp could not operate. It is also important to know that the thumb nut, 79, which secures the top carbon holder in the top bracket, 57, is tight, because should it work loose it would allow the top carbon holder to work loose and the carbon to drop by the point of the copper electrode, and a short circuit would result. 14. Applying New Carbons to Lamp. -After drawing carbons from the store room we should remove the top carbon holder from the lamp and try each of the carbons through the holder in order to ascertain if they will feed freely through the clutch when placed in the lamp. If we find a carbon that will not pass freely through the clutch it must be turned until a position is found where it will pass through. If it is found that this particular carbon will not pass through the clutch in any position without friction it should be thrown away and another one substituted in its place. No shadows are produced near the locomotive when the copper electrode is finished up with a surface of of an inch, and it is possible also to secure a better focus of the lamp, for the reason that with the of an inch surface a long arc is produced instead of a thin, flat arc, such as would be produced if the copper electrode was given of an inch surface. When it is found that the points of the carbon and the copper elec trode do not line up true, either the electrode holder or the top bracket which suspends the top carbon holder must be sprung until the carbon and copper electrode are brought in line with each other. Ordinarily it will be found that the lower, or copper, electrode holder is the one that is out of alignment, and should be bent to bring it under the carbon. For the reason that the electrode holder is made of brass and will bend very readily there is small danger of breaking it when bending to line up under the carbon. 15. Focusing the Lamp.-The condition of the reflector has a marked influence upon the light when the lamp is properly focused. It must be known that when the reflector is most highly polished the reflecting surface will absorb more or less of the light rays produced, but almost forty per cent. of the light will be lost if the reflector is in a dirty and unpolished condition. In order to get the lamp in perfect focus, first adjust the back of the reflector so that the front edge of the reflector and the front edge of the case will be parallel. Second, adjust the lamp so that the point of the copper electrode is as near the center of the reflector as possible. Third, have the carbons near the center of the chimney hole in the reflector. Fourth, have the engine on a piece of straight track not less than half a mile in length and move the lamp until you secure the best results on the track. The base of the lamp is provided with square holes through which the bolts are passed, and these holes are large enough to allow the lamp to be moved in any direction when focusing. In order to secure the proper vertical focus on the track, either to have the light strike the track far ahead or close to the locomotive, loosen the set screw, 74, on the side of the lamp column, and by turning the adjusting screw, 98, you can raise or lower the lamp, thereby throwing the light on the track where desired. This lamp may be moved sideways, backward and forward. In order to do this, loosen the hand nuts, 54, when the lamp can be moved freely. All screws must be tightened after the lamp is properly focused, as there will be no occasion to change it again. The back of the reflector is supported by an adjustable step which is provided with a screw for the purpose of raising or lowering, so that the entire volume of light will come from the reflector in par allel lines. The light should be reflected upon the track in parallel rays and in the smallest possible space. Raise the lamp to lower the light on the track. Lower the lamp in order to raise the light on the track. The lamp is not properly focused if it throws any shadows, as the light rays should be concentrated or drawn together, when there will be no shadows. In case the lamp is properly focused, that is, if all of the light rays leave the reflector in parallel lines and in a small pencil-like shaft, yet do not strike the center of the track, shift the entire case on the base board, but do not change the focus. The trouble is caused by the reflector case not being straight and parallel with the boiler. When it is desired to clean and polish the reflector, before attempting to remove the reflector from the case always remove the top guide, 100, by loosening the thumb nut, 79, and take out the top carbon holder. If these instructions are not followed it will be impossible to get the reflector out and the lamp will be damaged. This lamp can be focused by measurements in the most satisfactory manner. Following is the rule: You must know first that the reflector case sets straight and level on the arch of the locomotive, and that the front edge of the reflector is parallel with the front edge of the case. The center of the top of the copper electrode must be placed in the center of the reflector; the measurements must be taken from the top of the electrode to the sides, top and bottom of the reflector, then lower the electrode of an inch. If the reflector has a 16-inch face and is 8 inches deep, the copper electrode must be 23 inches from the back of the reflector. If the reflector has an 18-inch face and is 9 inches deep, the copper electrode must be 21 inches from the back of the reflector. If the reflector has an 18-inch face and is 12 inches deep, the copper electrode must be 1 inches from the back of the reflector. 16. Starting the Electric Headlight.When starting the electric headlight, the throttle to the steam turbine should be opened very slowly so that the water of condensation may pass out of the pipes and casting. This will also allow the steam to gradually heat the pipes and engine. By starting the equipment in this manner you not only heat up the pipes and engine, but your throttle opening will not be too large for the speed at which you may desire to run your dynamo when the water of condensation is carried off. Hence, if the governor valves were in need of attention and the steam was turned on rapidly with the throttle opened up wide, as soon as the water had passed out of the pipes and turbine engine the speed of the dynamo would become so great, and the electromotive force would be built up so high, that the copper electrode would be damaged. Examination Questions and Answers. OIL, ACETYLENE AND ELECTRIC HEAD LIGHTS. (Part 3, Section 1.) 1. Q.-What does the Pyle National Electric Headlight embody? A.-A self contained engine and dynamo and an arc lamp. (Art. 3.) 2. Q.-What are the principal parts of the dynamo? A. The armature with the commutator attached thereto, the two field magnets and the pole pieces. (Art. 3.) 3. Q.-What duty does the field coils or magnets perform? A. They produce a magnetic field in which the armature revolves. (Art. 3.) 4. Q.-What are the first three measurements of electricity? A. The volt, the ampere and the ohm. (Art. 4.) 5. Q.-What is the practical unit of measurement (a) of electrical pressure; (b) of the rate of flow of current; (c) of electrical resistance? A. (a) the volt; (b) the ampere; (c) the ohm. (Art. 4.) 6. Q.-For what purpose are the wires used for conducting electricity from the dynamo to the lamp insulated? A. To prevent the escape of the electricity. (Art. 5.) 7. Q.-What determines the amount of voltage produced? A.-The speed at which the armature revolves. (Art. 5.) 8. Q. How is a current of electricity made to perform work? A. By placing opposition in its path. (Art. 5.) circuits in the Pyle National Electric Headlight caused? A. By insulation of wires becoming distorted through chafing. (Art. 6.) A.-Would first start the dynamo with a good throttle opening and remove one 11. Q.-When is a circuit said to be of the main wires from the binding post closed? A. When it forms a continuous conducting path. (Art. 6.) 12. Q.-When is formed? an open circuit A. When a discontinuity occurs in such a manner that an electric current cannot flow. (Art. 6.) 13. Q.-If the electric headlight has been working perfectly while running along between stations, but the light suddenly begins to "jump and flash" very badly, what does it indicate? A. That there is an interruption in the flow of the current. (Art. 6.) 14. Q.-What would you do in case the light suddenly went out while running between stations and you could not at once look for the trouble? A.-Would turn off the steam to the turbine and stop the dynamo until I had an opportunity to locate the trouble; this in order to prevent any further damage being done to the equipment. (Art. 6.) 15. Q.-How would you distinguish between a short and an open circuit by the sound of the exhaust from the turbine. A. As a short circuit would allow all of the current to flow back into the armature without dissipating its pressure, thus leaving a very heavy current present in the coils, it would make a to pull, heavy load for the turbine which would slow same down; the speed of the turbine would decrease; the governor valve would open wide and a much greater volume of steam would pass through the wheel, thus causing a heavy, laboring sound heard at no other time; with an open circuit the dynamo would have no work to do and no load would be thrown upon the turbine, which being relieved of all load except that of turning the shaft and armature would race; the governor would force the governor valve into the seat of the steam supply to governor stand and very little steam would be allowed to pass from the exhaust pipe, and the noise made by its escape would be very light. (Art. 6.) 16. Q.-Where are short circuits in this device usually found? A.-Almost without exception in the wires leading to the cab lights or in the wires leading from the dynamo to the arc lamp. (Art. 6.) at the dynamo. If the machine continued to run slow the trouble would be in the dynamo, and must be looked after by the repairman. If upon removing one of the main wires in the binding post at the dynamo the speed of the dynamo instantly increased would know that the trouble was not in the turbine or the dynamo, but further on toward the lamp or in the cab circuit. Would return the main wire to the binding post at the dynamo and remove one of the main wires from either binding post at the lamp, and unless the speed of the dynamo instantly increased would know that the short circuit was to be found in the wires between the dynamo and the lamp. If, however, the speed of the dynamo increased upon removing the wire from the binding post at the lamp, would expect to find the thumb nut used to secure the top carbon holder to the bracket loosened so as to allow the point of the carbon to pass by the point of the copper electrode, or that the carbon was stuck fast in the clutch and against the point of the copper electrode. If, upon removing the wire from the binding post at the brush holder and cutting out the cab circuit the dynamo ran slow and labored heavily, would look for the trouble either in the turbine or the dynamo. If the turbine was responsible for the high speed and heavy load, would overcome it by oiling the bearing and adjusting the end thrust to a movement of 1/32 of an inch. If after doing this the turbine continued to labor heavily would expect to find a short circuit in the armature or field coils. (Art. 6.) 18. Q.-Is it likely that the governor valve being stuck shut could be mistaken for a short circuit? A.-No, because while the speed of the dynamo would be very low, in that case there would be very little steam escaping from the exhaust pipe and practically no (Art. 6.) noise would be made. 19. Q.-What would you do in case one of the main wires from the dynamo to the lamp which has been placed within the hand railing should break while out on the road? A.-Would pull both ends of the broken wire from the hand railing, strip back the insulation from the ends of the wires and twist same together securely, after which would wrap the exposed wire with anything available to form an insulation. (Art. 6.) 20. Q.-How is the speed of the turbine controlled? A. By a governor of the centrifugal form which is applied within the casing of the engine. (Art. 7.) 21. Q.-What other appliance is provided with the turbine to prevent the speed from attaining a velocity beyond that desired? A.-A centrifugal brake which is set to act at about 150 revolutions higher speed than that at which the governor is set to act. (Art. 7.) 22. Q.-Why is the centrifugal brake set to act at a higher rate of speed than is the governor? A. Because were the brake set to act in conjunction with the governor weights it would seriously interfere with the speed at the critical time, besides this brake was designed and applied to prevent any possibility of the turbine running away and being thrown to pieces by centrifugal force at times when the governor valves have been neglected. (Art. 7.) 23. Q.-What might occur should the governor valves stick open? A. A very high electro-motive force would be built up and the copper electrode and holder might be destroyed. (Art. 7.) 24. Q.-When the governor valves have correct travel and all parts are in good condition, how may the speed of the turbine and dynamo be increased or decreased? A. To increase the speed would move all of the adjusting screws, 117, of the governor springs to the right, and to decrease the speed would move them to the left. (Art. 7.) 25. Q.-If it is desired to increase or decrease the speed of the dynamo 100 revolutions per minute, how much of a movement would you give to the adjust ing screws, 117? A. To increase the speed 100 revolutions per minute would move them onehalf turn to the right, and to decrease the speed of the dynamo in the same proportion would move them one-half turn to the left. (Art. 7.) 26. Q. What might prevent the regulation of the speed of the dynamo by changing the adjustment of the governor spring screws? A.-Improper lubrication or lack of lubrication of the bearing in the engine cap, the end thrust being maintained too close or the sticking open or closed of one of the governor valves while the valve remained in such condition. (Art. 7.) 27. Q.-How would you adjust the centrifugal brake? A.-Would remove the armature, engine cap and governor and pull out the wheel and shaft, which would give free access to the brake. (Art. 7.) 28. Q.-How much would you move the adjusting nuts, 136, to increase or decrease the speed 150 revolutions at which the centrifugal brake would act? A. One-half turn either to the right or left. Would turn the nuts to the left to lower the speed and to the right to increase the speed. (Art. 7.) 29. Q.-How may the sticking of the governor valves be prevented? A.-By removing the -inch plug at the top of the engine casting each trip before starting the equipment and introducing a small amount of coal oil or black oil at that point; then when steam is turned into the turbine the oil will be blown through the governor stands and around the governor valves and would cut away any scale that might have started to form. (Art. 7.) 30. Q.-Should oil be introduced at the 4-inch plug at the top of engine casting for the purpose of lubricating the turbine or governor valves? A.-No. This turbine requires no internal lubrication for the reason that it has no reciprocating parts. (Art. 7.) 31. Q.-How many bearings has the turbine and where are they found? A.-Two, the shorter one being placed in the engine cap casting and supporting the weight of the turbine, the longer or main bearing being placed in the box yoke and carrying the weight of the armature. (Art. 7.) 32. Q.-Should the same grade of oil be used for both bearings in all cases? A. No, particularly in winter. Valve or cylinder oil should be used for the bearing in the engine cap on account of the heat in the engine cap and the presence of steam; it should always be oiled just before starting the equipment or at the beginning of each trip. For the main bearing the best results are usually obtained by the use of black or engine oil, as this bearing is always practically cold and an oil with a heavy body would be unable to pass through the long grooves in the bushing, but would drop back into |