The Traveling Engineers' Association Part 26

A. If you should fill the main oil cellar full of oil, the oil would run out of the overflow holes on the side and all over the equipment and locomotive and could do the dynamo no good but possibly harm.

40. Q. What is the most vital part of the dynamo?

A. The commutator.

41. Q. What care and attention should be given the commutator?

A. The commutator must be kept clean, free from dirt and grease; the mica must be kept filed down about one-sixty-fourth of an inch below the surface of the bars.

42. Q. How should you clean the commutator, and when?

A. The commutator should be cleaned before starting out on each trip by using a piece of damp waste, rubbing the bars lengthwise, then wipe dry with clean dry piece of waste.

43. Q. What kind of a bearing should the brush have on the commutator?

A. Brushes should be fitted to have a bearing with the same contour as the commutator, with bearing covering no less than two of the commutator bars, nor more than three of the bars.

44. Q. How are the brushes fitted?

A. Brushes are fitted by cutting a strip of No. O sandpaper about the width of the commutator surface. (Have the dynamo idle.) Place the strip of sandpaper under the brush on the commutator with the rough side towards the brush, then pull the sandpaper from right to left; continue this process until the brush has been fitted to a true smooth bearing.

Then trim about one-eighth of an inch off the front edge of the brush.

45. Q. Is it advisable to ever try to fit a brush up with a file or knife?

A. No.

46. Q. Why is it important to clean the scale off the point of the copper electrode each trip?

A. To allow the point of the carbon and the electrode to touch to form a circuit; this scale being a non-conductor of electricity and with it on, the current would not pa.s.s from the carbon to the electrode and holder.

47. Q. How should the copper electrode be trimmed at the point?

A. Copper electrode should have about 1/4-inch surface at contact point.

48. Q. How far should the copper electrode project above the holder?

A. One inch.

49. Q. Should the electrode be raised up to 1-1/2 inches, what might happen?

A. If the copper electrode was run at a point so near the clutch, the intense heat of the arc might do damage to the top carbon holder and clutch.

50. Q. If the dash pot should be found stuck, would you put oil in it?

A. Coal oil should be used to clean and cut the dirt out of the pot and from off the plunger, but after the dash pot and plunger have been cleaned all oil should be wiped off of same, as the oil would cause the plunger to collect dirt and stick.

51. Q. If one carbon of lamp should "jig or pound", what can be done to stop it?

A. If the carbon jumps or pounds the electrode, it is evident that the iron armature is too far out of the solenoid, or the speed is too low.

52. Q. Does the pounding of the lamp occur with the old series wound machines or with the new compound wound machines?

A. The pounding of the lamp occurs with the new compound wound machines.

53. Q. If the copper electrode was fusing, how would you know it?

A. By the fact, when copper is fused a shaft of green light will be thrown off instead of a shaft of white light.

54. Q. What should be done when a green light is seen?

A. Close the throttle to turbine engine, then open slowly until a white light re-appears.

55. Q. What is the cause of the copper electrode fusing?

A. The cause of the copper electrode fusing is due to too high speed of the generator, or having lead wires connected up wrong, allowing positive current to get into copper electrode first.

56. Q. What arrangements have been made so that you cannot connect your wires wrong?

A. The positive binding post both at the dynamo and lamp have been provided with a much larger hole to receive the wire than has been made in the negative binding post, and the ends of the positive wire should always be bent or doubled back so they will just enter the receptacle in the positive binding posts, but cannot be connected to the negative binding post.

57. Q. Should the copper electrode and holder become fused until no longer serviceable out on the road, what would you do?

A. Would remove the damaged holder from the lamp and subst.i.tute a carbon, securing the subst.i.tuted electrode in the bracket of lamp same as the electrode holder is held. Be sure that the end of the carbon comes up to center of reflector and does not rest on base of reflector or lamp.

58. Q. If you were running along with your light burning steady and nice, then suddenly the light began to flash badly and kept it up, where would you look for the trouble?

A. You would no doubt find one of the lead wires loose in binding post.

59. Q. If you were running along with light burning satisfactorily and suddenly your light went out, where would you be likely to find the trouble?

A. You would undoubtedly find carbon burned out, or a lead wire was broken off or out of the binding posts.

60. Q. If the light goes out while between stations, what course would an engineer pursue?

A. If investigation cannot be made within a few minutes thereafter to determine the cause, the steam should be shut off from the turbine engine until such time when cause of failure can be determined.

61. Q. Why is it essential to shut off steam and stop the equipment?

A. If failure was due to a short circuit, damage might be done to the armature or field coils by overheating.

62. Q. How does the equipment act when short circuited?

A. The engine will labor heavily and run slowly with a large volume of steam blowing at the exhaust, the carbon points and cab lights will only show a dull red light.

63. Q. How would you test for a broken circuit?

A. Would test for a broken circuit or open circuit: First, by placing a carbon across the binding posts at dynamo. If the trouble was in the dynamo, no flash would be seen, but if dynamo was all right you would get a flash; this would indicate that the trouble was on towards the lamp. Second: Go to the lamp, place your carbon across binding posts. If wire was broken between dynamo and lamp you would not get a flash. If your wires were all right you would get a flash and you would find your trouble in the lamp. No doubt, it would be a burned-out carbon.