19.  Q. If this tension spring was tightened too tightly, what might happen?

A. At usual speed between stations, the movement of the engine would impart an added resistance against the pull of the solenoid by the tension spring, which would shorten up the arc and dim down the light.

20.  Q. Is there anything else that could cause the light to dim down when the engine is running fast?

A. Yes; if the spring No. 92-A that hold the heel of the clutch should be too weak, the heel of the clutch would be forced up by the motion of the locomotive; this would release the carbon which would fall to the point of the copper electrode, causing the light to dim down, or, if the clutch should be used until the sharp edge that grips the carbon should have become worn smooth or round, the same would occur.

21.  Q. If the light burns satisfactorily while the engine is in motion, but goes out when engine is stopped, where would you find the trouble?

A. This trouble is most always found to be caused by the tension spring No. 93 being too weak, though if the dash-pot plunger has become corroded until it sticks in the dash-pot, the light will act the same as if the tension spring were too weak.

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

A. Coal oil could 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 must be wiped off, for oil would cause the plunger to stick as well as collect dirt.

23.  Q. If the carbon of lamp should “jig or pound”, what can be done to stop it?

A. If the carbons pound the electrode, it is evidence that the iron armature No. 64 may be too far out of the solenoid, or the speed of the turbine engine may be too slow.  This trouble can be remedied by adding another link to the suspension link, which has one end connected to the magnet yoke, the other end being connected to the iron armature No. 64.  If, however, when the arc is formed, it is found that the bottom end of iron armature No. 64 measures one-half inch from bottom of solenoid, the pounding is caused by the speed of turbine engine being too slow.

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

A. When the copper electrode is fused, a green light is always given off.

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

A. Immediately close off on the steam throttle until a white light re-appears.

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

A. Usually too high speed of the armature, although should you connect the wires up wrong that the current flowing from the dynamo to the lamp should enter the lamp at the electrode instead of passing through the carbon first, you would get a green light and fuse the electrode.

27.  Q. What arrangements have been made so that you cannot connect the wires wrong?