A. The copper electrode should have about one-eighth inch surface on the
contact point.

16. Q. How far should the copper electrode project over the holder?

A. About one inch.

17. Q. Should the electrode be raised up to one and one-half 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.

18. Q. What regulation should be given to the tension spring No. 93 of
the lamp, and why?

A. This tension spring, No. 93, should be regulated when the current is
off the lamp and should be adjusted only tight enough to pull the magnet
yoke up against the top stop lug on the side of lamp column.

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?