TM 5-683/NAVFAC MO-116/AFJMAN 32-1083
Figure 4-18. Example of eccentric commutator.
Figure 4-19. Dial gauge to measure commutator concentricity.
Figure 4-17. Good Commutator Films: a) A light, mottled
new oil while the motor is running since it is easy to
surface, b) Heavy film of nearly uniform color.
add too much. Check the oil while the motor is
stopped and, if required, add oil to the full level.
air line to blow out motor windings, first check to be
Excess oil is apt to leak into the motor and cause
sure that water has not condensed in the line.
damage such as:
d. Friction. Many motors fail because of excessive
(1) Deteriorate the mica-insulating segments
between commutator bars.
and is dragged along by rotation, forming a lubricat-
(2) Foul the commutator bars.
ing film that prevents friction. It is important to use
(3) Soak windings to the point where rewind-
ing may be the only way to prevent burnout break-
the right oil at the right time and not too much.
down of the motor.
Follow the manufacturer's instructions. Do not add