Dc. Engine Collectors’ (commutator) roundness and smoothness:
A new or newly arranged collector should be av. 20 μm. round. This means vibration of Dc. engine collectors in μm. Prominent segments should not be larger than 1 μm. Higher frequencies outside the round must be of smaller motion amplitude. If a universal engine roundness exceeds 5 μm, it must not exceed 1/10 of the collector circumference. The average smoothness (Rz) of the collector should be 2-4 μm to ensure the best contact surface.
Dc. Engine Collectors’s operation:
Commutators may be turned or grinded. In order to obtain a good surface by using a diamond-tipped tool, the cutting surface must be thoroughly cleaned after the lower feed surface is turned.
-Cutting speed: 100-120 m / min
-Cutting depth :0,05-0,1 mm
-Feeding speed :30-50 µm/rev
Grinding the commutator in the opposite direction with a grinding stone by turning allows you to get better results. Grinding with hand does not work very well. This requires experience and should be considered in case of an emergency or if the machine can be stopped within a short time. Rubber polishing bar can be used to thin the thickness of the patina, but this can not eliminate burnt spots.