Commutator Test: MPV
- Clean surface and polish with No. 400 sandpaper if required. If surface is scored, out of round or pitted, turn commutator in a lathe.
- Maximum commutator runout and minimum diameter of commutator must not exceed specification after turning.
- Standard commutator mica undercut depth is .020" (.50 mm). Minimum mica undercut depth is .008" (.20 mm). If not within specification, undercut to standard depth.