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Commutator Test

  1. Using "V" blocks and dial indicator, check commutator runout (out-of-round). See STARTER SPECIFICATIONS  . Turn commutator/armature on lathe until runout (out-of-round) is within specification.
  2. Check commutator diameter. If commutator is less than specification, replace armature. See STARTER SPECIFICATIONS  .
  3. Ensure continuity exists between any 2 commutator segments. If continuity does not exist, replace armature.
  4. Clean commutator segment surfaces with emery cloth and polish with No. 400 grit sandpaper (if necessary). If surface is scored, out-of-round, or pitted, turn commutator/armature assembly on a lathe.
  5. Measure undercut depth of insulating mica. Refer to the STARTER SPECIFICATIONS  . If mica depth is not within specification, undercut to specified depth using hacksaw or replace armature.