Armature Assembly
- Check the commutator for signs of seizure or stepped wear. If the symptom is minor, use sandpaper to repair. If it cannot be repaired, replace the armature assembly.
- Measure runout on the commutator.
Commutator runout:
Standard
0.05 mm (0.0020in)
Limit
0.10 mm (0.0039in)
- Measure the depth of the segment mold. If it is not within the specification, replace the armature assembly.
Depth of segment mold:
Standard
0.50 mm (0.020in)
- Place the armature assembly on the growler tester to check for short circuits. While slowly turning the armature assembly, support the steel sheet for the armature core. If the circuit of the armature is shorted, the steel sheet will vibrate, causing it to move towards the core. When the steel sheet has moved or vibrated, replace the armature.
- Check insulation between commutator segment and shaft. If there is continuity, replace the armature assembly.