1. INSPECT COMMUTATOR FOR DIRTY AND BURNT SURFACE
If the surface is dirty or burnt, correct with sandpaper (No.400) or on a lathe.
2. INSPECT COMMUTATOR FOR RUNOUT
(a) Place the commutator on V-blocks.
(b) Using a dial indicator, measure the circle runout.
Maximum circle runout: 0.05 mm (0.0020 in.)
If the circle runout is greater than maximum, correct it on a lathe.
3. INSPECT COMMUTATOR DIAMETER
Using vernier calipers, measure the diameter.
Standard diameter: 30.0 mm (1.181 in.)
Minimum diameter: 29.0 mm (1.142 in.)
If the diameter is less than minimum, replace the armature.
4. INSPECT UNDERCUT DEPTH
Check that the undercut depth is clean and free of foreign material. Smooth out the edge.
Standard undercut depth: 0.6 mm (0.024 in.)
Minimum undercut depth: 0.2 mm (0.008 in.)
If the undercut depth is less than minimum, correct it with a hacksaw blade.
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