4-16 ELECTRICAL
INSPECTION & SERVICING
Pinion
Inspect pinion.
Replace pinion if damaged or worn.
Armature and Commutator
Inspect the commutator surface.
If surface is gummy or dirty, clean with 400 grade emery paper
A.
Measure commutator outside diameter.
09900-20101 : Vernier calipers
Commutator outside diameter:
Standard
: 30 mm (1.18 in.)
Service limit : 29 mm (1.14 in.)
If measurement exceeds service limit, replace armature.
Check that mica (insulator) between the segments is undercut
to specified depth.
Commutator undercut:
Standard
: 0.5 – 0.8 mm (0.02 – 0.03 in.)
Service limit : 0.2 mm (0.01 in.)
If measurement exceeds service limit, cut to specified depth.
NOTE:
Remove all particles of mica and metal using compressed air.
Wear safety grasses when using compressed air.
A
SEGMENT
MICA
1. undercut
1