18-6
• MICA DEPTH
Measure the mica depth. If the grooves are clogged or mica
depth is less than the service limit, recut the grooves using a
hacksaw blade or a small file.
• COMMUTATOR
1) Measure the commutator O.D. If the measurement is less
than the service limit, replace the armature with a new one.
2) Measure the commutator runout using a dial gauge.
If the measurement is more than the service limit, replace
the armature with a new one.
3) Check the commutator (insulaor) for damage, dust, dirt and
metal particles.
If there is stain, irregularity and/or evidence of burning,
clean with an emery paper #500 or #600.
STANDARD
SERVICE LIMIT
0.4 – 0.5 mm
0.2 mm
(0.016 – 0.020 in)
(0.008 in)
STANDARD
0.1 mm (0.004 in)
STANDARD
SERVICE LIMIT
29.4 mm (1.16 in)
28.8 mm (1.13 in)
