Electrical (Rev 1/97)
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d. Turn the commutator or the core down if they
exceed this limit. Also turn the commutator down
to remove any wear grooves made by the brushes.
e.
Replace the armature if the commutator has an out-
side diameter that is less than 1.142 in. (29.00 mm)
after being turned down.
f.
If the commutator is only dirty, clean it up with
500-600 grit sandpaper.
g. After turning down the commutator, check the
undercut of the mica. The standard undercut is .02-
.03 in. (0.5-0.8 mm). Cut the undercut down to the
proper depth if it is less than .02 in. (0.5 mm).
Check Undercut
h. Check the armature coils with a growler and an
ammeter. Place the ammeter leads on each pair of
commutator bars that are directly opposite each
other. The ammeter will show no current in an
open coil and lower than normal current in a
shorted coil. Replace the armature if any of the
coils are defective.
i.
Check the armature insulation with an ohmmeter
set on the RX1000 scale. There should be infinite
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resistance between each commutator bar and the
armature core or shafts. Replace the armature if
there is any continuity between the armature coils
and the core.
Check Armature Insulation
Gears and Bearings
Inspect the starter gear, idler gear, idler gear bearings, and
bearing retainer. Replace any of these parts that show signif-
icant wear or damage.
Inspect Gears and Bearings
Pinion Assembly
1. Inspect each part of the pinion assembly and replace
any part that shows significant wear or damage.
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