TM 5-4930-207-34
(3) Check brush holders for shorts to ground
b. Cleaning.
with a test light.
(1) Use a cloth dampened with P-D-680 to
wipe all dust, oil, and foreign material from the
f. Armature End Play Test.
brush plates, end frames, armature, and field
-
(1)
Align
end
of
armature
shaft
with
assemblies.
plunger of dial indicator. Pull shaft to outer limit
(2) Use filtered compressed air to blow dust
and set dial indicator.
and dirt from crevices of the armature and field
(2) Push shaft in toward commutator end
windings.
o f generator to its inner limit. Dial indicator
(3) Secure armature in a lathe, With arma-
should read between 0.003 and 0.010 inch.
ture spinning, hold an emery cloth against the
(3) If dial indicator reading is not within
commutator until the copper is bright and smooth.
these limits, improper assembly or worn parts are
c. Inspection.
possible causes. Check bearings to be sure of
(1) Examine field coils for worn or burned
proper seating.
insulation. Be certain connections between field
g. Reassembly and Installation.
coils are secure. Repair connections if necessary.
(1) Reassembly is the reverse of disassem-
(2) Examine field frame assembly for cracks
bly. Refer to figure 3-1.
or distortions. Check thread conditions in tapped
holes.
(2) Install the generator assembly and volt-
( 3 ) Check drive end head for cracks or
age regulator as instructed in TM 5-4930-207-12.
warping, Inspect shaft end of armature for dam-
h. Field Current Draw Test.
age and wear.
(1) Connect the generator in series with a
(4) Examine pulley for broken flanges and
battery, battery switch, variable resistor, and
worn shaft hole. Inspect brushes for wear or
damage.
ture and field connections.
d. Repair.
(2) Before closing battery switch, connect
(1) Check commutator with a dial indicator
a m m e t e r to its highest range. Close battery
for out-of-round. If total out-of-round exceeds
switch and read ammeter. Open battery switch
0.001 inch, turn down commutator on lathe.
and connect ammeter to lowest range which will
(2) Replace armature or coils if tests indi-
safely carry current indicated in first reading.
cate shorts.
(3) Close battery switch. Adjust variable
(3) Replace all parts indicating cracks, wear,
resistance to produce a reading of 5 volts on the
or damage.
voltmeter. The ammeter should indicate 1.00 to
(4) Replace brush springs that are worn or
1.05 amperes.
fatigued. Replace brushes.
(5) Undercut mica insulation between the
i. Polarizing Generator.
commutator bars to a depth of 1/32 of an inch.
(1) Polarize generator before starting engine
When undercutting mica, the cut should be square
whenever generator cable has been removed from
and free of burrs.
generator.
e. Testing.
(2) Disconnect generator-to-voltage regu-
(1) Use a conventional test light and check
lator cable, and battery connection cable from
field coils for open circuits and shorts to ground
voltage regulator; momentarily connect a wire
or between coils.
from the "B" terminal of generator cable to bat-
(2) Check armature assembly for open coils
tery connection cable.
and shorts to ground, or between coils by using
(3) Install cable.
a test light.
Section Il. STARTER ASSEMBLY
mounted to the flange on the starting motor drive
3-3. General
housing operates the overrunning clutch drive by
The shift lever cranking motor has the shift lever
means of a linkage and shift lever. When the con-
mechanism and the solenoid plunger enclosed in
trol switch closes the cranking circuit the soIenoid
the drive housing protecting them from exposure
is energized, shifting the starting motor pinion
to dirt and icing conditions. A solenoid switch
into mesh with the engine flywheel ring gear and
3-2
