Check for shorted field by measuring between
generator. This procedure is important to pre-
terminal lugs with low-range ohmmeter. Re-
vent damage to system after generator builds
sistance should be approximately one ohm.
up voltage. To test generator, connect 0-5
Check for grounded field can only be made
ampere ammeter in series with lead to FLD
with field coils installed, but grounded field
terminal of generator and 0-50 a m pe r e
indicates breakdown of coil insulation which
ammeter in series with lead to ARM terminal,
may be visible on close inspection. Check for
Connect 0-50 volt voltmeter from FLD termi-
open armature coil by inspecting commutator
n a l to generator frame and 0-50 v 01 t
bars for burned areas. Bar to which open coil
voltmeter from ARM terminal to genera-
t o r frame, Connect low-resistance high-
should be connected will be burned by arc
each time it passes under brush. Check for
wattage variable resistance from ARM ter-
short circuit in armature with growler and
minal to frame through heavy-duty knife
thin strip of steel such as hacksaw blade.
switch. Disconnect generator from voltage reg-
Place armature in growler and rotate slowly
ulator. Rotate generator at speed sufficient to
while holding steel strip over top. Steel strip
build up voltage at FLD terminal to exactly
will vibrate above area of armature core in
24 volts. At this point ammeter should indi-
which shorted armature coils are located. If
cate between 0.94 and 1.02 amperes at room
short is visible at ends of core laminations
temperature. Change speed if necessary to
it may be possible to repair it. Check for
1900 rpm and close knife switch. Adjust re-
grounded commutator coil with test lamp.
sistor for current of 18.0 amperes in ARM
Place one test point on shaft and other test
lead. Voltmeter from ARM terminal to frame
point on end of each commutator segment in
should indicate 25.8 to 26.2 volts.
turn. Do not touch face of commutator bars
with test point. Lamp should not light at any
test point. Inspect commutator for roughness,
(Model LEB 300)
high mica, and out-of-round condition. If very
graph 3-34 to remove and install the starter
slightly rough, commutator can be recondi-
motor and solenoid.
tioned with No. 00 sandpaper. For correction
b. Disassembly.
of other conditions, turn commutator down in
(1) Disconnect leads to solenoid and re-
lathe until commutator is smooth and concen-
move solenoid (17, fig. 6-4) from starter by
tric with shaft, then undercut mica to depth
removing screws (35) and lockwasher (27).
(2) Remove cover (10, fig. 6-5) by re-
No. 00 sandpaper. Check bearings (24 and 31).
moving attaching hardware, then remove in-
e. Repair. Replace brushes if worn more
sulator (9), spring (7), contact (8) and con-
tact and push rod (6) from housing (1),
(25) or field coil (38) which are defective and
(3) Remove frame (1, fig. 6-4) by re-
cannot be easily repaired. Turn down com-
moving thru bolts (37), then remove housing
mutator in lathe if rough or out-of-round and
(16) .
Replace all other parts which do not pass in-
( 4 ) Remove spring (18) and plunger
spection.
(19 ) from shift lever (20). Remove shift lever
f. Reassembly. To reassemble, reverse the
(20) from housing (16) by removing stud
disassembly procedure.
(22), washer (26) and nut (29).
g. Adjustment.
After
battery-charging
(5) Remove armature (10) from housing
generator has been reassembled, polarize gen-
(38), then remove collars (13 and 15), ring
erator to insure correct polarity of output,
(14), drive assembly (12) and spring (11).
Connect generator on test stand to voltage reg-
(6) Remove pole shoes (44) by removing
ulator and battery with which generator is to
screws (34), then remove field coil (8) and
be used. Before rotating generator, connect
shunt coil (9).
jumper lead momentarily between GEN and
(7) Remove brush holders (3 and 4),
BAT terminals of voltage regulator. Momen-
spring (5), support (6) and lead (7).
tary surge of current will correctly polarize
c. Cleaning. Clean studs, nuts and metal
