Section II. MOTOR-GENERATOR
all varnish off the pole piece and off the internal dovetail
of the magnet frame.
The motor-generator is an electric alternating current
96. Cleaning, Inspection, and Repair
unit with a direct current output. The unit is rated at a
nominal 300 amperes at a 60 percent duty cycle. The
a. Clean all parts in an approved cleaning solvent
motor-generator set should be placed on a sturdy bench,
and dry thoroughly. Loose dirt can be removed from the
at a convenient height for disassembly, and located so a
windings with compressed air or vacuum. Oil or grease
suitable lifting device can be operated over the unit.
mixed with dirt can be dissolved with an approved
Vertical assembly is recommended for the convenience
cleaning solvent and then blown out. After cleaning, dry
it provides, and minimizes the danger of bearing
by heating at 900 to 1000 C. for 2 hours.
b. The commutator should be cleaned and, if worn in
grooves, it should be turned down smooth, and the mica
c. Inspect brushes and brush holders. Inspect
b. Remove attaching hardware and remove motor-
bearings for wear and general condition. Inspect studs
generator from truck frame.
and terminals for burned or otherwise damaged threads.
Repair or replace defective parts as necessary.
Disassemble the motor-generator
Reassemble the motor-generator in reverse order of
Note. The rubber air seals between the fan housing
and the magnet frame must be placed when
Note. An arbor press should be used when replacing
reassembling to assure proper air flow. The reactor air
bearings. Always press on the inner race. Always
baffle must be replaced to provide proper cooling of the
replace rubber bearing girdle when replacing bearings.
When replacing brush holders, make certain the
Remove the armature and fan assembly as a unit,
insulated bushings are in their correct location. Reseat
taking special care to avoid damaging the commutator
all brushes after assembly.
end bearing. If bearings need replacing a bearing puller
that presses against the inner race should be used. If it
is necessary to remove a bearing by pulling on the outer
race, it is imperative that a new bearing be replaced. If
a. Install motor-generator on truck with attaching
it is necessary to replace a coil, preheating the magnet
frame to 1500 F. maximum, will help to loosen the
varnish and make disassembly easier. The coil and
Re-check all wiring before starting welding
pole piece assembly can be pushed directly out of the
magnet frame. It will be necessary, before reassembly,