TM 5-3810-289-34
CHAPTER 3
REPAIR OF ENGINE AND ACCESSORIES
Section I. ENGINE ACCESSORIES
disassemble alternator to the extent necessary to
3-1. Alternator Assembly
perform the required maintenance.
a. General The alternator sustains the operating
d. Inspection and Repair. The frequency of
load requirements and at the same time recharges the
inspection is determined largely by the type of operating
batteries for subsequent engine starts. The alternator is
conditions. High-speed operation, high temperatures,
self-rectifying, using six rectifier diodes to convert the AC
and dust and dirt all increase the wear of brushes and
voltage to DC. Voltage regulation is provided by an
slip rings.
internally mounted voltage regulator assembly.
(1) Inspect terminals for corrosion and loose
Caution: Before performing work on the
connections.
alternator or associated circuitry several precautions
(2) Inspect wiring for frayed insulation.
should be observed to prevent damage to the
(3) Inspect mounting bolts for tightness.'
alternator.
(4) Inspect belt for proper alinement and
(1) When installing a battery, always make
tension. Inspect for excessive belt wear.
absolutely sure that the ground polarity of the battery and
(5) Inspect slip rings and brushes. These
ground polarity of alternator are the same.
can be inspected through the end frame assembly.
(2) When connecting a charger to battery,
Replace brushes if necessary. If slip rings are dirty,
connect charger positive lead to battery positive terminal
clean with fine sandpaper.
and charger negative lead to battery negative terminal.
Caution: Never clean slip rings with emery cloth.
(3) Never operate an alternator on open
Blow out with compressed air after sanding. If slip rings
circuit. Make absolutely certain all connections in the
are rough or out-of-round, alternator must be removed
circuit are secure.
and disassembled so slip rings can be trued in a lathe.
(4) Do not short across or ground any of the
The minimum diameter to which the slip rings can be
terminals on the alternator.
undercut is 0.015 of an inch on each side or a total of
(5) Do not attempt to polarize the alternator.
0.030 inch.
This procedure will almost certainly ruin the dicodes.
e. Reassembly. Reassemble alternator in reverse
b. Removal Refer to TM 5-3810-289-12 and
of disassemblv, c above.
remove the alternator.
c.
Disassembly.
Refer to figure 3-1 and
3-1
