TM 5-3820-233-35/2
CHAPTER 3
ENGINE REPAIR INSTRUCTIONS
Section I. ENGINE ACCESSORIES
29. General
This section contains those items which are considered
accessories to the engine. They consist of the starter,
battery-charging generator, radiator, water pump,
hydraulic governor, fuel pump, blower, blower drive, and
overspeed governor.
30. Starter
a.
General. The starter is a 24 volt, 4-brush,
gear drive type. The starter converts the electrical
energy, of the batteries into the mechanical energy
necessary to crank the engine. The tarter incorporates
an overrunning cloth which shifts the starting motor
pinion into mesh with the flywheel ring gear.
b.
Removal. Refer to Operator's manual.
c.
Bench Testing
Note
Never operate the cranking motor
more than 31 seconds at a time
MIN.
MAX.
MIN.
R.P.M.
without pausing to allow it to cool at
VOLTS AMPS
AMPS
R.P.M.
MAX.
least two minutes.
23.0
60*
90*
7000
10700
*INCLUDES SOLENOID
(1)
The armature should be checked for
freedom of operation by turning the
Figure 10-1. No load test.
drive. Tight, dirty, or worn bearings,
bent armature shaft, or loose pole
(b) Rated current draw and no-load
shoe screw will cause the armature to
speed indicates normal condition of the cranking motor.
drag and it will not turn freely.
(c)
Low free speed and high current
(2)
No-Load Test (fig. 10-1)
draw indicates: tight, dirty, or worn bearings, bent
armature shaft or loose pole shoes allowing armature to
(a) Connect the cranking motor in
drag, shorted armature, grounded armature or fields.
series with a fully charged battery to provide 24 volts, an
(d) Failure to operate with high
ammeter capable of reading several hundred amperes,
current draw indicates a direct ground in the terminal or
and a variable resistance. Also connect a voltmeter as
fields.
illustrated, from the motor terminal to the motor frame.
(e) Failure to operate with no
An rim indicator is necessary to measure armature
current draw indicates an open field circuit, broken brush
speed. Proper voltage can be obtained by varying the
springs, worn brushes, high insulation be-
resistance unit.
3-1
