TM 10-3950-206-12
(a) Conditions: Ignition switch on, engine
required refer to direct support maintenance.
running.
(2) Clean all other parts in an approved
(b) This is a test of the alternator capability
cleaning solvent and inspect for damage. Replace any
to produce maximum current. A carbon pile load is
defective parts found.
e. Installation.
applied to the battery to induce maximum charging
current (fig. 4-8F).
(1) Install the alternator by reversing
(c) Place ammeter on 0-100 amp scale.
instructions for removal.
Unload carbon pile when connecting to battery posts.
(2) Adjust fan belt tension, by pulling out on
Start engine, set at fast idle. Apply partial carbon pile
alternator and securing with adjusting strap (2) at a point
load, or vehicle accessory load, to produce a 20 ampere
that will provide approximately 3/4 inch deflection in the
charge for a few minutes to warm up components.
belt, midway between the crankshaft and fan pulleys.
(d) Adjust engine speed to provide 3000 to
4-22. Voltage Regulator
4000 alternator R.P.M. Increase carbon pile load, note
a. The voltage regulator is an electrical switch- ing
maximum current produced with, volt- meter between
device sealed at the factory, requiring no adjustments. It
13.0-15.0 volts.
senses the voltage appearing at the regulator terminal of
(e) The minimum acceptable output
the alternator and supplies the necessary field current for
current is 43.0 to 46.0 amperes. Output voltage must
maintaining the system voltage at the output terminal.
remain between 13.0 and 15.0 volts.
b. Testing of the voltage regulator is accomplished
(f) Unload carbon pile immediately after
in the on-equipment testing of the alternator, paragraph
test to avoid battery discharge. If the alternator cannot
4-21, b.
produce its minimum rated output it should be
4-23. Starting Motor
disassembled for inspection and repair, refer to Direct
a. General. The starting motor is a self-contained,
Support Maintenance.
electromechanical unit, mounted on the engine flywheel
(g) System voltage drop is tested with the
housing, and engaging the fly- wheel ring gear during
alternator producing 10 amperes.
The maximum
starting periods. Organizational maintenance is limited
allowable voltage drop between the alternator and the
to starter and
I solenoid on equipment test and
battery is 0.3 (three tenths) volts.
replacement.
(h) Voltage loss above allowable
b. On Vehicle Testing. Before removal of starter,
maximum may require cleaning and tightening
inspect and test a faulty starter system as follows:
connections or use of heavier gauge output cables.
(1) Inspect all wiring and terminals for
c. Removal
looseness and corrosion. Check for worn or frayed
(1) Disconnect the positive battery cable from
insulation which could result in short circuits (grounding).
the battery.
Clean and tighten all connections.
(2) Tag and disconnect all electrical leads from
(2) Check batteries (para 3-10). Replace
alternator.
batteries which indicate one or more defective cells.
(3) Loosen screw assembled washer (5, fig. 4-
(3) Attach one end of a jumper cable to the
solenoid motor terminal. Momentarily make con- tact
(4) Remove screw assembled washer (5),
with other end of jumper cable on solenoid battery
washer (4), nut (7), spacer (10), washer (12), capscrew
terminal. If starting motor operates, the solenoid is
(14), and lift alternator (11) from mounting bracket.
defective and must be replaced. If starting motor does
(5) Remove screw assembled washer (1),
not operate, replace starting motor.
adjusting strap (2), and spacer (3).
c. Removal.
(6) Remove two nuts (6) and bracket (15).
Note. Disconnect the positive battery cable
Remove studs (16) only if replacement is required.
from- the battery.
d. Cleaning, Inspection, and repair.
(1) Disconnect leads to starting motor
(1) Clean the exterior of the alternator
solenoid.
assembly with a damp cloth and dry. Inspect alternator
(2) Remove the two screw assembled washers
for cracked housing, excessive end play of shaft or other
(8, fig. 4-9) and slide the nose of the starter drive
signs of damage. If damaged in any way or "on
housing from the flywheel housing.
equipment testing", (para b, above) indicates repair
4-16
