TM 9-2320-211-20
(4) Connect one end of the negative voltmeter
a. Prior to starting engine, check the generator
f a n belts for proper adjustment. Generator belts
lead to the negative terminal of the tester (fig. 2-8).
must be adjusted in accordance with paragraph 2-
and the other end to the same negative (--) ter-
minal of the battery to which the negative ammeter
lead is connected.
L o o s e belts can give low voltage readings, low
(5) Turn the voltage selector switch to the 20-
amperage readings, and can cause belt squeal.
volt scale.
b. Turn the ignition switch to ON, and observe
(6) Turn on load bank switch and install a
the battery generator indicator (fig. 2-14); the
load of 80 to 90 amperes by turning the load bank
indicator pointer should be on the yellow scale or on
the edge of the green scale. The indicator pointer
knob clockwise. Read the voltmeter.
should never be on the red scale when the ignition
(7) Battery voltage under load should not
switch is in the ON position.
drop below nine volts.
( 8 ) Turn
the load
bank
knob
coun-
terclockwise to the stop position. Turn off the load
selector
the
switch.
and
switch
Disconnect
all leads from the battery and then
disconnect all leads from the tester.
d. Combined Battery Voltage Check. To c h e c k
c o m b i n e d voltage, c o n n e c t the voltmeter in ac-
cordance with figure 2-13. and take the readings
shown.
CAUTION
D o not c r a n k o v e r 3 0 s e c o n d s . B a t t e r y
voltage must not be less than 18 volts to
properly fire ignition.
( 1 ) Open circuit voltage should be 24 to 26
volts.
(2) Leave the ignition off. Leave the test lead
on. Crank the engine with the vechicle starter.
( 3 ) If the batteries will not meet the above
criteria, replace or charge the batteries.
c. Start the engine and observe the action of the
battery indicator. When the engine is operated at
a p p r o x i m a t e l y 1000 to 1200 rpm, the meter in-
dicator pointer should move toward the green scale
or to the right side of the meter (fig. 2-14).
d. lf the meter does not operate as prescribed,
NOTE
the following troubleshooting procedure should be
Troubleshooting of the generating system
taken.
includes checking of the generator,
( 1 ) Turn the ignition switch to OFF.
(2) Disconnect the wire at the battery in-
generator circuit, four components on t h e
d i c a t o r and connect it to the positive lead of a
vehicle must be checked in the following
voltmeter (fig. 2-15). With the negative lead of the
sequence to insure trouble-free operation
voltmeter grounded, and the ignition switch ON,
and a minimum of meter connections.
the voltmeter should indicate battery voltage.
