TM 9-4910-663-12
(2) Prior to starting any testing, this REVERSING switch must be
positioned for either NEG-GND or POS-GND, depending upon the generator
system being tested.
2-6. SPECIFIC MODES OF OPERATION. The following paragraphs contain
the instructions to operate the test stand in the various modes of
operation.
Figure 2-12 through 2-15 illustrate various typical test
setups.
2-7. TESTING INTERNAL GROUND FIELD AND EXTERNAL GROUND FIELD GENER-
ATORS. Either standard duty voltage regulators or heavy duty voltage
regulators may be used for control of automotive generators. The main
difference between the two systems is the method of generator field
control. In a standard duty voltage regulator, the generator field is
externally grounded, whereas in a heavy duty voltage regulator, the
generator field is internally grounded. When using FIELD CURRENT 0-30
AMPS (MAX) control (R26, fig 2-2) to control the voltage output of a
generator being tested without a voltage regulator, GENERATOR FIELD
switch (S37) must be set to either the EXT GND or the INT GND posi-
tion, as determined by the type of system undergoing test. When
testing a generator with a voltage regulator in the system, the regu-
lator itself will complete the field circuit.
NOTE
Attach leads from the generator to the test stand
in the same manner for either type of generator.
2-8.
TESTING VOLTAGE REGULATORS
CAUTION
Removal or installation of an electrical jumper or
connecting cable will be accomplished only when
that circuit is not being supplied with electrical
power unless specified in test.
Load resistors of 1/4 OHM, 1 1/2 OHMS, 2 1/4 OHMS, and 7 OHMS (below
S13, fig 2-2) are provided in the test stand for the fixed resistance
method of checking-and adjusting voltage regulators. The appropriate
fixed resistance is substituted for the external charging circuit.
Proceed as follows:
Disconnect the battery lead at the regulator.
a.
b. Connect a lead between the regulator BAT terminal and 1/4 OHM,
1 1/2 OHM, 2 1/4 OHM, or 7 OHM binding post (below S13, fig 2-2), as
applicable.
When REGULATOR CHECK FIXED RESISTANCE METHOD switch (S13,
fig 2-2) is set to the ON
position, the
selected fixed resistance is
connected between the regulator BAT terminal and the negative bus
circuit or ground. Normally, use the 1 1/2 ohm resistance with 12
2-31
Change 1