Table 5-1. DS and GS Troubleshooting (Contd)
Test or Inspection
Test the generator as follows:
General. On-equipment electrical test procedures may provide a basis for
determining the necessity and extent of generator repair. The resistance values and tolerances
contained in this paragraph should be used only as a general guide. Take into consideration the
test instrument used, test lead resistance, and the ambient temperature at the tune of the test If
more precise measurements are required, use an instrument such as a Kelvin Balance or a
Wheatstone Bridge and make comparative measurements between the suspected component
and like item that is known to be good.
(1) Disconnect the plug connector (P2) at the rear of the control box.
(2) Use a multimeter that has been set on the RX1 scale and test for continuity
between plug pins A and B, D and E, and C and F If continuity is not indicated (full deflection) on
any of the tests, remove the plug at the generator and repeat the tests at the generator. If again,
continuity is not shown, the stator is defective and must be replaced. Refer to para. 7-14.
(1) Remove the blower cover and fan (par 6-2 or 6-3).
(2) Use a multimeter that has been set on the RX1 scale and test between the rotor
field windings terminal and the case of the rotor. If the resistance is not within five percent above
or below the following values, the rotor must be removed for further testing (TM 5-764):
Model MEP 01 7A (60 Hertz)
Model MEP4-022A (400 Hertz)
Exciter Field Windings.
(1) Disconnect the plug connector (PI) at the rear of the control box.
(2) Use a multimeter that has been set on the RXI scale and test for continuity
between plug pins G and H. If the resistance is not within five percent above or below 54.4 ohms.
the windings are defective and must be replaced. Refer to para 7-14.
GENERATOR VOLTAGE TOO HIGH
Test the voltage regulator as follows:
Put output selector switch to desired output setting (fig. 2-4) and disconnect the load
Start the generator set (fig. 2-7 or fig. 2-8). Place the circuit breaker to the ON
position and check output selector switch to indicate load terminals were output voltage is applied.
Check set voltmeter for correct setting. Using a multimeter, check load terminals to
verify reading on set voltmeter. If voltage is low and the variable resistor on the control panel will
not correct the deficiency, check exciter voltage across terminals 20 and 21 of the voltage
regulator terminal board . This voltage will vary but should be about 30 volts. If voltage at
terminals 20 and 21 of the voltage regulator terminal board fails to meet specifications, the voltage
regulator is defective and should be replaced
Using a multimeter as a check against the set voltmeter, test the output terminals of
the generator set against all position settings of the voltage selector switch
Stop the generator set and connect the load cables.
Repeat steps 2 and 3 above. If the voltage regulator does not pass the test, replace
it. Refer to figure 7-3 for voltage regulator PN 13211E6975(97403) or
13212ES950(97403) or to figure 7-4 for voltage regulator PN 13219E0883(97403)
and to paragraph 7-6 for removal and installation. If the tests show the regulator is
not damaged, go on to step 2.
Change 10 5-3