ARMY TM 9-6115-642-24
AIR FORCE TO 35C2-3-455-12
MARINE CORPS TM 09247A/09248A-24/2
4-10.1 General. All of the following adjustments and tests can be performed without disassembly of the generator.
They should be used for testing generator and regulator components to ensure proper operation.
4-10.2 Residual Magnetism. Residual magnetism is automatically maintained in the generator exciter field poles by
the generator set electrical control system. Therefore, there will be no requirement to restore the residual magnetism.
TABLE 4-1. GENERATOR RESISTANCE VALUES AT 25°C (77°F)
NOTE
Ambient temperature must be expressed in °C. To convert °C to OF use: °F= °C x 9 / 5
+32
(1) To determine the resistance values at current ambient temperature, use the following formula:
R1 =
R25 [1 + 0.00365 (T-25)]
R1 =
Unknown resistance
R25 =
Known resistance at 25°C (77°F)
T =
Current ambient temperature
(2) Example for exciter stator leads at 5°C (41°F):
R1 = 12.4 [1 + 0.00385 (5-25)]
R1 = 12.4 [1 + 0.00385 (-20)]
R1 = 12.4 [1 + (-0.077)]
R1 = 12.4 [0.923]
R1 = 11.4 ± 15% ohms
4-10.3 Testing Rotating Rectifiers Two rectifier assemblies (F1+ and F2-) make up the rotating rectifier bridge assembly
(FIGURE 4-17). Set multimeter for ohms and test each CR using negative and positive polarities. Test rectifiers as follows:
a.
Shut down generator set. Allow generator to cool to ambient temperature
b. Open left side engine access door and disconnect negative battery cable.
c.
Open storage box access door and output terminal board access door.
d. Remove end bell cover from generator, paragraph 4-11.1, step e (MEP-803A) or paragraph 4-12.2 step h
(MEP-813A).
NOTE
The following steps will require turning the generator by hand. Use engine fan to turn
engine and generator.
e.
Tag and disconnect four leads from F1+ assembly.
f.
Connect positive lead of multimeter to F1+ stud and negative lead to CR1. Record resistance value.
g.
Connect negative lead of multimeter to F1+ stud and positive lead to CR1. Record resistance value.
4-19
4-10 ADJUSTMENTS AND TESTS.
