ARMY TM 9-6115-641-24
AIR FORCE TO 35C2-3-456-12
4-10. ADJUSTMENTS AND TESTS.
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. Residua I 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)
Resistance
Component
MEP–802A
MEP-812A
Exciter Stator Leads
10.54 to 14.26 ohms
10.5 to 14.206 ohms
Exciter Rotor Leads
0.4926 to 0.6664 ohms
0.4889 to 0.6613 ohms
Generator Rotor Leads
2.46 to 3.33 ohms
1.553 to 2.101 ohms
Generator Stator Leads
0.3731 to 0.5047 ohms
0.1494 to 0.2022 ohms
Q, and Q2 Leads
0.9053 to 1.224 ohms
1.207 to 1.633 ohms
NOTE
Ambient temperature must be expressed in ‘C, To convert °C to °F use: °F = °C X 9 +
5+32
(1) To determine the resistance values at current ambient temperature, use the following formula:
RI = R25 [1 + 0.00385 (T-25)]
RI = 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):
RI = 12.4 [1 + 0.00385 (5-25]]
RI = 12.4 [1 + 0.00385 (-20)]
RI = 12.4 [1 + (–0.077)]
RI = 12.4 [0.923]
RI = 11.4 +/– 15% ohms
4-10-3. Testing Rotating Rectifiers. Two rectifier assemblies (Fl + and F2–) make up the rotating rectifier bridge assem-
bly (Figure 4–1 7). Set multimeter for ohms and test each CR using negative and positive polarities. Test rectifiers as fol-
lows:
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-802A) or paragraph 4–12–2 step h
(MEP-812A).
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.
4-21
