ARMY TM 9-6115-645-24
AIR FORCE TO 35C2-3-444-12
MARINE CORPS TM 09244A/09245A-24/2
e.
Tag and disconnect exciter rotor leads (3 places) from rotating rectifier by removing bolts (3, FIGURE 4-16) and
lockwashers (4).
NOTE
It will be necessary to bar (turn) the engine in order to position a specific area of the rotating
rectifier at one of the end bell access holes. Turn engine using center bolt on harmonic
balancer, refer to TM 9-2815-256-24.
f.
Connect resistance bridge, between two exciter rotor leads and note resistance reading. Continue this procedure
until readings are noted for each combination of leads (i.e., I and 2, 1 and 3, and 2 and 3).
g.
Resistance readings should be as shown in TABLE 4-3 for each combination of leads. Readings other than in
TABLE 4-3, indicate open or shorted windings and exciter rotor must be replaced.
h.
Set multimeter for ohms and connect between each exciter rotor lead and end bell in turn.
i.
Multimeter reading of less than infinity indicates defective ground insulation and exciter rotor must be replaced.
j.
Connect exciter rotor leads to rotating rectifier with lockwashers (4, FIGURE 4-16) and bolts (3). Remove tags.
TABLE 4-3. GENERATOR RESISTANCE VALUES AT 25°C (770F)
Resistance
Component.
MEP-806A.
MEP-816A
Exciter Stator.
Between 24.85 & 33.61 ohms.
Between 24.7301 & 33.4583 ohms
Exciter Rotor.
Between 0.202 & 0.274 ohms.
Between 0.2082 & 0.2816 ohms
Generator Rotor.
Between 0.52 & 0.70 ohms.
Between 1.0835 & 1.4659 ohms
Generator Stator.
Between 0.040 & 0.054 ohms.
Between 0.015 & 0.0202 ohms
NOTE
Ambient temperature must be expressed in O°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:
R1 = R25 [1 + 0.00385 (T-25)]
Where:
R1 = Unknown resistance
R25 = Known resistance at 250C (770F)
T = Current ambient temperature
(2)
Example for exciter stator leads at 50C (41 °F):
R1 = 29.23 [1 + 0.00385 (5-25)]
R1 = 29.23 [1 + 0.00385 (-20)]
R1 = 29.23 [1 + (-0.077)]
R1 = 29.23 [0.923]
R1 = 26.98 ± 15% ohms
k.
Install end bell cover plates, paragraph 4-19.2, step h.
I.
Install generator set housing rear panel, paragraph 2-18.4.
m. Connect negative battery cable and dose battery access door.
4-23.
GENERATOR ROTOR ASSEMBLY.
4-23.1 Testing.
a.
Shut down generator set. Allow generator to cool to ambient temperature.
b.
Open battery access door and disconnect negative battery cable.
c.
Remove generator set housing rear panel, paragraph 2-18.1.
Change 2 4-39
