T O 35C2-3-442-2
P-8-627-34
TM 5-6115-457-34
TM-07464A-35
between leads: T1-T4, T2-T5, T3-T6,
1. Disconnect diodes from the recti-
T7-T10, T8-T11, and T9-T12. Resistance
fier assembly and test each diode separately
should be 0.00974 ohm for 50/60 hertz
using a suitable multimeter
generator sets and 0.00490 ohm for
400 hertz generator sets.
2. Connect the multimeter across
the diode, meter positive lead on the anode
1. Check main rotor resistance value
(back end of arrow) and negative meter lead
between leads R4 and R5. Resistance
on the cathode (tip of the arrow). A low
should be 0.834 ohm for 50/60 hertz
resistance should be indicated.
3. Reverse multimeter leads, a
generator sets.
high resistance (several K ohms) should be
indicated,
m. Check exciter rotor resistance
t. Inspect paint for damage.
values between leads R1-R2 and R1-R3.
7-6. REPAIR OR REBUILD.
Resistance should be 0.0772 ohms.
n. Check exciter stator resistance
value between leads F1 and F2. Resistance
Welding operations produce heat,
should be 1.23 ohms for 50/60 hertz gen-
h i g h l y toxic fumes, injurious
erator sets and 1.51 ohms for 400 hertz
radiation, metal slag and air-
generator sets.
borne particles. Welding gog-
gles, with proper tinted lenses,
NOTE
apron or jacket and welder's
boots are required.
Generator windings insulation
a. Repair cracks by welding as long as
resistance checks should be made
it does not distort or empair strength of
using a 500 volt megger. R e s i s -
part.
tance readings should be a mini-
b. Remove burrs or nicks using a
mum of 50K ohms.
suitable file or stone.
c. Straighten dented or distorted sheet
o. Check insulation resistance of main
metal parts using suitable tools.
stator windings by electrically bonding all
d. Repair or rebuild main stator
twelve leads together and connecting a
assembly as specified in figure 7-2 for
megger between leads and stator frame.
50/60 hertz generators or figure 7-3 for
p.
Check insulation resistance of main
400 hertz generators.
e. Repair or rebuild main rotor assembly as speci-
rotor
winding by electrically bonding rotor
fied in figure 7-4 for 50/60 hertz generators or figure 7-5
leads
together and connect a megger be-
for 400 hertz generators.
tween
leads and rotor frame or rotor shaft.
NOTE
Apply 6 to 12 VDC to rotor leads.
q. Check insulation resistance of exciter
Pass a compass around the diameter of
the rotor noting which pole of the
rotor winding by electrically bonding the
compass pointer is attracted to each of
three rotor leads together and connecting a
the wound poles. If the windings are
megger between leads and rotor frame or
correctly connected, all wound poles
will attract the same compass pole.
rotor shaft.
specified in figure 7-6 for 50/60 hertz generators or fig-
r. Check insulation resistance of exciter
ure 7-7 for 400 hertz generators.
stator winding by electrically bonding statol
leads together and connecting a megger
specified in figure 7-8 for 50/60 hertz generators or fig-
ure 7-9 for 400 hertz generators.
between leads and stator frame.
h. Remove damaged paint with a suitable scraper.
s. Inspect rectifier assembly as follows:
Blend in edges, prime, and paint damaged areas.
7-8
Change 9
