T O 35C2-3-442-2
between leads: T1-T4, T2-T5, T3-T6,
1. Disconnect diodes from the recti-
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.
the diode, meter positive lead on the anode
(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.
high resistance (several K ohms) should be
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
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
borne particles. Welding gog-
gles, with proper tinted lenses,
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 -
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
megger between leads and stator frame.
Check insulation resistance of main
400 hertz generators.
e. Repair or rebuild main rotor assembly as speci-
winding by electrically bonding rotor
together and connect a megger be-
for 400 hertz generators.
leads and rotor frame or rotor shaft.
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.
f. Repair or rebuild exciter rotor assembly as
specified in figure 7-6 for 50/60 hertz generators or fig-
r. Check insulation resistance of exciter
stator winding by electrically bonding statol
g. Repair or rebuild exciter stator assembly as
leads together and connecting a megger
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.