P-9-TM-457-35 T.O. 35 C2-3-442-2
TM-07464A-35 TM 5-611 5-457-34
CHAPTER 7
GENE RATOR ASSEMBLY REPAIR INSTRUCTIONS
WARNING
7-1. GENERAL.
The generator is a brushless type
Stay clear of generator
output leads.
with a rotating exciter. The armature of
the exciter, the field of the generator and
3. Remove electrical connector P61
the rectifier assembly are mounted on the
same rot sting shaft. The field of the ex-
from right side of generator endbell.
citer and armature of the generator are
4. Connect a variable dc voltage sup-
stationary. The output of the generator
ply (0-10 volt, 15 amperes) in series with
armature is kept at a predetermined con-
stant value by the generator set output. In
a 0-10 dc ammeter to connector J61 pin C
order to build up the voltage of a generator,
(positive) and pin B (negative). Set variable
the residual magnetism of its pole pieces is
voltage supply to zero.
generally relied upon to produce a small
5. Start generator set and operate
initial voltage which increases as the gen-
erator comes up to speed. If this is not
engine at rated speed, 1800 RPM, for
sufficient, the exciter regulator flashes the
50/60 hertz generator sets or 2000 RPM
field. This voltage is fed from the exciter
for 400 hertz generator sets.
armature to the bridge rectifier assembly,
the dc output of which is coupled to the gen-
6. Adjust variable voltage supply
until normal generator output voltage is
erator field rotating on the same shaft with
obtained (120/208 or 240/416). Test dc
the exciter armature and rectifier assem-
ammeter should indicate 3 to 3.5 amperes
bly. The generator field induces an ac
for 50/60 hertz generator sets and 6.25 to
voltage in the stationary armature windings.
6.75 amperes for 400 hertz generator sets.
7-2. ON EQUIPMENT TEST.
7. Remove external power supply
and shut down generator set.
a. Symptom and Isolation of Malfunc-
tion. A malfunction of the generator is
8. If above requirements are met,
usually indicated by either low output
refer to paragraph 6-76 and test the exciter
voltage or no voltage output. To isolate the
regulator. If requirements are not met,
malfunction proceed as follows:
proceed as indicated below.
1. Disconnect generator set air
intake doors, below control cubicle, by re-
NOTE
moving fourteen screws, washers, and nuts.
2. Disconnect generator set air inlet
Generator temperature should
louver and screen assembly, by removing
be approximately 77 F during
twenty screws, forty washers and sixteen
resistance test.
nuts.
Change 7 7-1
