MD Helicopters 369-500, Maintenance Instructions Manual

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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TR16-001
96-10-00
The information disclosed herein is proprietary to MD Helicopters, Inc.
Neither this document nor any part hereof may be reproduced or transferred to
other documents or used or disclosed to others for manufacturing or any other
purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright
©
1999 − 2016 by MD Helicopters, Inc.
7. Generator
The generator, part of the combined, self-
cooled starter/generator assembly, normally
provides primary 28 Vdc power for operation of
the complete electrical system during engine
operation. Maximum intermittent duty rating
for the generator is 30 volts dc, 150 amperes
within the speed range of 7200 - 13,000 rpm.
A shear point is incorporated in the generator
drive shaft mechanism to protect the engine
drive from excessive torque loads. Generator
operation is controlled by the GEN-OFF
switch on the instrument panel. Maintain the
generator per starter/generator instructions.
For flashing the generator field refer to
Flashing of Generator Field.
NOTE:
369FF - 600N helicopters have genera­
tors rated at 200 amperes within the speed
range of 7050 - 12,000 rpm.
A. Generator Field Flashing
Flashing the generator field is required when
the starter/generator fails to produce adequate
output voltage due to loss of residual mag­
netism or reversed field polarity. (Failure is
indicated by zero or negative ammeter reading
and an illuminated GEN-OUT caution light.)
Do not flash field while starter/
generator is in operation as
damage to voltage regulator may result.
(1). Disconnect wires from generator field
stud A+ and stud D (Ref. Figure 204).
(2). Connect one end of jumper wire to
generator field stud A+.
(3). Connect other end of jumper wire to
BAT terminal of reverse current relay
(Ref. Figure 203).
(4). Ensure GEN-OFF switch is OFF and
place master switch at BAT; not
exceeding a total contact of more than 5
seconds.
(5). Place master switch at OFF.
(6). Disconnect jumper wires and reconnect
field wire to terminal stud A+ and wire
to terminal stud D.
(7). Operate engine for generator check. If
flashing field fails to correct generator
polarity, check for incorrect connections
or defective field circuit.
8. Engine Starting Equipment
Engine starting equipment consists of a
starter/generator, start relay and a start
switch on the pilot's collective pitch stick.
When pressed, the START switch energizes
the solenoid of the start relay which closes and
applies dc power from the dc main power bus,
thru the BAT
terminal of the reverse current
relay to the start winding of the starter/gener­
ator. Simultaneously, while the START switch
is pressed, the voltage regulator opens the
generator field circuit, the starter/generator
operates as a series motor and the ignition
circuit is activated.
9. Starter/Generator
(Ref. Figure 204) The starter/generator is a
combined, self-cooled unit. The unit is clamp
attached to a quick-disconnect mounting on
the engine power and accessory gearbox. The
starter/generator both starts the engine and
generates dc electrical power. Starter opera­
tion is controlled by the START switch located
on the pilot's collective pitch stick. A terminal
block on the starter/generator provides for
connection of electrical wiring and contains a
radio frequency-interference (RFI) filter.
Access to brushes in the starter/generator is
through a brush cover that is rotatable in
increments of 90 degrees.
NOTE:
Starter limitations for engine compres­
sor cleaning are provided in the appropriate
Pilot's Flight Manual.
10. Starter/Generator Replacement
(Ref. Figure 204)
A. Starter/Generator Removal
(1). Ensure all electrical power is OFF.
(2). Tag and identify electrical wiring and
disconnect from starter/generator
terminal block; insulate wiring termi­
nals.
(3). Remove starter/generator.
(4). Remove mounting flange with gasket.
(5). Install suitable protective closure over
opening in mounting flange.
CAUTION