MD Helicopters 369-500, Maintenance Instructions Manual

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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Page 214
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.
NOTE:
New brushes must be properly seated
on the commutator surface. Although the
brushes are of the instant-filming type,
they should be sanded and run-in for proper
seating before full load is applied to the
starter/generator. Failure to properly seat
the brushes can result in excessive sparking
that will cause burning and pitting of the
commutator.
(a). Place a strip of grade 5/0 or finer
sandpaper (CM801), slightly wider
than the combined width of the two
brush halves, around the commutator
with the sand side out.
(b). Cut the sandpaper strip to 1/8 inch
(3.175 mm) less than the commutator
circumference.
(c). Secure one end of the sandpaper strip
to the commutator surface with
masking tape so that the taped end
will lead in the direction of rotation,
and the other end will lead in the
direction of rotation, and the other
end will remain loose.
(d). Install the brushes in place against
the sandpaper and set the brush
springs in position.
(e). Carefully rotate the armature by
hand in the normal direction of
rotation until a full seat is obtained
on each brush. Do not sand excessive­
ly.
(f). Lift the brushes, and remove the
sand paper.
(g). Remove all carbon dust with dry,
compressed air, connect the brush
wire terminals, and proceed with the
brush run-in operation.
13. Start Relay
The start relay is a single-pole, single-throw,
normally open relay with enclosed contacts.
The relay connects battery or external power
to the starter when the START switch on the
pilot's collective pitch stick is pressed.
NOTE:
D
369D helicopters S/N 003 - 723 have re­
verse current relay mounted to oleo sup­
port fitting on right aft rib installation of
engine compartment.
D
369D helicopters S/N 724 and subs, 369E
helicopters S/N 001 thru 383 and 369FF
helicopters S/N 001 thru 075, the relay is
located on the left side of engine compart­
ment.
A. Installation of Transient Suppressor
(Start Relay)
To reduce the possibility of voltage spikes
damaging solid state circuits, it is recommend­
ed that a transient suppressor be installed on
the start relay on 369D helicopters S/N
003-539.
(1). Ensure all electrical power is OFF.
(2). Disconnect and remove start relay.
(3). Connect suppressor to terminals X1
and X2 on start relay.
(4). Reinstall start relay.
B. Start Relay Replacement
(Ref. Figure 203)
Consumable Materials
(Ref. Section 91 − 00 − 00)
Item Nomenclature
CM306 Lacquer, clear
(1). Ensure all electrical power is OFF.
(2). Disconnect and remove start relay.
(3). Check bonding surfaces for good
condition per Maintenance of Electrical
Bonding Connections. Position replace­
ment relay on mounting surface, secure
and connect wiring.
(4). Apply coating of lacquer (CM306) to
all-exposed electrical studs, terminals
and associated connecting hardware.