MD Helicopters 369-500, Maintenance Instructions Manual

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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96-10-00
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TR16-001
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.
14. Generator Control Unit Bench Test
(Ref. Figure 206) The following procedure is for
checking the circuits inside the 369D24284-3,
-5 Generator Control Unit. This should be
accomplished by knowledgeable personnel
only.
(1). Build a test box as described in
Figure 206 and install between a
variable power supply and the GCU.
(2). Field Flash: Verifies the field flash
circuit is working.
(a). Verify switch positions, SW1 and
SW2 closed, Gen Disable open.
(b). Increase voltage slowly to approxi­
mately 10 volts.
(c). Field lamp and Gen Out/Fail should
be dim and voltage at J and M should
be very low (a few millivolts)
(3). Line Contactor Control:
(a). Increase voltage to approximately 26
volts, field lamp and Gen Out/Fail
should brighten and differential
voltage between J and M should be
approximately 0.5 volts.
(b). Momentarily depress SW1 - Line
contactor lamp should be ON and
Gen. fail lamp should be OFF.
(c). Momentarily depress SW2 - Line
contactor lamp should be OFF and
Gen. fail lamp should be ON.
(d). Depress Gen Disable switch - Field
lamp should be OFF, Gen Out should
be ON.
(e). Release Gen Disable switch - Field
lamp should be ON and Gen Out/Fail
should be ON.
(4). Voltage Regulation: This is the propor­
tional band.
(a). Increase voltage until field lamp goes
OFF, this should be between 26 and
30 volts depending on voltage adjust
setting of GCU.
+
−
0 TO 32 VDC
VARIABLE
POWER
SUPPLY
15 AMP RATING
SW1
SW2
10A
GEN DISABLE
GEN OUT
FIELD
LINE
CONT.
A BUSS SENSE 4
3
2
1
CURRENT
LIMIT
GENERATOR CONTROL UNIT
369D24284-3, -5
B GENERATOR SENSE
F #2 CURRENT SENSE
D #1 CURRENT SENSE
K #3 CURRENT SENSE
R #4 CURRENT SENSE
J POWER IN
P GEN DISABLE
N
T
E
S GEN OUT LT.
M FIELD
H LINE CONTACTOR
G NEGATIVE SENSE
L PWR GND
G96-1018
Figure 206. GCU Bench Test