MD Helicopters 369-500, Инструкция по техническому обслуживанию

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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[ Chapter 95 TOC ]
95-00-00
Page 7
Revision 7
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Neither this document nor any part hereof may be reproduced or transferred to
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purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright
©
1999 − 2016 by MD Helicopters, Inc.
completed from the external ground
through the associated external caution
lamps and PANEL LT circuit breaker
CB104 to the +28 Vdc source. A diode
(CRll or other diode, as applicable) is
provided for each individual negative
input fault circuit for use in press-to-
test circuits (Ref. Caution and Warning
Lights Press-to-Test Circuits).
(2). Negative (Ground) Input Fault Warn­
ing Light Indicator Circuits:
Negative input fault warning light
indicator circuits for the XMSN high
OIL TEMP and/or low OIL PRESS
lamps function when a ground is
applied from the associated sensor
switch to the dimmer assembly. When
ground is applied, a current path is
completed through external warning
indicator lamps to the transmission oil
and temperature light circuit. Dc
voltage is applied to the warning
indicator lamps. A diode CR9 (or CRl0)
is provided for each of the two negative
input fault circuits for use in the
press-to-test circuits (Ref. Caution and
Warning Lights Press-to-Test Cir­
cuits).
(3). Positive (+28 Vdc) Input START PUMP
Caution Light Circuit:
The START PUMP caution light circuit
functions when an ex28 Vdc
input is applied through diode CR8 to
the external START PUMP caution
lamp. The input is applied when the
start pump is energized by the START
PUMP circuit breaker CBll8 on the
instrument panel. Diode CR4 is
provided for use in the press-to-test
circuits (Ref. Caution and Warning
Lights Press-to-Test Circuits).
(4). Engine Out (ENG OUT) Warning Light
and Horn Circuit:
The ENG OUT warning light and
audible horn functions when the engine
out frequency sensor circuit in the
Autronics Engine Power Out (EPO)
Warning Control Unit is activated by a
decrease of engine speed to a specific
value of N
1
rpm (Ref. Engine Out (N
1
)
Frequency Sensor Circuits, Sec. 95-30).
When this occurs, a pulsating dc
voltage input from the sensor circuit is
applied through diode CR7 and flashes
the ENG OUT lamps. Simultaneously,
the pulsating dc voltage is applied to
and activates the audible warning horn
DS105 by means of the circuit through
part of the closed generator (GEN)
switch S4. When open, GEN switch S4
disables the audible warning horn.
Diode CR3 is used in the press-to-test
circuits.
NOTE:
On 369E helicopters S/N 384 and subs,
and 369FF helicopters S/N 076 and subs,
the generator switch does not enable the en­
gine out warning and audible headset warn­
ing. The horn and audible warnings func­
tion only when the helicopter is airborne
and an engine out condition is sensed by the
EPO, or when the RE-IGN TEST switch is
placed in the GND
full up position.
(5). Panel and Instrument Lights Dimming
Circuit:
When the night lighting system is
installed, a variable positive dc voltage
(0 - 28 Vdc) from the external flight
instruments light potentiometer R110
is applied to the input of the switching
regulator in the dimming unit. The
variable input voltage causes the
switching regulator to vary the positive
dc output voltage applied to and
current flowing through the external
panel and instrument cluster lamps.
This controls panel and instrument
internal lamp illumination. Minimum
regulator output is +2.5 Vdc with an
input of 0 Vdc and +26 Vdc with an
input of +28 Vdc.
(6). Caution and Warning Lights Press-To-
Test Circuits:
Diodes are incorporated in the dimming
unit for all caution and warning light
circuits (described above) to provide
either a required ground or +28 Vdc
input for the associated circuit when
the external PRESS-TO-TEST switch
is pressed. Lamp illumination is
constant during press-to-test opera­
tion; none of the lamps flash during the
check.