MD Helicopters 369-500, Инструкция по техническому обслуживанию

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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95-30-00
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1999 − 2016 by MD Helicopters, Inc.
to tachometer generator output ac voltage
with a frequency of 66.5 +0.7 Hz), or less.
F. Engine Out (N
1
) Frequency Sensor
Circuits
The N
1
speed-sensing circuit functions at 55%
N
1
RPM (equivalent to N
1
tachometer genera­
tor ac output voltage with a frequency of 36.73
+1.75 Hz) or less. At sensing low N
1
speed, the
N
1
speed-sensing circuit activates the flasher
and tone control circuits with same results
described above (Ref. Autronics EPO Warning
Control Unit).
G. Light Flasher Circuit
At activation, the engine out flasher produces
a pulsating output dc voltage rated at 0.2
ampere, 28 volts, 120 - 180 pulses a minute
with an on time of 50 +15% of the period.
H. Audio Tone Generation Circuits
When the GEN-OFF switch is on and the
flasher and tone control circuit is activated by
N
R
or N
1
sensing, the No. 3 audio tone
generator (audio tone generation and amplifi­
cation circuits) provides an audio tone output
level sufficient for earphones of headsets
without use of an external audio amplifier.
Similarly, audio tone generator No. 1 furnishes
an audio tone for application through the
optional ICS System to headsets. Tone
generator No. 2 is not used. The tone genera­
tors produce negative output pulses at an
audio frequency of 680 - 1700 Hz. Generation
of the output pulses is initiated and inter­
rupted at a rate of l50 +30/minute. Setting the
generator switch to off deactivates the tone
generators through a tone interrupt circuit
(Ref. Tone Interrupt Circuit). Audible warning
tones No. 1 and No. 3 are activated and
controlled by either N
1
or N
R
sensing.
I. Tone Interrupt Circuit
An audio enable ground from the generator
switch to the tone interrupt circuit allows all
tone generators to function, with N
R
and N
1
sensing (when the generator switch is on).
With the generator switch off, the enable
ground is not applied to the tone interrupt
circuit, which disables all tone generators.
Turning the generator switch off disables the
audio tone circuits.
J. EPO Audible Warning Horn
The EPO audible warning horn is an electro­
mechanical warning unit that produces an
audible ”beeping” sound in the crew compart­
ment when engine N
1
speed decreases below
approximately 55% N
1
RPM, or N
R
speed
decreases to 98% RPM or less (Models 369D/E
helicopters with C20 engine; for Model 369FF
helicopters with C30 engine, horn activation
occurs at 95% RPM or less) (Ref. Autronics
EPO Warning Control Unit).
(1). Slim-Line instrument panels:
The audible warning horn is mounted
in a lights/switch and horn housing on
the side of the raised top of the center
instrument panel fairing with two
battery temperature caution and
warning light/switch indicators.
(2). T-Panels:
The audible warning horn is mounted
on top of the instrument panel struc­
ture.
K. Automatic Re − Ignition Circuit (Slim − Line
Instrument Panels)
At activation of engine re-ignition, pin U of
the EPO warning control unit provides 28 Vdc
to ground via automatic re-ignition sequence.
16. Voice Warning LRU (600N)
On the 600 Series Helicopter, the Voice
Warning LRU replaces the EPO Unit used on
the 500 Series Helicopters. The voice warning
system has six operational signal characteris­
tics.
A. Engine Out
(1). FADEC in Auto Mode:
The engine out signal is derived from
the FADEC caution warning lamp
driver. This pr28 Vdc to turn on
the engine out light. The LRU, upon
receiving this signal, shall provide the
voice warning ”ENGINE OUT” into the
audio outputs.
(2). FADEC in Manual Mode:
The N
1
signal to the N
1
indicator is
monitored, and after power up, any
deviation below 55% N
1
RPM (9817.5