F
I
S
La
456PQRST Tw
789UVWXY
. 0+/-Z SPDEL / CLR
P/A SERIAL NO. BOEING
NUMERIC KEYS ALPHA KEYS
CONTROL DISPLAY UNIT (CDU) YAW DAMPER MODULE
B
C
Yaw Damper System - Component Location
Figure 1 (Sheet 1)
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MAINTENANCE MANUAL
UPPER RUDDER POWER CONTROL MODULE (ACCESS
RUDDER PANEL 324HL/324HR)
ACTUATOR (EXAMPLE)SEE D ENGAGE SERVO VALVE
ELECTRO-HYDRAULIC SERVO VALVE
CONTROL MODULE (ACCESS PANEL 324DL/324DR) LOWER RUDDER POWER RUDDER CONTROL UNIT
SEE D
STA 360
STA FWD RUDDER POWER CONTROL MODULE
240
D
STA
2360
STA
2080
LEFT AND RIGHT FORWARD MODAL SUPPRESSION ACCELEROMETERS (BELOW FLOOR, STA 320)
SEE E
LEFT AND RIGHT AFT MODAL SUPPRESSION ACCELEROMETERS (BELOW FLOOR, STA 2260)
SEE E
ELECTRICAL
MODAL SUPPRESSION
CONNECTOR
ACCELEROMETER E
Yaw Damper System - Component Location
Figure 1 (Sheet 2)
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2) When the yaw damping function is lost.
3) During the ground test mode which is initiated through the Central Maintenance Computer (CMC).
4) During the power-up test.
(3)
Main Electrical/Electronic Equipment Center
(a) The yaw damper modules are in the main electrical/electronic equipment center. The lower module is installed on the E2-2 shelf. The upper module is installed on the E1-2 shelf.
(4)
Yaw Damper Module
(a) Each yaw damper module consists of two digital computing channels (control and monitor) and a servo-amplifier. The module consists of the following functional components: 1) ARINC Receiver - Provides three high-speed and three
low-speed ARINC 429 receiver interfaces for each channel's microprocessor.
2) Control CPU - Provides the digital computing function for the yaw damper.
3) Analog - Provides the output to the rudder power control module and the analog-to-digital and digital-to-analog signal conversion for both control and monitor channels.
4) Input/Output - Provides input and output discrete signal conditioning for the control and monitor microprocessors.
5) EMI Filter - Provides EMI filtering for signal inputs, signal outputs and electrical power inputs for the control and monitor channels.
6) Monitor CPU - Provides the digital computing function for the yaw damper, duplicating the computing of the control channel.
(b) The servo-amplifier provides rudder command signals to the yaw damper electrohydraulic servo valve. Feedback from the linear variable differential transducer (LVDT) position sensor is received by the actuator position demodulator assembly to close the servo loop. The assembly also provides servo loop monitoring, which operates the automatic solenoid disengagement relay.
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(c)
(d)
(e)
(f)
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MAINTENANCE MANUAL
One multipin connector with three inserts is on the rear panel of each module. Two inserts contain the YDS signal pins and low voltage power pins. One insert contains the ground reference pins. Cooling is provided by air from the rack plenum being forced from the bottom to the top of the modules. A hinged front provides access to the interior of the module.The 28-volt dc engage solenoid power (from the YAW DAMPER circuit breaker on P7) is routed from the control panel, through the module auto-disengage relay contacts, to the RPCM. Separate 28 volts dc from two FLT CONT ELEC circuit breakers (P7 panel) is used to drive the auto disengage relay's coils. Module operating power (+5 volts dc and |15 volts dc) and the 26 volts ac LVDT demodulator reference is provided by the Flight Control Electronics (FCE) power supply modules (Ref 27-09-00/001).The fault detection logic in the modules isolates faults to the LRU level within the yaw damper system and interfacing LRUs. When a fault is detected, it is formatted and sent to the CMC. This fault information can be accessed through the CDU.The following messages are displayed on the control display unit. 1) UPPER/LOWER YAW DAMPER FAILURE - The yaw damper module has 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747-400 AMM 飞机维护手册 空调 AUTO FLIGHT(147)
