(d)
There are three different steps of ram air modulation as determined by three airplane positions. Fixed positions are obtained when the airplane is on the ground and on takeoff. During flight the openings vary according to airplane operation.
(2)
AIRPLANES WITH RAM AIR EXHAUST LOUVERS
(PRE-SB 21-1123);
Ground Operation
(a) When the airplane is on the ground the landing gear safety relay and the air-ground relay complete a circuit to the open side of the actuator and open all circuits to the close side. If the modulation panel and exhaust louvers are not already full open they will drive full open and the actuator position switches will move to the positions shown in Fig. 2. The deflector is mechanically linked to the inlet modulation panel and will be fully extended at this time. At the same time another position switch (switch 3) in the actuator completes a circuit for the RAM DOOR FULL OPEN light.
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A 737-300/400/500MAINTENANCE MANUAL
28V DC
28V DC
115V AC
28V DC
28V DC
RAM AIR ACTUATOR
AIRPLANES WITH "RAM MOD CONT" CIRCUIT BREAKER ON P6-4 CIRCUIT BREAKER PANEL
AIRPLANES WITHOUT "RAM MOD CONT" CIRCUIT BREAKER ON P6-4 CIRCUIT BREAKER PANEL
Ram Air Modulation System Schematic
Figure 2 (Sheet 1)
A54142
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
MODULATION DEFLECTOR RANGE RANGE
POSITION AIRPLANE POSITION FLAP SWITCH POSITION * RAM AIR ACTUATOR POSITION ACTUATOR POSITION VALVE TURBOFAN POSITION PANEL MODULATION POSITION DEFLECTOR
1 2 3 4
GROUND ON DOWN OR UP
1 OPEN OPEN FULL EXTENDED
TAKEOFF DOWN
2 TO MOVES OPEN STAYS OPEN NORMAL TOWARD MOVES RETRACTED
TAKEOFF AFTER UP
3 1 TO MOVES CLOSES OPEN 1 NORMAL MOVES TO RETRACTED
CRUISE UP
1 3 AND 4 BETWEEN MODULATES CLOSED STAYS 1 AND CLOSED NORMAL OPEN BETWEEN MODULATES RETRACTED
APPROACH LANDING DOWN
3 TO MOVES OPENS OPEN NORMAL MOVES TO RETRACTED
DOWN TOUCH- DOWN
MOVES 1 OPEN STAYS OPEN TO FULL DRIVES EXTEND TO FULL DRIVES
* SWITCH POSITION IS SHOWN FOR AIRPLANE ATTITUDE AFTER THE ATTITUDE HAS BEEN ATTAINED
ACTUATOR POSITION REMAINS AT 2 IF AMBIENT CONDITIONS AND/OR HARDWARE CONDITION ARE SUCH THAT REQUIRE MAXIMUM RAM COOLING. THIS PREVENTS MODULATION PANEL MOVING FARTHER TOWARD CLOSED
Ram Air Modulation System Schematic
Figure 2 (Sheet 2)
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A
737-300/400/500MAINTENANCE MANUAL
ACTUATOR RAM AIR
1 LOUVER EXHAUST RAM AIR
CABLE CONTROL
STOP DEFLECTOR FORWARD PANEL CRANK AFT PANEL PANEL OPEN MODULATION CABLE CONTROL ROLLER
BODY SKIN
DEFLECTOR ROD LINK EXTENSION SPRING INLET SCOOP ASSEMBLY ARM PANEL CLOSE MODULATION
GROUND POSITION QUADRANT MODULATION PANEL RAM AIR INLET
STOP DEFLECTOR
AFTER TAKEOFF TO FLAPS UP POSITION 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737-300 400 500 AMM 飞机维护手册 空调 AIR CONDITIONING 2(41)
