(1)  
The engine fuel crossfeed valve(s) is (are) a motor actuated butterfly valve(s). The engine fuel crossfeed valve(s) mounts to the rear spar in the center wing fuel tank. The valve(s) body (within the fuel tank) attaches to the actuator (outside the fuel tank) by an adapter shaft. Access to the valve(s) body requires defueling.

 (2)  
The square (preferred) actuator has a 28v dc permanent magnet motor, an electrical connector, "OPEN-CLOSED" limit switches, and a manual override handle. The manual override handle also shows the position of the engine fuel crossfeed valve.

 (3)  
The round (alternate) actuator has a 28vdc motor, an electrical connector, open-closed limit switches, and a manual override handle which serves as a position indicator.

 (4)  
The adapter shaft connects the actuator and the valve body. The adapter shaft consists of an adapter plate and a shaft with a universal joint. The adapter shaft has indexed splines in both ends. This ensures correct alignment of the actuator to the valve. Access to the adapter shaft requires defueling.

 (5)  
The thermal relief valve(s) on the valve body, crack and reseat between 70 to 55 psig.

 (6)  
Applying 28vdc power opens or closes the valve, depending upon the command. Upon reaching the open position, the butterfly plate contacts a stop pin to prevent over-travel. With the valve full OPEN, the open limit switch closes to deenergizing the actuator. Upon reaching the full CLOSED position, the butterfly plate contacts a stop pin to prevent over-travel. This closes the closed limit switch and deenergizes the actuator.

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 28-22-00
 ALL  ú ú 01 Page 5 ú Sep 20/98

A

757
MAINTENANCE MANUAL

ADAPTER PLATE 
SHAFT ADAPTER 
SEE A CROSSFEED VALVE ENGINE FUEL 
BODY VALVE 
FWD 
ENGINE FUEL CROSSFEED VALVE 
A  1 
ADAPTER PLATE  ACTUATOR SCREW MOUNTING  ELECTRICAL CONNECTOR 
ACTUATOR 
HANDLE OVERRIDE MANUAL SCREW BONDING JUMPER 
BODY VALVE  SHAFT ADAPTER  (DRY SIDE) REAR SPAR  FWD  INBD 
1 2  PREFERRED ALTERNATE  A 2 ENGINE FUEL CROSSFEED VALVE 
Figure 3 Engine Fuel Crossfeed Valve 

ACTUATOR MOUNTING SCREW
ELECTRICAL CONNECTOR
ACTUATOR
SCREW
BONDING JUMPER
MANUAL OVERRIDE HANDLE
REAR SPAR
(DRY SIDE)

INBD
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本文鏈接地址：757 AMM 飛機維護手冊 燃油 CHAPTER 28 - FUEL 2(97)