PW4000 SERIES ENGINES

777 AIRCRAFT MAINTENANCE MANUAL

ENGINE FUEL CONTROL -PMA

EFFECTIVITY BEJ ALL  73-21-00 
Page 21 
D633W101-BEJ  Sep 05/2002 

ENGINE FUEL CONTROL -EEC AND PROGRAMMING PLUG

General
The EEC is a computer that controls the operation of the engine. It attaches to the lower-left fan case with shock mounts. The housing contains two electronic channels that are physically separated internally. The unit weighs about 51 lb (23 kg). Natural convection cools the EEC.
Electrical Connections
Each channel of the EEC has seven electrical connections, three on each side and one on the bottom. Both channels share the inputs of the two connections on the top of the EEC. These are the programming plug and test connector.
The test connection is for testing the EEC with special shop equipment.
Programming Plug
The programming plug selects the proper software in the EEC for the thrust rating of the engine. The plug attaches to engine fan case with a lanyard. When you remove the EEC, the plug remains with the engine.
Pneumatic Connections
Each channel of the EEC has three pneumatic connections on the bottom of the EEC. Transducers inside the EEC supply the related and opposite EEC channel with a signal in proportion to the pressure. These are the pneumatic connections:
*
PAMB -ambient pressure

*
PB -burner pressure

*
P2.5 -LPC exit pressure

*
P2 -fan inlet pressure (EPR)

*
PSPARE -spare connection

*
P5 -LPT exit pressure (EPR) (P4.95).

Training Information Point
The engine wires have these colors to show their purpose:
*
Blue -EEC channel A signals

*
Green -EEC channel B signals

*
Gray -non-EEC circuits

*
Yellow -thermocouple signals.

EFFECTIVITY BEJ ALL  73-21-00 
Page 22 
D633W101-BEJ  Sep 05/2002 

ENGINE FUEL CONTROL -EEC AND PROGRAMMING PLUG

EFFECTIVITY BEJ ALL  73-21-00 
Page 23 
D633W101-BEJ  Sep 05/2002 

PW4000 SERIES ENGINES

777 AIRCRAFT MAINTENANCE MANUAL

THIS PAGE IS INTENTIONALLY LEFT BLANK

73-21-00

Page 24 D633W101-BEJ Sep 05/2002

ENGINE FUEL CONTROL -EEC -FUNCTIONAL DESCRIPTION

General
The EEC is a two-channel computer that controls the operation of the engine. It has two channels, but only one is in control at a time (primary channel). The primary channel changes each time you start the engine.
Power
The EEC gets power from the ELMS or the permanent magnet alternator (PMA).
The ELMS supplies power to the EEC when one or more of these conditions exist:
　
中國航空網(wǎng) m.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：777 AMM 飛機(jī)維護(hù)手冊 發(fā)動(dòng)機(jī)和燃油控制 Engine Fuel and Control PW 777 AIRCRAFT MAINTENANCE MANUAL(14)