VSV
The EEC uses a torque motor driver to control the variable stator vane (VSV) actuator. The EEC receives feedback of the actuator position.
2.9 Bleed Valves
The EEC uses a solenoid driver to control the pneumatically operated 2.9 bleed valves. The EEC receives feedback of the valve position from thermocouple probes.
TCA Valves
The EEC uses a solenoid driver to control the pneumatically operated turbine cooling air (TCA) valves. The EEC uses a torque motor driver to control the actuator of the fourth valve. The EEC receives feedback of the actuator position.
TCC Valves
The EEC uses a torque motor driver to control the turbine case cooling (TCC) valves actuator. The EEC receives feedback of the actuator position.
Nacelle Zone Vent Valve
The EEC uses a solenoid driver to control the position of the nacelle zone vent valve. The EEC receives feedback of the valve position.
73-21-00
Page 17 D633W101-BEJ Sep 05/2002
ENGINE FUEL CONTROL -ENGINE INTERFACES
Programming Plug
The programming plug selects the EEC rating logic with pins. It attaches to the EEC.
EFFECTIVITY BEJ ALL 73-21-00
Page 18
D633W101-BEJ Sep 05/2002
PW4000 SERIES ENGINES
777 AIRCRAFT MAINTENANCE MANUAL
ENGINE FUEL CONTROL -ENGINE INTERFACES
EFFECTIVITY BEJ ALL 73-21-00
Page 19
D633W101-BEJ Sep 05/2002
ENGINE FUEL CONTROL -PMA
General
The permanent magnet alternator (PMA) supplies power to the EEC. It also supplies an analog N2 speed signal to the EEC. The PMA attaches to the front of the main gearbox.
Physical Description
The PMA contains two three-phase coils for power. It also contains two single-phase coils for N2 speed signals. Fan air cools the PMA and the gearbox turns it.
Functional Description
Each EEC channel gets power from one of the alternator coils when the engine gets to 5 percent N2. Each EEC channel also gets an analog N2 speed signal from one of the speed sensor coils. The EEC sends analog and digital N2 speed signals to airplane systems.
Training Information Point
You should use the special removal tool when you remove the PMA rotor. The tool will prevent damage to the PMA carbon seal in the main gearbox. Seal damage can cause high oil consumption.
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