777 AMM 飞机维护手册 电源 Electrical Power(15)

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When you install a new QAD coupling, align the ring index mark and the adapter index mark so the IDG can go in. When you install an IDG, turn it so that the IDG index mark aligns with the ring index mark. This should align the IDG index pin with the QAD coupling index pin hole.
The IDG is very heavy. It weighs approximately 140 lbs (63 kgs). You must get the correct torque on the ring to prevent damage to the mating surfaces of the QAD coupling and the IDG.
At regular times, you must make a check of the QAD coupling. You must make sure that the IDG is locked in the QAD ring. You must make sure the tension bolt torque is correct. If the IDG is loose in the QAD coupling, vibration can cause damage to the QAD ring, the IDG mounting flange, and the IDG input seal.
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777 AIRCRAFT MAINTENANCE MANUAL

GENERATOR DRIVE -IDG QAD COUPLING

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777 AIRCRAFT MAINTENANCE MANUAL

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GENERATOR DRIVE -IDG AIR/OIL HEAT EXCHANGER AND VALVE

General
The IDG air/oil heat exchanger makes the IDG oil cool before it goes to the fuel/oil cooler. The fuel oil cooler makes the oil cooler and heats the engine fuel.
The air/oil heat exchanger valve controls the flow of engine air through the heat exchanger. The air/oil heat exchanger valve has these components:
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Air inlets

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RVDT

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Servo fuel ports

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Oil ports

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Position indicator

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Torque motor

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Electrical connector.

See the oil distribution section for more information about the fuel/oil cooler (SECTION 79-20 ).
Air/Oil Heat Exchanger
The air/oil heat exchanger is a tube-and-fin type. An oil inlet tube lets oil into the heat exchanger. An oil outlet tube lets oil come out of the heat exchanger.
The air/oil heat exchanger has a pressure relief valve (not shown). If the heat exchanger is blocked, the pressure relief valve lets the oil flow directly from the inlet to the outlet.
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Air/Oil Heat Exchanger Valve
The air/oil heat exchanger valve has two butterfly valves. The butterfly valves connect engine fan or 2.5 bleed air to the heat exchanger. A torque motor controls servo fuel flow to operate the valves. An electrical connector connects the torque motor to the EEC. An RVDT monitors the position of the butterfly valves. A position indicator on the outside of the air/oil heat exchanger valve shows the position of the butterfly valves.
A heat shield cover (not shown) protects the air/oil heat exchanger valve from the heat of the engine.
Oil Temperature Sensors
Oil temperature sensors send signals to the EEC. The IDG oil out temperature sensor is in the inlet line of the air/oil heat exchanger. It monitors the temperature of the oil that comes from the IDG. The IDG oil in temperature sensor is in the outlet line of the fuel/oil cooler to the IDG. It monitors the temperature of the oil that returns to the IDG.
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GENERATOR DRIVE -IDG AIR/OIL HEAT EXCHANGER AND VALVE

Functional Description
The EEC uses the IDG oil in temperature signal to make the decision to increase or reduce the airflow to the air/oil heat exchanger. The EEC uses the IDG oil out temperature signal as a backup source. The air/oil heat exchanger valves are normally closed. The EEC sends a signal to the torque motor in the air/oil heat exchanger valve. This controls the servo fuel flow. The servo fuel moves the actuator. The actuator sets the positions of the two butterfly valves. The butterfly valves permit engine fan or 2.5 bleed air to flow through the air/oil heat exchanger.
The EEC gets data about the position of the butterfly valves from the RVDT. A status message shows if the valves do not open when the EEC commands them to be open. The position indicator on the air/oil heat exchanger valve shows the position of the two butterfly valves.
The EEC commands the IDG air/oil heat exchanger valve to fully open during any of these conditions:
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The two IDG oil temperature sensors do not operate

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The engine oil temperature is more than 307F (153C)

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The two elements in the engine fuel temperature sensor do not operate

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Engine fuel flow is less than 2300 lb/hr (1045 kg/hr).

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GENERATOR DRIVE -IDG AIR/OIL HEAT EXCHANGER AND VALVE

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