The electric motor operates in the secondary or alternate modes. Relays supply electrical power to the electric motor. During primary mode operation, a clutch disengages the electric motor from the gearbox.
The electric motor is a reversible motor and receives 3-phase 115v ac power. It weighs approximately 42 lb (19 kg). An electrically actuated clutch and a torque limiter are in the motor assembly. The clutch engages the motor with the gearbox in the secondary or alternate modes. The torque limiter prevents too much load on the flap mechanisms. An internal brake engages when the motor is not energized.
Training Information Point
The electric motor contains oil and it is necessary to do servicing. Use the oil fill plug on the side of the motor.
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TRAILING EDGE FLAPS -PDU HYDRAULIC AND ELECTRIC MOTORS
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TRAILING EDGE FLAPS -FLAP LIMIT SWITCH
Purpose
The flap limit switch limits the position of the flaps during alternate mode operation. The flap limit switch also prevents retraction of the slats in the alternate mode until the flaps are fully retracted.
Location
The flap limit switch is on the right flap position sensor gearbox in the right wheel well.
Functional Description
The limit switch is one LRU. It has two internal switches, up and
20.
The up switch controls the sequence of flap and slat retraction in the alternate mode. To do this, the up switch controls the electrical power to the flap and slat electric motors.
During retraction, the up switch permits retraction of the flaps but removes electrical power from the slat electric motor. When the flaps retract to the up position, the up switch removes power from the flap electric motor and permits retraction of the slats.
When the flaps extend to the 20 position, the 20 switch removes electrical power from the flap electric motor.
Training Information Point
The flap limit switch is interchangeable with the slat limit switch.
You install the flap limit switch with the trailing edge flaps in the retracted position. The limit switch rig indicator has a fixed scribe mark and an indicator needle. The indicator needle moves up or down in relation to the scribe mark as the shaft of the limit switch turns. Make sure you align the center of the indicator needle in the rig indicator with the scribe mark when you install the limit switch.
To retract the slats with the flaps extended and disabled, you must install a jumper wire on the electrical connector for the flap limit switch. This permits the slats to fully retract with the flaps extended.
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777 AIRCRAFT MAINTENANCE MANUAL
TRAILING EDGE FLAPS -FLAP LIMIT SWITCH
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TRAILING EDGE FLAPS -TORQUE TUBES AND TORQUE TUBE SUPPORTS
Purpose
The flap torque tubes transmit power from the flap PDU, through angle gearboxes, to the flap transmissions. The torque tube supports hold the torque tubes in place.
Location
There are 28 torque tubes of different lengths for the flap drive system. These torque tubes are in the left and right wheel wells, along the main landing gear beams, and along the rear spar of both wings. Access is through the wheel wells, hinged panels under the landing gear beams, and by extending the flaps.
There are 12 torque tube supports. These supports are along the main landing gear beams, and along the rear spar of both wings. Access is the same as for the torque tubes except for two locations in each wing. The locations in the wings require the removal of a lower skin panel. These locations are at the flaperon support structure and at the main landing gear beam.
Torque Tubes
The aluminum torque tubes are magneformed to steel end fittings. The magneforming process forms the end of the torque tubes around the fittings electro-magnetically.
Torque Tube Supports
The torque tube supports are filled with grease.
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TRAILING EDGE FLAPS -TORQUE TUBES AND TORQUE TUBE SUPPORTS
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TRAILING EDGE FLAPS -ANGLE GEARBOXES
Purpose
The angle gearboxes connect torque tubes that are at different angles to each other. There are six angle gearboxes: 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：777 AMM 飞机维护手册 飞行操纵 Flight Controls 2(36)
