(3)
Slide sleeves over wires and out of the way. Complete splice assembly.
(4)
Clean and insulate the splice area per Method 1, steps (1), (2), and (3).
(5)
Slide small sleeves over tape until they are butted against ends of splice. Shrink into place.
(6)
Center large sleeve over assembly. Shrink into place.
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501 Insulation Method 2
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ELECTRICAL POWER PRECAUTIONS - MAINTENANCE PRACTICES
1. General
A. The electrical power precautions are contained in Chapter 20, Standard Wiring Practices, document D6-54446 (Ref 20-00-10).
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AC GENERATOR DRIVE SYSTEM - DESCRIPTION AND OPERATION
1. General
A. The two engine driven 400 cycle ac generators are rotated by constant speed drive systems to obtain a generator speed of 6000 rpm. The drive system contains a mechanical differential hydraulically controlled drive unit attached to the aft side of the engine accessory gear case. (See figure 1.) The drive unit acts as the support for the ac generator.
B. Manual controls, monitoring lights and dial indicators for the drive systems are on the forward overhead panel in the control cabin. (See figure 1.) Lights indicate drive low oil pressure and high oil temperature. Dial indicators show actual drive oil temperature and drive oil temperature rise, by means of a selector switch. A disconnect switch provides for stopping a system through an electrical solenoid-operated mechanical disconnect device included in the drive unit. Sensors in the drive obtain a charge pressure indication and the out and in temperatures of the oil to and from the cooler.
C. The oil within the drive unit functions to absorb the heat, to serve as the lubricant, and also to transmit some torque as the hydraulic medium. Oil is forced through a line filter and external cooler by a scavenge pump which picks up hot oil as it collects in the sump, coming from drains, from seepage and from lubrication points in the drive unit. Cool oil is returned to the al1-attitude reservoir by the scavenge oil system. The swirl chamber in the reservoir removes and expels air carried by the oil. The normal temperature rise of the oil through the drive unit is about 10oC at continuous full load with an inlet oil temperature of 120oC, at normal input speeds.
D. A charge pump moves oil from the reservoir to the governor and control cylinder and replenishes oil as required at the stationary port plate and at various lubricated surfaces. A charge relief valve restricts oil passage downstream from the port plate to ensure adequate supply of oil for the control, for the variable and fixed hydraulic displacement units, and for the lubrication nozzles. Separately confined oil in the input spline cavity lubricates the splines incidental to the input shaft and the connection to the engine.
E. The input shaft accepts torque supplied by the engine at various speeds and delivers torque to the input end of the planetary differential gear unit in the drive. Depending on the difference between output speed and 6000 rpm, the variable displacement hydraulic unit will boost or retard the speed of the planetary differential output gear to maintain a 6000 rpm output speed, as required by the governor.
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F. The governor is driven directly by a gear on the output shaft and wil1 port oil to, or drain oil from, the control cylinder depending on the required speed correction. The piston in the control cylinder wil1 adjust the angle of the wobbler as required by the variable displacement hydraulic unit. It is the angular position of the wobbler that determines the amount and direction of the oil delivered to the fixed unit and the consequent speed adjustment made to the differential gears.
2. Constant Speed Drive Unit (CSD)
A. Each engine-driven generator is supported by and driven through an in-line type, variable ratio drive unit which transmits the torque to drive the generator at a constant speed from the variable speed accessory drive pad on the airplane engine. The drive unit or constant speed drive (CSD) is attached to the engine with a quick-attach-detach (QAD) device consisting of three interlocking threaded rings which takes the place of mounting studs (Fig. 1). The CSD output end attaches to the ac generator by means of 12 studs. The generator mounting nuts only need to be loosened to remove the generator. A typical engine-driven CSD and generator installation is shown in figure 1. The accessory mounted ring of the QAD device is attached to the drive unit with studs. The engine mounted ring is fastened to the accessory drive pad on the engine with flat head screws. Gaskets, not shown on Fig. 1, make the input spline cavity oil tight.
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