Pilatus PC-12, Manual

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Component Maintenance Manual
EFFECTIVITY: ALL 21-00-22
Introduction
Page 13
JULY 21, 2011
SUBTASK 21-00-22-99F-008
2.3 System Component Description and Operation:
2.3.1 The R12 air conditioning system installed on the Pilatus PC12 Aircraft uses the following
major system components:

Compressor Condenser Module Assembly 1250900-4

Evaporator Module Assembly 1250200-42 (L) /-43 (C,R)
2.3.2 The COMPRESSOR CONDENSER MODULE ASSEMBLY (PN 1250900-4) has a rated
cooling capacity of 20,000 BTUH when operating with the other components in the Pilatus
PC12 Aircraft at an ambient temperature of 95°F OAT. Under this condition, the nominal
current draw is 105 AMPS at 28 VDC.
2.3.3 The Compressor Condenser Module Assembly is packaged to meet the aircraft installation
requirements and contains the following major components (refer to Figure 10001):

Compressor Drive Motor

Compressor Assembly

Condenser Coil

Receiver Dryer Assembly

Binary Pressure Switch
2.3.3.1 COMPRESSOR DRIVE MOTOR: The compressor drive motor has a double-ended
shaft and operates on 27.5 VDC power with a rated current draw of 115 AMPS max.
One output shaft drives the R12 compressor and the other end drives the motor
cooling fan. The motor design power is 3.2 HP at 5000-5250 RPM and is specially
designed to provide a high starting torque to overcome the compressor startup
requirements. The motor is a brush commutated permanent magnet design and was
selected for its efficiency, excellent controllability, long life, and low vibration. The
shaft is supported on high speed ball bearings for reliability and friction reduction.
2.3.3.2 COMPRESSOR ASSEMBLY: The compressor assembly contains an R12
compressor and 5.01 inch pitch diameter pulley assembly. The compressor also
features a five piston wobble plate design as well as anti-slugging features that
eliminate the need for a suction trap/accumulator. The compressor has a light-weight
aluminum housing. The pulley assembly is designed for a high strength, positive grip
240L100 timing belt and contains a radial bearing to assure no side loads are
transmitted into the compressor input shaft. The assembly is designed for continuous
operation.