DISC 0385888 - Caterpillar

Illustration 1 g00466903
(1) Compressor (2) Magnetic clutch and pulley assembly
Illustration 2 g00645443
(2) Magnetic clutch and pulley assembly (3) Drive plate (4) Compressor shaft (5) Bearing (6) Coil assemblyThe compressor is driven by the engine. A belt connects the engine to the clutch and pulley assembly (2). The pulley assembly is located on the clutch. The drive plate (3) is fastened to the shaft of the compressor. The clutch and pulley assembly (2) turns on the bearing (5). The clutch and pulley assembly (2) are not connected to the shaft (4). The electric current from the thermostat controls a magnetic field in the coil assembly (6) .The magnetic field pulls the drive plate (3) against the clutch and pulley assembly (2). The clutch and the pulley assembly (2) turns the shaft (4) that operates the compressor. When the current to the coil assembly (6) is stopped, the magnetic field is removed. This allows the drive plate (3) to move away from the clutch and pulley assembly (2). The clutch and the pulley assembly (2) will turn freely on the bearing (5). The sequence of connecting and disconnecting the pulley to the compressor shaft (4) is called compressor cycling. The compressor cycling is controlled by the thermostat. The thermostat is controlled by the capillary tube, which is installed between the fins of the evaporator coil.