Compressor Clutch

Compressor - General Description:

The electromagnetic clutch engages the compressor when the A/C button is depressed. The clutch consists of a drive plate, pulley, and a coil assembly. The drive plated is bolted to the compressor shaft. The pulley and bearing assembly is press fitted onto the compressor hub, and the coil assembly is screwed to the compressor body. When current flows through the coil assembly, the drive plate is pulled into the pulley by electromagnetic force.

When the coil assembly is not energized, the drive plate separates from the pulley and the compressor stops. A diode is used to protect electrical circuits from voltage spikes. The diode is located in the underhood fuse block.

A thermal link fuse is incorporated into the coil. If the temperature of the coil exceeds 214°C +/- 3°C (417°F +/- 37°F), the link will melt creating an open coil circuit. When the coil is de-energized the drive plate releases the pulley and the compressor stops pumping. A typical coil resistance will measure 3.22 +/- 0.08 ohms at 22°C (72°F).