Compressor HVAC: Description and Operation

A/C Compressor and Clutch Assembly

NOTE: Internal A/C compressor components are not serviced separately. The A/C scroll compressor is serviced only as an assembly.

The compressor has a variable capacity via an internal valve, which can by-pass volume through the compressor when required. Compressor output varies from 100% to 30% depending on refrigerant demand, the variation being governed by the internal valve within the compressor housing. The compressor has protection in the form of a pressure relief valve and a sensing element for over temperature conditions.





The magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When battery positive voltage is applied to the A/C clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley.
- The magnetic force locks the clutch disc and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate.
- When battery positive voltage is removed from the A/C clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch pulley.