Compressor HVAC: Description and Operation

A/C COMPRESSOR AND CLUTCH ASSEMBLY

NOTE:
- Internal A/C compressor components are not repaired separately. Install a new A/C compressor only as an assembly. The A/C clutch disc and hub assembly, A/C clutch pulley and A/C clutch field coil are repairable.
- Installation of a new suction accumulator is not required when repairing the air conditioning system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the suction accumulator.

The SC90V variable scroll A/C compressor has the following characteristics:
- Variable capacity function controlled by a suction pressure sensing device
- Fixed and orbiting scroll to provide refrigerant compression
- Non-repairable shaft seal
- A/C compressor uses PAG compressor oil (oil contains special additives necessary for the A/C compressor)
- A/C compressor contains a thermal cut-out switch which senses the A/C compressor housing temperature (switch disengages the A/C compressor clutch if the housing temperature exceeds 120°C (247°F)

The magnetic A/C clutch has the following characteristics:
- Drives the compressor shaft
- When battery positive voltage (B+) is applied to the A/C clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley
- 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 B+ 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