Compressor Clutch: Description and Operation

Electro-Magnetic Clutch (A9k1):

Purpose
- Connect the power flow between the vehicle engine and A/C compressor
- Switch off the A/C compressor in the event of a mechanical defect.

Design
The pulley (1) on the drive shaft (4) of the A/C compressor is driven by the poly-V-belt. It turns in the ball bearing (3) around the magnetic coil (5) fastened to the A/C compressor housing. The pressure plate (6) with rubber insert (7) is connected to the drive shaft (4) on the A/C compressor via a splined shaft (8) on which it can move axially.

Function
The pushbutton control module (N19, N22) actuates the electromagnetic clutch (A9k1) and provides power to the magnetic coil (5) to start up the A/C compressor. The magnetic force pulls the pressure plate (6) in against the rubber insert (7) and holds it in place. This closes the power flow between the vehicle engine and A/C compressor. If the power to the magnetic coil (5) is switched off the pressure plate (6) moves away from the rubber insert (7) to its initial position interrupting the flow of power.