While the engine is running the pulley is rotating, provided that the
connected to the pulley of the engine by a "V" or "poly V" belt, but the compressor does not
operates before being energized.
When the air conditioning system is on, the amplifier supplies current to the stator winding. Then the electromagnetic attraction attracts the hub against the friction surface of the pulley. The friction / friction between hub and pulley, allows the movement of the compressor.
The electromagnetic clutch is mounted on the pulley, where it makes the compressor run only when needed, through the electric current of 12 volts of the battery. This current comes from the relays or the thermostat or the thermistor or from the low and high pressure switches of the system, which can be controlled by the electronic control module of the vehicle.
