A compressor assembly for pumping a recirculating refrigerant including a power input shaft, a power output shaft and a clutch disposed therebetween for translating torque from the power input shaft to the power output shaft. The clutch includes a solenoid for generating an electromagnetic force and an actuator including input friction plates mounted for rotation with the input shaft and output friction plates mounted for rotation with the output shaft. The input and output friction plates are adapted for frictional engagement to translate torque between the input and output shafts. The actuator is responsive to the electromagnetic force to initially move along the axis of the input shaft thereby bringing the input and output friction plates into engagement to translate torque between the input and output shafts to actuate the compressor assembly so as to produce a refrigerant discharge pressure. The actuator is further responsive to the discharge pressure to develop a greater force between the input and output friction plates thereby bringing about full torque translation between the input and output shafts.