Abstract: A motor driven compressor is provided with a means through which the internal portion of the motor is maintained at a pressure below atmospheric pressure when the compressor is operating. This reduced pressure within the motor reduces the windage losses of the motor and reduces the noise generated which as a result emanates from the motor. The present invention is most suitable for use in association with a variable reluctance motor connected in torque provided relation with a screw compressor, wherein the screw compressor is utilized as a vacuum pump. The internal portion of the motor is connected in fluid communication with the suction port of the vacuum pump and this association reduces the pressure within the motor and reduces both the windage losses and the noise emanating from the motor.