Abstract: A refrigerant compressor of the type driven by a single phase motor capable of operating at a low speed and a high speed. The motor, including four separate windings, a first set of high-speed two-pole auxiliary and main windings, and a second set of low-speed four-pole auxiliary and main windings all wound on the same stator core. Each set of windings is provided with independent line break protectors that enable each set of windings and protector to be optimized without affecting the other. A mandatory low-speed start system is incorporated that insures initial low-speed start even when conditions require high speed operation. Speed switching from one speed to the other is accomplished in the present system while the motor is running without causing interruption of compressor operation.

Abstract: A variable capacity multiple compressor refrigeration system having a hermetic shell containing a first compressor intended to be always running when the system is operating and a second compressor that may be cycled on and off when the system is operating. The separate compressors are mounted to provide a unitary structure resiliently isolated from the common shell. The compressors are arranged in the shell so that their lower bearing portions are always below the level of oil in the sump area of the shell. Both compressors are arranged in the system through common compressor shell inlet and discharge openings.