Abstract: A rotor for an electric motor includes a core, a plurality of magnets, and a magnet retention cap. The core is rotatable about an axis and defines a plurality of magnet-receiving slots. Each of the magnets is received in a respective one of the magnet-receiving slots. The magnet retention cap is fixed relative to the core and includes a resiliently deformable magnet retention element configured to restrict axial movement of the magnets relative to the core.

Abstract: An apparatus for measuring the work produced by a compressor comprises pressure sensors for measuring the suction and discharge pressures of the compressor and a device for measuring the operating speed of the compressor. The apparatus further comprises a data processor for receiving signals representative of the suction and discharge pressures of the compressor and its operating speed, and generating a signal representative of the work performed by the compressor during a predetermined time interval. Desirably, the data processor is designed to integrate the work output of the compressor over a series of time intervals to generate a cumulative horsepower-hour reading for the compressor over an extended period of time.