The Rating and Appication of Motors for Refrigeration and Air Conditioning

This paper describes the procedure and practical results to date in applying single-phase motors to refrigeration compressors. The applications are primarily torque applications, temperature considerations being of secondary importance. A line of high-torque motors has been developed to meet the high starting and accelerating torques demanded by the compressors. Utilization of these torques results in running loads considerably higher than rated name-plate loads, without exceeding safe operating temperatures for the insulation life requirement. To meet these requirements a revised method of rating refrigeration motors on a starting and accelerating torque per horsepower and a starting efficiency basis is described. This method more clearly specifies a motor so that a more satisfactory application would be obtainable both from the standpoint of the user and the public utility company or code authority.