High Efficiency Single Phase Motors

Since the energy efficiency ratio (EER) of the air conditioning system is dependent on the efficiency of the motor in addition to the performance of the refrigerant system. the motor efficiency can be viewed as a source of EER improvement. The amount of motor efficiency improvement obtainable is in turn dependent on the motor material characteristics and the motor size or volume which is usually described as D2L. Most of the single phase air conditioning applications today use permanent split capacitor motors. This paper shows the relative efficiency improvement obtainable in PSC motors as one makes trade-offs in motor stack height, capacitor size. and steel grade. The results show that if a 5 to 7 point efficiency improvement is required. starting from an existing 80.0% to 82.0% efficiency level. major design changes in the motor are required. A substantial increase in total motor content in terms of size. conductor volume, and capacitor size is required. INTRODUCTION ~ith the advent of this era of the "Energy Crisis" nearly every technical journal in print has some article dealing with conservation of energy. Legislation covering energy use has been introduced from municipal to federal levels. No longer can society be permitted to knowingly use more energy than necessary when more efficient methods are technically and economically feasible. To place the problem in perspective, the following studies show the trends in energy use in the United States. In 1968 the total national energy consumption was divided as follows: ·