Static Torque Method to Estimate Temperature Rise in High Power Induction Motors

Because of limitations imposed by manufacturer's power supplies and load equipment, factory acceptance test, that is, conventional temperature rise tests are extremely difficult and expensive to perform for large output machines. In those cases alternative methods to estimate the temperature rise and full load losses are considered. In this paper we propose a simple alternative method called "static torque method" suitable for high power induction motors' application such as ship propulsion and which most manufacturers could employ with a minimum capital expenditure. The principle of the method is discussed and temperature rise results from 3 sizes of induction machines are compared with those obtained through conventional full load test. The difference between the results obtained by static method and full load method doesn't exceed 5%.