Induction Machine Rapid Performance Test

Efficiency Test Method A is used in industry to determine the efficiency of induction motors. However, in this method, which is carried out by using a dynamometer, the machine under test shall be brought up to its thermal equilibrium before the data can be collected. This requires running the machine under full load for a considerable amount of time (around 8-h), which implies high cost associated with this test. This paper presents a new simple technique that can significantly reduce the time required for induction machine full-load tests. The proposed technique needs only 30 min of a machine run under full-load conditions. The temperature-speed relationship is the key point in this research work. This relationship is utilized to estimate the machine's full-load temperature. The accuracy of the proposed algorithm is validated by testing two small and two medium-sized machines. The results show acceptable level of accuracy, when they are compared to the corresponding 8-h dynamometer tests conducted on the same machines. The technique can save time and cost associated with the dynamometer test. The proposed algorithm is valid only for totally enclosed fan-cooled type induction motors.