Investigation of parameter characteristics for induction machine analysis and control

This paper presents an investigation of induction motor parameters based on improved measurement and analysis techniques. The knowledge gained from the identification of parameter variations over the entire speed range, and especially in the low slip region, will be valuable to engineers involved in drives system design, control and operation. The standard locked rotor and synchronous speed tests are implemented with a variable voltage supply; the former test is performed to identify the variation of stator leakage reactance with stator current and the latter test to determine the variation of iron loss and magnetizing inductance with air-gap voltage. A run up to speed test is conducted to ascertain the behaviour of the rotor parameters with slip and thereby rotor frequency. The investigation was carried out on both single-cage and double-cage three-phase induction machines.