Parameter estimation of squirrel-cage induction motors without torque measurements

A very simple method for determining squirrel-cage induction motor parameters is presented, and some problems in the determination of parameters with two methods proposed in IEEE Standard 112 are discussed and clarified. The double-cage model is used to describe the motor response for the entire operating range. Equivalent circuit parameters are calculated from data of three tests: no-load test, locked-rotor test and overload test. The method has the advantage of not requiring torque measurements. It is formulated as an iterative algorithm, and has been tested with 16 motors of different power ratings, showing very good convergence. The influence of measurement errors on the stability of the proposed method has been studied and its behaviour is very good.