Application of Newton-Raphson Method combined with analytical equations for determination of the induction motor equivalent circuit parameters

This paper describes application of modified Newton-Raphson method combined with analytical equations for determination of equivalent circuit (EC) parameters from the motor performance data. In this procedure, two of the total seven EC parameters are estimated using well-known analytical expressions. Values for the five remaining parameters are calculated iteratively using the reduced five-parameter Newton-Raphson method. For obtaining more accurate results, the EC parameters estimated in such a way are taken as new initial estimates for the seven-parameter Newton-Raphson model. The calculation results are compared with measurement results. All the errors in determination of EC parameters obtained by such model are within an acceptable range.