Impedance matrix analysis technique in wound rotor induction machines including general rotor asymmetry

A steady state analysis is developed for a wound rotor induction machine. In this paper the authors derive simple expressions for the mutual and coupling impedance in order to build impedance matrix. The analysis can be used in two ways when dealing with a symmetrical and asymmetrical rotor. The analysis is verified using a wound-rotor motor; the analysis can then be used to investigate asymmetry faults in a wound rotor machine. Experimental results (torque and current characteristic) are compared with computer predictions for the machine with both open-circuit and short-circuit faults.