Equivalent rotor impedance of sheet-rotor induction motors

A theory is developed which allows the equivalent resistance and reactance of sheet rotors of various geometrical configurations to be determined. Two factors are presented which relate the resistance to that of a simple rotor with zero-resistance end rings and the reactance to the magnetising reactance. The analysis assumes a sinusoidal travelling current-density wave at the stator surface but the treatment of winding harmonics is indicated. The most common forms of sheet rotor are considered as special cases. Experimental evidence is given in support of the findings.