Analysis of multilayer rotor induction motor with higher space harmonics taken into account

The paper presents a consistent electromagnetic theory of a multilayer rotor induction motor with distributed parameters. Equations describing the two-dimensional field distribution in the rotor have been used to obtain recurrence relations for the resultant rotor impedance. These relations include the higher space harmonics produced by the stator MMF curve. The classical T configuration equivalent circuit has been extended and adjusted to model a multilayer rotor. Positive- and negative-sequence currents have been taken into account and impedances for forward- and backward-travelling field have been found.The method of the performance calculation for a multilayer rotor induction motor, including current assymetry and higher space harmonics, has been worked out. The approach presented may be helpful in the analysis and synthesis of induction machinery with specially constructed rotors (secondaries). The existing theory has been developed and generalised.