Computation of equivalent circuit parameters of nine-phase induction motor in different operating modes

The nine-phase squirrel-cage induction motor designed for 4-pole operation can also be utilized to operate in 3 phase, 12 pole configuration by rearranging the stator winding connections using the pole phase modulation technique. The 9 phase 4 pole configuration can be used for extended high speed and low torque requirement, whereas the 3 phase, 12 pole arrangement can be utilized for low speed and high torque applications. By switching from one stator winding configuration to another, the nine-phase induction machine can be used for high torque, low speed and extended high speed range and low torque requirements in such applications as the electric vehicle and high speed elevators. In this paper, two comprehensive methods are presented to determine the parameters of the 36 stator slots machine in the two configurations. The parameters calculated using the magnetic circuit analysis and the field analysis using Finite Elements methods are validated by experimental results.