Induction motor with free rotating magnets in the rotor

Abstract

We have developed a unique induction motor that has free rotating magnets inside its rotor. Modificating the rotor of conventional 3-phase 4-pole 400 W squirrel-cage induction motor, we have fabricated a prototype motor. In the experimental results of a prototype motor, we have obtained superior performance over existing motors in terms of power factor, efficiency and torque density. The power factor can be controlled to be unity, leading or lagging by changing the supply frequency and/or source voltage. The efficiency of the motor, over wide output power range, is remarkably higher than that of a same size conventional induction motor. Even if in various load conditions, the motor can be controlled to be operated in the optimized power factor and efficiency by changing the source voltage.