抄録
We have developed a unique induction motor that has free rotating magnets inside its rotor. In the experimental results of a prototype motor, we have obtained superior performance over existing motors in terms of the power factor, efficiency and output torque. The experimental details are as follows. The power factor of the test motor is significantly improved as compared with that of conventional induction motor. The power factor can be controlled to be unity, leading or lagging by changing the line frequency and/or source voltage. It is quite a unique feature, because the power factor of usual induction motor is always lagging. The improvement of the power factor becomes effective not only against the decrease of the current loss but against the decrease of voltage drop in line and the increase of installation capacity. The efficiency of the motor, over a wide output power range, is remarkably higher than that of the same size conventional induction motor. Actually, in ordinary induction motor, the efficiency is reduced as the power and/or the source voltage is decreased. However, the proposed motor is driven in the high efficiency by lower source voltage at lower range of power. The efficiency is improved by reducing the secondary current and the magnetizing current.
