Calculation Method of Characteristic by Equivalent Circuit for Pole-Changing Induction Motor with Pole-Amplitude Modulation. Pole Changing from 8-pole to 10-pole by Pole-Amplitude Modulation.

Abstract

A pole-changing induction motor with pole-amplitude modulation allows a speed ratio other than 1:2 using a single winding. Furthermore it has a good energy-saving performance when used for the flow rate control of pump or blower, and also it provides a low manufacturing cost. However, the pole-changing induction motor with pole-amplitude modulation has a problem that its simple calculation method of characteristics has not been presented.A purpose of this paper is to derive the calculation method by using an equivalent circuit in when an 8-pole cage type induction motor is changed into a 10-pole motor by pole-amplitude modulation. In this paper, the authors suggest the equivalent circuit in which the space harmonic effects are considered, because the 10-pole motor has large harmonic magnetomotive forces. This paper also describes a simple determination method of equivalent circuit constants.Torque-slip characteristics and output-characteristics are obtained, and it has been confirmed that they agree well with the experimental values. This calculation method of characteristic is practical and useful for the future designing of pole-changing induction motors with pole-amplitude modulation.