APPARATUS FOR SWITCHING WINDINGS OF AC THREE-PHASE MOTOR

摘要

A small and inexpensive apparatus for switching the windings of an AC three−phase motor in which the time required for switching the windings is shortened and the number of semiconductor switch elements is decreased as much as possible.The apparatus for switching the windings of an AC three−phase motor comprises an AC motor provided,on the outside thereof,with terminals interconnecting a plurality of windings constituting each phase winding and the opposite terminals of each phase winding,a winding switching means for switching the interconnecting terminals appropriately,and a power supply for supplying the AC motor with a variable frequency variable voltage.The winding switching means comprises a plurality of three−phase rectifying means where one end of each phase winding is connected with the variable frequency variable voltage power supply and the other end of each phase winding and the interconnecting terminals are connected,for each phase,with the AC side input terminal of each three−phase rectifying means,and a semiconductor switch for opening/closing the opposite ends on the DC side of the three−phase rectifying means.