AC Motor apparatus

An AC motor apparatus comprising:

• a stator having a plurality of unit stator windings arranged in plural phases each phase having first to fourth stator windings;
• first to fourth silicon controlled rectifiers (SCRs) connected in series to said first to fourth stator windings, respectively;
• a control circuit to control said SCRs;
• and
• power supply means for supplying electric power to said first to fourth stator windings through said SCRs;
• wherein said first to fourth stator windings in a phase are fitted in the same slots of an iron core constituting said stator and those have the same size and the same winding pitch, said first and second SCRs are connected in series with said first and second stator windings respectively with the same polarity as that of said corresponding stator windings, a series circuit including said first stator winding and said first SCR and another series circuit including said second stator winding and said second SCR are connected in anti-parallel fashion to form a first circuit, said third and fourth SCRs are connected in series with said third and fourth stator windings with the opposite polarity to said corresponding stator windings, a series circuit including said third stator winding and said third SCR and another series circuit including said fourth stator winding and said fourth SCR are connected in antiparallel fashion to form a second circuit, a plurality of said first circuits forms a first interphase connected circuit and a plurality of said second circuits forms a second interphase connected circuit, said power supply means includes a first power supply for producing a first polyphase AC power and a second power supply for supplying a second polyphase AC power, the corresponding voltages of corresponding phases of said first and second power supply sources have a phase difference of about .pi./2, said first power supply supplies electric power to said first interphase connected circuit and said second power supply supplies electric power to said second interphase connected circuit, and said first to fourth SCRs are controlled at a given firing angle.