Variable speed asynchronous induction motor

In a single-phase asynchronous induction motor including a stator core member having a plurality of substantially equally angularly-spaced, radially inwardly extending teeth respectively defining winding slots therebetween, said teeth having inner ends defining a bore, a rotor member in said bore having a peripheral surface defining air gaps with said ends of said teeth and having generally axially extending slots formed therein, said teeth inner ends having a circular shape with a diameter greater than the rotor diameter thereby forming said air gaps, a squirrel cage winding in said rotor member slots, a main winding on said stator core member, said main winding forming a predetermined even number of magnetic poles, an auxiliary winding on said stator core member mechanically angularly displaced from said main winding and forming the same number of magnetic poles, said auxiliary winding connected in parallel with said main winding, said teeth being equal in number to twice the number of said poles, said main winding comprising a plurality of coils equal in number to the number of said poles, said main winding coils respectively embracing alternate consecutive ones of said teeth, said auxiliary winding comprising a plurality of coils equal in number to the number of said poles, said auxiliary winding coils respectively embracing consecutive alternate teeth respectively intermediate said first named alternate teeth, there being one coil only on each said tooth, the improvement comprising:

• impedance means connected to said auxiliary winding for shifting the electrical phase across said auxiliary winding;
• said rotor continuously being driven during operation by flux created by both said main and auxiliary windings;
• and,
• means for varying said impedance means between a first impedance and a second impedance in response to a condition outside of the rotor during operation between a low rotational speed and a high rotational speed.