Half-pitch capacitor induction motor

Claim 1

In a single phase, permanent split capacitor 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 inner end of said teeth and having generally axially extending slots formed therein, a squirrel cage winding in said rotor member slots extending between the ends of said rotor member, a main field winding on said stator core member, said main winding forming a predetermined even number of magnetic poles, an auxiliary field winding on said stator core member mechanically angularly displaced from said main field winding and forming the same number of magnetic poles, means for coupling said windings for energization by a single phase source of alternating current, and a phase-displacing capacitor coupled in circuit with one of said field windings thereby providing a two-phase motor: the improvement wherein said inner ends of said teeth have equal angular extent and said teeth are equal in number to twice the number of said poles, said main field winding comprising a plurality of coils equal in number to the number of said poles, said main field winding coils respectively embracing alternate consecutive ones of said teeth, said auxiliary field winding comprising a plurality of coils equal in number to the number of said poles, said auxiliary field winding coils respectively embracing consecutive alternate teeth respectively intermediate said first-named alternate teeth, there being one coil only on each said tooth thereby providing a half-pitch winding for said motor, said main and auxiliary field windings having substantially equal ampere turns and substantially equal pitch thereby providing a balanced two-phase winding.