Field harmonics in induction motors

CUSPS in the speed-torque curves of induction motors have been attributed to several causes; first, to harmonics in the rotating field; second, to the synchronous locking-in of stator and rotor harmonics as shown by Dreese; and third, to the effect of the slot openings as shown by Kron. The present article is devoted exclusively to the study of the first cause, and indicates that harmonics in the field form do have a very definite effect on the speed-torque curve.