INDUCTION MOTOR SWITCHABLE BETWEEN SERIES DELTA AND PARALLEL WYE

摘要

An induction motor of the invention, including a single rotor formed in one-piece and first and second stators disposed side-by-side, has a phase-changing device for varying the phase difference between the rotational magnetic field generated by the first stator and that generated by the second stator. The phase-changing device comprises at least first and second short-circuiting switches for short-circuiting or disconnecting the series-junction nodes of the stator windings. The motor presents three different torque curves suitable for starting operation, intermediate speed operation, and normal or steady-state operation by the switching operation of the first and second switches.