| 摘要 |
<p>A controller comprises a driving power source (1) of a variable frequency, an induction motor (2) having a plurality of stator windings (21, 22; 23, 24; 25, 26) provided for each of the phases, and semiconductor switches (311, 321, 331; 312, 322, 332; 313, 323, 333) provided for each of the phases to switch the connections among the plurality of stator windings. The number of series conductors of stator windings provided for each of the phases, is changed by said semiconductor switches. This widens the region of constant output characteristics of the induction motor, and makes it possible to carry out the operation up to a desired high-speed region.</p> |
