| 摘要 |
PURPOSE:To make possible to alter the number or turn or a stator winding even during operation by performing interconnection of stator windings such that a preset stator winding is short-circuited and subsequently disconnected from the circuit during increasing process of rotational speed whereas the operation is reversed during decreasing process of the rotational speed. CONSTITUTION:When a transition is made from low speed region to high speed region, all stator windings Ciu are connected in series because poly-phase series contactors (i-1)MSu are turned ON in the low speed region. When the rotational speed of motor increases to make a transition to high speed region, number of turn of phase coil is required to be decreased and thereby an appropriate number of a plurality of stator windings are disconnected. In other words, opposite ends of objective stator windings are short-circuited by turning poly- phase short circuit contactors M(i-1)Nu and a double current path is formed at the part of the stator winding Ciu to be disconnected, and then the poly-phase series contactors (i-1)MSu is turned OFF in a quite short time thus opening the objective stator winding Ciu part. |
