| 摘要 |
PURPOSE:To perform a multistaged or a continued control of the subject induction motor at the speed below half of a synchronous speed by a method wherein a bilateral controlling rectifier is provided between the power source and the motor, and this rectifier is properly controlled. CONSTITUTION:A 3-phase power source 1 is converted to a 6-phase one and power is supplied to the induction motor through the intermediary of a bilateral controlling rectifier circuit. At this time, the output of each of the three phases having the electrical angle 2/3pi among the six phases and the output of each of the opposite phase of the output of each of the above three phases are changed over at the frequency twice or above the power source frequency by the six sets of the bilateral controlling rectifiers to be connected to the above outputs, switching control phase revolution is reversed to a power source phase revolution and the staged frequencies ranging from the neiborhood of the power source frequency to half that frequency are obtained, thereby enabling to perform the voltage control of bilateral controlling rectifiers. |
