| 摘要 |
PURPOSE:To start the motor without slipping the same by a method wherein an increase rate of an oscillation frequency of a variable voltage-variable frequency inverter to time is set beforehand, and the oscillation frequency is adapted not to exceed the setpoint. CONSTITUTION:The frequencies of a number of the rotations of the induction motor 6 which are detected by a speed generator are applied to an operational amplifier 24 through a resistor 36, an operational amplifier 25 and a resistor 38. When the slips take place in the induction generator 6, a switch 44 is closed and an output of an operational amplifier 23 is applied to an operational amplifier 22 through an amplifier 26, the switch 44 and a resistor 31. The operational amplifier 22 integrates the outputs of the operational amplifier 26 and adds them to a voltage of a power source 28 and after that, feeds them out to a higher orfer preference circuit 34. The higher order preference circuit 34 feeds the output of the operational amplifier 24 to the variable voltage-variable frequency inverter oscillator 10, controls the frequencies of the inverter 5 and controls the number of the rotations of the induction motor 6. |
