| 摘要 |
PURPOSE:To enable a motor to be quickly re-started, on restart after temporary service interruption, by applying output voltage control function also to the side of an inverter. CONSTITUTION:When momentary service interruption is generated, then feed is stopped by a converter 30. Also after the momentary service interruption is released, residual voltage is left in a DC intermediate-circuit 4, and also at the terminal of a motor 14, the residual voltage is generated. According to the direct current detecting action of a voltage sensor 5, a switch 10b is made, and on an inverter 9, the output waveform of a frequency/voltage control circuit 10d is worked. The output waveform is a PWM waveform for applying voltage control function to the inverter 9. When output voltage is established, then the switch 10b is broken, and a switch 10a is made, and the inverter 9 is controlled by the same PAM mode as a conventional one.
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