| 摘要 |
PURPOSE:To reduce a rush current flowing through an AC electric apparatus by interrupting a power from the first power source of a variable frequency to an AC electric machine and idling the same, and thereafter supplying a power from a commercial power source to an AC electric machine in synchronism with the phase delayed at a predetermined angle from the first power source. CONSTITUTION:An interrupter 4 and a switch 6 are closed, and a reference signal in correspondence to a frequency fs of a commercial power source 2, imparted from a speed reference generating circuit 8 is afforded to an inverter 1 via an inclination signal generating circuit 9, and a power of a variable frequency increasing smoothly is supplied to an AC apparatus 3. When the acceleration is completed, a switch 6 is opened, and the phase of the inverter 1 is advanced by DELTAPSIR from the phase of the commercial source 2. Thereafter, the interrupter 4 is opened and the AC machine 3 is coasted, and a closing command is imparted so that the interrupter 5 is closed at a time the phase difference becomes zero. |
