| 摘要 |
PURPOSE:To contrive a device to be accommodated to an operating mode in a short period, by arranging a diode and a resistor in series, and by setting a switch in parallel with them to turn the switch OFF at the time of the fall of current. CONSTITUTION:An electromagnet power-supply device is composed of a rectifier 3 and its transformer 2, a reactor 4, a capacitor 5, a chopper circuit 6, a diode 7, and the like, and to the electromagnet coil 8 of a load, current is fed. In this case, a resistor 14 for attenuating load current at the time of the fall of current, and a switch 15 for being turned OFF at the time of the fall of current and for permitting the load current to flow to the resistor 14 side are arranged. Then, the switch 15 is turned OFF, and current fall command 51 for blocking a chopper circuit 6 is used. Then, the control rectifier 3 is previously operated, and necessary DC voltage is kept established, and the chopper circuit 6 is operated to perform the rise of current. When the current comes to a specified value, then the chopper circuit 6 is stopped by the current fall command 51, and the switch 15 is turned OFF to return the current.
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