| 摘要 |
PURPOSE:To use a lifting magnet efficiently by adjusting supply currents so that maximum allowable currents commensurate with the operating time of an electromagnet are applied to the electromagnet. CONSTITUTION:When a setting time is set to a shortest value by an excitation- quantity selecting control switch 14, a built-in contact 14a is closed, a main contact 11a for the contact 14a is closed, and a tap capable of supplying magnet currents commensurate with to the operating time is selected. A controller 5 is operated at the position of excitation of a magnet, and a built-in contact 15a is closed. Currents flow through a magnetic coil 10 for an electromagnetic contactor for switching a main circuit by closing the built-in contact 15a, and the coil 10 is excited. When the magnetic coil 10 for the electromagnetic contactor for switching the main circuit is excited, a main contact 10a for the coil 10 is closed, and currents flow through a lifting magnet 9 and the magnet 9 is excited. Since the main contact 11a for an electromagnetic contactor for changing taps is closed at that time, large currents flow through the lifting magnet 9, thus giving the lifting magnet a strong force of attraction.
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