JPS5545576A - Excitation circuit of electromagnet for welding arc deflection - Google Patents

Abstract

PURPOSE: The excitation circuit which has reduce the excitation current and has made the electromagnet small-sized, by inserting a rectifier in which two commutating elements are connected in parallel and in reverse between the AC power supply for excitation of the electromagnet and the electromagnet, and one direction commutating current regulator by which a current of the commutating element is adjusted.

CONSTITUTION: As far as this excitation circuit is concerned, the phase-shifting device 12, the excitation voltage regulator 13, and the excitation current regulator 14 are formed by the sliding transformer 21, the transformer with a tap 22, and the sliding resistor 23 which is connected to one of the output terminals of the transformer 22, respectively. Also, the rectifier 15 is formed by the commutating elements 24 and 25 which are connected to the resistor 23 in parallel and in reverse each other, while the one direction cummutating current regulator 16 is formed by the sliding resistor 26 connected to the element 24, and the sliding resistor 27 connected to the 24, and the sliding resistor 27 connected to the element element 25. And in order that the waveform of an excitation current of the electromagnet for arc deflection to the following electrode can be made asymmetrical by means of this excitation circuit, the half-period electromagnetic current of the same direction as the following arc current is reduced by adjusting the resistor 26 or 27 depending upon strength of the preceding arc current. Accordingly, it is possible to obtain the waveform of magnetic density having a nearly symmetrical area to the time axis, and the excitation current can be reduced.

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