A Pilot Arc Current Circuit of Plasma Cutting Power Supply

Abstract

The invention provides a guide arc current circuit for a plasma cutting power supply, which is provided with a double-inductance overlapped reactor. By the aid of an existing reactor iron core of a main plasma cutting arc current circuit, inductance double overlapped with the main circuit is obtained in a plasma guide arc current circuit, the inductance value of the guide arc current circuit is effectively improved, follow current of plasma guide arc current is stable, arc breaking at low current is avoided, low-current high-frequency arc for triggering guide arc is immediately changed into plasma guide arc inside a cutting torch under the action of double overlapped inductance follow current in the moment of arc striking, the plasma guide arc current can still be kept constant and stable even if high-frequency arc is extinguished, high-frequency interference is decreased, high-frequency discharging trigger time is shortened, arc striking success rate is increased, and the plasma guide arc is rapidly transformed into constant-current plasma cutting arc.

Description

Technical field [0001] The invention relates to a plasma cutting power supply, especially a circuit in which a pilot arc current is generated. Background technique [0002] In the prior art, the circuit for generating the plasma pilot arc current by the plasma cutting power supply adopts a single-inductor freewheeling structure. Due to the small inductance, the stored electric energy is not large enough. After the high-frequency small current that triggers the plasma pilot arc crosses zero or is cut off, the plasma pilot arc will break and cannot be transferred into a normal plasma cutting arc. In order to improve the stability of the plasma pilot arc current, it is necessary to adopt a solution to increase the inductance of the main circuit reactor of the cutting arc or to prolong the high-frequency discharge time of the pilot arc trigger circuit. In the above first scheme, since the plasma pilot arc current is very small, the arc is easy to break, and the plasma cutting a...

AI Technical Summary

Problems solved by technology

In the above-mentioned first solution, since the plasma pilot arc current is very small, the arc is easy to break, and the plasma cutting arc current value is more than 3 times the pilot arc current value. In order to improve the stability of the small current pilot arc, increase the high current reactance of the main circuit The inductance of the inductor is unreasonable, resulting in a waste of ferromagnetic materials and conductor materials in the main circuit

In the above second scheme, the increase of high-frequency discharge intensity and the prolongation of high-frequency discharge time will bring greater high-frequency interference and cause damage to the safety of people and equipment

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