SU1056529A1 - Device for plasma-arc cutting - Google Patents

Abstract

INSTALLATION FOR GSHAZMENNODUGOVOY CUTTING comprising a power transformer with povshennym-diffusion, to the secondary winding of which is connected to a rectifier and an electrode of the plasma torch and the oscillator, vklyuchanldy up transformer whose output is shunted spark arrester and is connected in series with the capacitor and the primary winding of the high-frequency transformer, one from the ends of the secondary winding of which is connected to the plasma torch electrode, and the second is connected to the negative pole of the mitel, the output of which is shuntiro a capacitor, characterized in that, in order to increase reliability, the input of the step-down transformer of the oscillator is connected directly to the secondary winding of the power transformer. (L

Description

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The invention relates to (welding technology, devices for plasma cutting and welding intended for use in various sectors of the national economy. A known installation for electric arc metal processing, comprising a power transformer with increased scattering, the secondary winding of which is connected to an electrode through the secondary winding of an additional low power transformer replacing the U oscillator. J Closest to the proposed invention according to the technical essence and the achieved result is an installation for plasma-arc cutting, containing a power transformer with increased scattering, with a secondary winding to; a BbmpHMHTejib and a plasma torch electrode, and an oscillator that includes a step-up transformer, whose output is spliced by a spark and connected in series with the capacitor and the primary winding of the high-frequency transformer, one of which ends is secondary to the coils of which is connected to the plasma torch electrode, and the second is connected to the negative pole of the rectifier whose output is bridged of capacitors 2. In this apparatus, power oscillator effected by the network via an intermediate relay contacts, which is carried off by the current switch. The disadvantage of such an installation is low reliability, complexity and increased cost. . - Nazca reliability due to the presence of intermediate relays and relays that control the operation of the oscillator. The same reasons are due to the complexity and complexity of the installation. The aim of the invention is to improve the reliability of the installation for plasma-arc cutting. This goal is achieved by the fact that in a plasma-arc cutting installation containing a higher-power power transformer, the secondary winding of which is connected to the rectifier and the plasma torch electrode, and an oscillator, which includes a turn-on transformer, the OUTPUT of which is shunted by a spark and connected in series with the capacitor and the primary winding of the high-frequency transformer, one of the ends of the secondary winding of which is connected to the plasma torch electrode; and the second is connected to the negative pole of the rectifier, the output of which is bridged by a capacitor, the input of the upstream 7 oscillator transformer is connected directly to the secondary winding of the power transformer. The drawing shows the proposed installation. The plasma arc cutting machine contains a power transformer with increased scattering, the input 2 of which is connected to the mains. An output 4 is connected to the output 3 of transformer 1, the positive output of which is connected to product 5, and the negative output is connected to the electrode 6 of the plasma torch 7. The secondary winding of the high-frequency transformer 8, which is part of the negative 9, is switched on in series with the electrode 6 of the plasma torch 7. transformer 8 is connected in series with condenser 10 with a spark discharge 11 and forms an oscillating circuit connected to the secondary winding of an additional step-up transformer 12. Transform primary winding Ator 12 is connected directly to the code 3 of transformer 1. The secondary winding of transformer 8 is connected to product 5 by means of a capacitor 13. The installation works as follows. When voltage is applied to input 2 of transformer 1, the corresponding voltage from output 3 of transformer T is applied to the primary winding of an additional step-up transformer 12. Capacitor 10 is charged until its voltage on the windings is sufficient for a spark gap. 11. After this, the capacitor 10 begins to discharge on the oscillating circuit of the oscillator 9. Since the resistance of the spark discharge in the discharge capacitor 11 is small, the secondary winding of the transformer 12 turns out to be almost closed that

shortly through discharge 11. Cohn; The capacitor 1.0 is discharged through the discharge 11 to the inductance of the primary winding of the high-frequency transformer 8. After the discharge of the capacitor 10 is electromagnetic energy, the accumulated inductance of the winding changes into an electric one that ensures the charge of the capacitor 10.

A current flows through the circuit again.

but in the opposite direction. The process then repeats and periodic fluctuations in current and voltage occur. These oscillations will be damped due to scattering of the energy of the circuit. Therefore, the spark in discharge 11 is extinguished. In the next half period, the capacitor is recharged from the transformer) 10 in the opposite direction. The oscillatory process repeats as a group of high-frequency damped pulses that have a relatively large voltage amplitude at the beginning. The pulsed high-frequency current flowing in the primary winding of the transformer 8 induces in the secondary winding of the transformer 8 high voltage and high frequency pulses, brought to the gap between the electrode 6 of the plasma torch 7 and the product 5. When the plasma torch 7 is brought to product 5 the pores For 1-2 m, a gap is provided between the electrode 6 of the plasma torch 7 and the workpiece 5. Between the electrode 6 of the plasma torch 7, connected via the secondary winding of the transformer 8 to the negative pole of the top 4 and the product 5, is connected BoshHKaet cutting arc 4 with positive pole. At the same time, the voltage at the outputs of the rectifier 4 drops from the value corresponding to

idle power transformer 1, to the value corresponding to the operating mode of cutting. This reduction in voltage is caused by the fact that the power transformer is selected with twisted scattering. After the occurrence of the cutting arc, the voltage at the output 3 of transformer 1 drops. Since the primary winding of transformer 12 supplying oscillator 9 is powered directly from the output 3 of power transformer 1, the voltage decreases to that second capacitor10. This voltage is insufficient to cause a spark gap of the discharge gap 11 and the oscillator 9 stops working. If the cutting arc is accidentally broken, the voltage at the output 3 of transformer 1 increases again to the value corresponding to the idle speed of transformer 1. This voltage is enough to allow the oscillator 9 to start working again. If the plasma torch 7 is brought to the product 5 at a distance of 1-2 mm, then the cutting arc reappears.

The described installation provides an increase in reliability as compared with the known technical measures by reducing the number of constituent elements of the structural circuit, excluding from it the contacts of the intermediate automation elements (current relay and intermediate relays). At the expense of the same means, the installation is simplified and cheaper. Timely turn on and

. disabling the oscillator is provided by using new

. sv zay design elements.

Claims (1)

PLASMA-ARC CUTTING PLANT, comprising a power transformer with increased scattering, with a rectifier and a plasmatron electrode connected to its secondary winding, and an oscillator including a step-up transformer, the output of which is shunted by a spark gap and connected in series with a capacitor and primary winding of a high-frequency transformer, one of the ends the secondary winding of which is connected to the plasma torch electrode, and the second is connected to the negative pole of the rectifier, the output of which is bridged a capacitor, characterized in that, in order to increase reliability, the input of the step-up transformer of the oscillator is connected directly to the secondary winding of the power transformer. 1 1056529