SU1532224A1 - Limiter of no-load voltage of welding arc power supply source - Google Patents

Abstract

The invention relates to a welding technique, in particular, to limiting the voltage of the idling of the power sources of the welding arc. The purpose of the invention is to increase reliability by simplifying the design and construction of the limiter. The limiter includes a power switching element, an auxiliary voltage source, a touch sensor, a comparator, and a control unit. The touch sensor is made in the form of a resistor bridge. The welding current sensor is contactlessly connected to the welding circuit. When the welding circuit is closed, a control voltage appears at the output of the comparator and is applied to the control unit. The power switching element is triggered and the arc voltage is supplied to the low voltage of the power source of the welding arc. At the same time, the auxiliary contacts of the power switching element protect the input of the comparator from the voltage of the welding circuit and unblock the control circuit of the backup control circuit. At the end of welding, the control unit with the required time delay shuts off the power switching element. Combining the functions of all switching elements in one electromagnetic switch allows to increase the reliability of the entire limiter. 1 il.

Description

The invention relates to the welding technique, in particular, to limit the voltage of the idling of the power sources of the welding arc.

The purpose of the invention is to increase the reliability of the threat of the circuit and the design of 1 limited.

The drawing shows a circuit of a voltage limiter for no-load operation of a source of titanium welding arc.

The limiter contains the main contacts of the I power switching element, which include 1Y between the clamp 2 of the power supply source 2 of the welding arc and the electrode 3. The second clamp 2 of the source has a welded 1 detachable 4 n one of the clamps of the auxiliary 1 source of duty and 1p and 5 . .Between

source 5 is ON),

form que a bridge. The cerv) de, itite.) Is made up of resistors 6 i 7, forming two curing bridges, and the second de.1. Tel impulse I forms two other axes i bridge 13 is composed of 13 cut 1 stor (And 1 1 to 1 tact e.1 ektrod-1zde.e. The middle point is indicated 1 x and 1 p 1 2 1 D C ONLY b to the inputs A B KON of the loading actuator 9, the output of which is not with the equalizer P1 Yu. - body contacts AND of the power switch of the o-) element switch to) (tr). ipyi M stump e.1ektr () D () m 3 X () D ()

com.arator 9. In welding to) ie) contactless K.K) Che 2 SVAROCH O (1

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current. The unit K) controls the operation of the power switching element 13 by switching it on when the welding circuit is closed, holding it in the on state during welding and for the duration of holding the non-reduced running voltage, as well as back-up switching of the switching element during emergency operation of the latter. For this, unit 10 includes a backup protection circuit, which in the normal mode is blocked by the auxiliary contacts 14 of the power switching element 13,

The limiter works as follows.

As long as the welding circuit is not closed, the voltage at input A of comparator 9 exceeds the voltage at input B, since all the nagging of source 5 is released at the terminals of the limiter (between electrode 3 and product 4). (The resistances of resistors 6 and 8 are the same, and the resistance of resistor 7 is chosen equal to the sensitivity of the limiter. When the welding circuit closes, the contact resistance of the electrode product becomes equal to the resistance value of resistor 7, the voltage at input A of the comparator 9 becomes lower than the voltage at input B In this case, a control voltage appears at the output of the comparator, which is fed to the control unit 10, which controls the flow of the control current to the circuit of the power switching element 13. This closes the main The pins I of the switching element 13, open its auxiliary contacts T1) 1 11 and close its auxiliary contacts 14. The opening of contacts 1 1 protects the input of the comparator 9 from welding voltage, the closure of the contacts 14 is broken; clearly d) Tc, 1chipi of the control unit 10. During welding, the switching element is maintained in the switched on state due to the influence of the signals of the welding current sensor 12 on the operating voltage of the control 10, while the control unit 10 does not perceive the effect of the comparator 9 with . At the end of welding, the control unit 10 with the required time delay shuts down the power switching element 13, thus the welding circuit is disconnected by contacts 1, the input L of the comparator 9 is connected to the electrode 3 by contacts 11, the circuit of the control unit 10 is blocked;

contacts 14, the limiter returns to its original position.

Compared with the well-known in the proposed scheme, the functions of all switching elements in one electromagnetic switch are combined, the connections between the individual elements are simplified, which determines the high reliability of the proposed limiter.

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Claims (1)

Invention Formula A no-load voltage limiter for the power sources of the welding arc, which are installed in the welding circuit on the side of the electrode, the main contacts of the power switching element and the welding current sensor, which form one output, a limiter switch, a starting element, a touch sensor, an auxiliary standby voltage source, normally open contacts and a control unit, the touch sensor made in the form of a resistor bridge, and the starting element is designed as a voltage comparator, with two arms connected to the bridge the first and second resistors connected in series with each other, and the free terminals between the first and second terminals of the auxiliary source, with the first terminal of the auxiliary source being the second output terminal of the limiter, the connection point of the first and second resistor is connected to the first input of the comparator, and to the third shoulder of the bridge connected to the third resistor, one output of which is connected to the second terminal of the auxiliary source, and the second terminal to the second input of the comparator and through normally closed contacts to the first output terminal of the limiter, the output terminals form the fourth bridge arm, the output of the comparator is connected to the first input of the control unit, the output of the control unit is connected to the input of the power switching element, and the second input of the control unit is connected to the welding current sensor, characterized in that, in order to increase reliability by simplifying the circuit and design of the limiter, the power switching element is made to be combined with normally closed and normally open and contacts, the latter being included in the control circuit of the control unit backup-off circuit. 2