SU1579680A1 - Apparatus for switching on welding rectifier - Google Patents

Abstract

The invention relates to welding production and is intended to ensure the safe operation of welders and to reduce idle work of rectifier welding. Qi increase in speed and reliability of the device, as well as the elimination of frequent switching off and on the welding rectifier during the welding process. The device for switching on the welding rectifier contains a source of safe direct current voltage and a main switch. The main switch contacts are connected to the power supply circuit of the welding rectifier. The beginning of the voltage winding and the end of the current winding of the intermediate switch are connected to the negative pole of the welding rectifier, and the end of the voltage winding is connected to the negative pole of the safe voltage source. The current winding is connected in series to the welding circuit and is used in the hold mode. The positive pole of the safe voltage source is connected to the positive pole of the welding rectifier through a isolation diode. The main switch control circuit contains a time relay. Switching the operating voltage in the power supply circuit of the welding arc is carried out by a switching element, such as thyristors. Short dead time pauses are damped by the inductive delay element in the intermediate switch. 1 il.

Description

The invention relates to welding production and is aimed at ensuring the safe operation of welders and reducing idle work of welding rectifiers.

The purpose of the invention is to increase the speed and reliability of the device, eliminating the frequent disconnections and inclusions of the welding rectifier from the network.

The drawing shows a diagram of the proposed device /

The device consists of a welding transformer 1 with a rectifier 2, a source of safe DC voltage 3, the negative pole of which is connected to the end of the winding 4 of the voltage of the intermediate switch 5, and the positive pole through the isolation diode 6 with the positive pole of the rectifier 2. The connection point of the winding of the voltage and current winding 7 of the intermediate switch 5 is connected to the negative pole of the rectifier 2. The current winding 7 is connected to the break of the welding circuit. The closing contacts 8-10 of the intermediate switch 5 are included in the control circuit of the thyristor rectifier 2, the relay 11 of the coil 12 turn-on of the main switch 13. The contact 14, which is closed with delay when the time relay 11 is turned off, is connected to the coil 12 self-feeding circuit switch 13.

The role of the inductive delay element 16 in the intermediate switch 5 can be performed either on the coil side of the voltage winding 4, made of copper, or copper rings, which are additionally installed.

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The device works as follows.

In the initial state, in the presence of a network voltage at the system input, the main switch 13 is disconnected; there is a safe duty voltage from source 3 on the open welding electrodes. Time relay 11 is ready for circuit operation: phase B, terminals ab, phase C is its contact open . The intermediate switch 5 is disconnected, its contacts 8-10 are open. When the electrode touches the product, the winding 4 of the voltage of the switch 5 receives power from the source 3 via the "+ source 3, diode 6 isolation, welding circuit, current winding 7," - source 3. The switch 5 turns on and closes its contacts 8-10. Here, the main switch 13 is turned on and the welding rectifier is connected to the network. The thyristors in the fuser 2 are opened by pin 8 and the rectifier voltage enters the welding circuit. Receiving power at cd terminals, time relay 11 closes its contact 14.

With the start of welding, the 6-discharge diode closes, since the potential of the positive pole of source 3 is less than the potential of the positive pole of rectifier 2. The voltage 4 winding of switch 5 is turned off, while the latter is kept in the on state by welding current passing through the current winding 7. Coil 12 of the main switch 13 switches to self-feeding. At the end of the welding of the current, the winding 7 is de-energized, the intermediate switch 5 is turned off, its contacts 8-10 open, the voltage from the output of the rectifier 2 disappears as the thyristors close. Contact 9 of the intermediate switch 5 opens the circuit of the time relay 11, which starts counting the time. The isolation diode 6 opens, a safe voltage from source 3 is established at the welding electrodes. In case of resuming the welding, before the expiration of the relay 11 time setting, the intermediate switch 5 is turned on again by the voltage winding 4 and the operating voltage is restored at the electrodes. The countdown is terminated. Short non-current pauses, not exceeding 0.5 s according to the safety condition, are damped by the inductive delay element 16 of the intermediate switch 5, without causing the latter to switch off.

If the welding does not resume within the set time relay 11. The contact 14 is open, the coil 12 is de-energized and the main switch 13 is turned off, removing power from the welding rectifier. If welding is required, the process is repeated.

Compared with the known device, the presence of the isolation diode allows the intermediate voltage switch winding to be used only at the moment of ignition of the welding arc, which makes it possible to change the calculated winding ratios to reduce the response time and thereby increase the speed of the mouth, thereby increasing the speed of the device.

The use of a current winding in hold mode increases the reliability of the device over the entire range of welding currents. The inclusion of the current winding of the intermediate switch in the break of the welding circuit simplifies the design of the device with the exception of an additional current relay. The use of a time relay in conjunction with the use of thyristors makes it possible to eliminate frequent switching off and switching on of the welding rectifier, ensuring the removal of dangerous voltage from the electrode during welding pauses. An inductive delay element in an intermediate switch delays the voltage reduction at the electrodes during short pinless pauses, stabilizing the welding process.

Claims (1)

Invention Formula A device for switching on a welding transmitter containing a source of safe voltage of direct current, a main switch whose contacts are included in the power supply circuit of the welding rectifier, an intermediate switch with two windings and a closing contact, a disconnect diode element and a delay element differing from that that, in order to improve speed and reliability in operation, to eliminate frequent disconnections and switching on of the welding rectifier from the network, it is equipped with a time relay, and the welding relay has a thyristor m, one of the intermediate switch windings is made in the form of a voltage winding, and the other is in the form of a current winding, and the intermediate switch is provided with second and third closing contacts, while the beginning of the voltage winding and the end of the current winding of the intermediate switch are connected to the negative pole of the welding electrode the end of the voltage winding is connected to the negative pole of the safe voltage source, the current winding is connected in series to the welding circuit, the positive pole of the safe source the voltage through the isolation diode is connected to the positive pole of the welding rectifier, while a time relay is connected to the control circuit of the main switch, the second closing contact of the intermediate switch is inserted into the power supply circuit, and its third closing contact is connected to the welding rectifier control circuit , 5 wherein the delay element is inductive and is introduced into the intermediate switch. 0 ABC 0 & 0 73 AT + - # - 16 3cW 7GV7i h Y