SU1400817A1 - Apparatus for reducing the voltage of no-load running - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to devices for improving electrical safety during arc welding. The goal is to reduce energy consumption, increase reliability and noise immunity of the device. The device contains the main and backup switches, the control unit of the main switch, the standby protection unit and current and voltage sensors. In addition, the power supply unit and the installation scheme are introduced into the zero point of the backup timer into the standby unit. When the device is in standby mode, the backup block is disabled. It is powered only during the welding process. Since the complexity of the backup protection unit approaches the complexity of the main circuit, switching it off in standby mode leads to a reduction in energy consumption and an increase in the reliability of the device. 2 Il. (L

Description

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The invention relates to electrical engineering, in particular, to devices for improving electrical safety during arc welding, and can be used in protective disconnection devices, insulation control devices, etc.

The purpose of the invention is to reduce power consumption, increase the reliability and noise immunity of the device.

FIG. Figure 1 shows a block diagram of a device for reducing the no-load voltage; in fig. 2 is a block diagram of the backup protection unit.

The device contains the main switch I, the backup switch 2, the main switch control unit 3, the backup protection unit 4, voltage 5 and current sensors 6. Also shown is the power source 7 of the welding arc, the electrode holder 8, the welded metal structure 9, the network contacts 10 (FIG. one). The backup protection unit 4 comprises a power supply unit 11, a backup timer 12 and a timer setting circuit 13 to zero (Fig. 2).

The device works as follows.

In the initial state, when the welding circuit is open and the backup switch 2 is closed, a reduced voltage is formed at the input of the power supply 7 by appropriately affecting the control unit 3 on the main switch i (e.g., phase control using power thyristors). At the same time, at the output of voltage sensor 5 (transformer), the signal is very small; at the output of power supply unit 11, there is no voltage. The fact that there is no voltage on the circuit of the backup protection unit and predetermines the high immunity of the device, namely, the inadmissibility of false activation of the backup switch 2. When the electrode 8 is closed on the welded metal structure 9, the control unit 3 generates a start signal by means of the current sensor 6 switch 1, which connects power supply 7 to mains 10, and a full secondary voltage of power supply 7 appears in the welding circuit. A welder can energize and weld. When the main switch 1 is turned on, a voltage appears at the output of the sensor 5, which is connected to the input of the power supply box 11. At the output of the next voltage, the voltage necessary for the operation of unit 4 of the backup section occurs. When the output voltage of the power supply unit 11 appears, the installation circuit 13 generates a pulse that sets the backup timer 12 in the process of welding. The welding signals of the current sensor 6 arrive at the installation circuit 13, the output signals of the backup timer 12 are generated at its output, which is maintained in mode

welding in the state of "O. The signals of the current sensor b, acting on the control unit 3, maintain the main switch 1 in a closed state.

At the end of the welding signals disappear.

current sensor 6, the timer of the control unit 3 of the main switch 1 and the backup timer 12 begin counting the exposure time of the unloaded idle voltage. The time interval after which at the output of the timer of block 3 appears the signal for switching off the main switch 1 and switching the device to the reduced voltage generation mode (initial state) is several (5-10 ° / o) shorter than the time interval formed backup timer 12. Therefore, during normal operation of the device, the backup protection unit 4 does not affect the operation of the circuit. When the timer of the block 3 fails, the timer 12 of block 4 sends a signal to the backup switch 2. The block 4 of the backup protection and the backup switch 2 act similarly if there is any failure of the control block 3 or the main switch 1: when voltage appears at the output of the sensor 5

5 and the absence of a current sensor 6 signal, the switch 2 disconnects the power source 7 from the network 10.

Compared with the known device, the elimination of the need to keep the backup protection unit under idling during the idling reduces energy costs, increases the reliability and noise immunity of the device for reducing the idling voltage.

Claims (1)

Invention Formula A no-load voltage suppression device containing main and backup switches connected in series between the network and the power source of the welding arc, a control unit for the main switch, a backup protection unit with a backup timer, the output of which is connected to the control input of the backup coaxial switch, and a sensor voltage, connected in parallel to the input of the power source, and a current sensor, contactlessly included in the welding circuit, with the sensor outputs connected to the inputs of the control unit and the backup protection unit you are different that, in order to reduce energy consumption, increase reliability and noise immunity, the device is equipped with a power supply unit of the backup protection unit and an installation circuit in the “About backup timer, while the input of the unit the power supply of the backup protection unit is connected to the output of the voltage sensor, the input of the setup circuit to “About the backup timer is disjunctively connected to the output of the current sensor and the output of the power supply unit of the backup protection unit, and the output of the installation scheme in “About the backup timer is connected to the installation the backup timer input, and the voltage sensor is in the form of a transformer. For example 9 J From current sensor 6