SU1232413A1 - Arrangement for welding apparatus - Google Patents

Description

one

The invention relates to the field of welding, namely to welding equipment, and can be used in welding machines producing welding in a protective gas environment.

The aim of the invention is to improve reliability indicators by protecting the device from short circuits in the motor winding circuit and the gas valve, protecting the device from simultaneous switching of the thyristors of the power supply control and dynamic braking, reduced power consumption by connecting the motor winding and the gas valve to the power source only during the supply of protective gas to the welding zone.

FIG. 1 shows a block diagram of a control unit for a semiautomatic arc welding machine; in Fig.2 is a timing diagram of the blocks of the proposed device.

The device comprises a switch-on unit 1 (control unit), which is connected to the cycle unit 2 and the engine control unit comparison circuit 3. On the front panel of the control panel 1 there are buttons set to start gas valve start, engine start, initial setting and engine speed setting potentiometer. The cycle block 2 is connected to the matching circuits 4 and 5, as well as to the modulation unit 6 and the matching circuit 7. The motor excitation winding 8 is connected via a diode to the collector of transistor switch 9. Static trigger 10 is connected to output circuits 4.5 and 7, and the input is connected to transistor 11. The initial setup input of S-trigger 10 is connected to the power supply Ej and button Initial mouth

novka on the remote 1, and the inputs of the 1st

K-flip-flop 10 is connected to the volume / i; e of the power source Efi.

The armature of the engine 12 is connected via a correction device 13 to the comparison circuit 3. A signal to turn on the welding power supply source 14 is supplied from the coincidence circuit 7. The gas valve 15 is shunted by a diode 16, and through diode 17 it is connected to the collector of switch 9 and through diode 18 - parallel to the winding 8 of engine 12.

The transistor switch 9 base is connected to the circuit 4 matches, and the emitter - to the base of the transistor 11, the collection

five

0

5 Q

five

0

five

0

32

the torus of which is connected to the counting input of the static trigger 10. The output transistor 19 through the R and V circuits is connected to the cathode of the thyristor 20. In addition, the device contains an amplifier 21 in the motor control circuit and the feed mechanism 22 of the electrode wire.

FIG. 2 - voltage on the engine bark;

Upg, Urj is the voltage across the field winding and the gas valve, respectively;

BC1

Uj., - voltages from the outputs of the cycle block; Ug is the voltage from the output of the modulation unit;

and - the voltage from the output of the transistor 9; (h - gas purge delay; time dynamically

braking; - zone protection time

gas welding.

The device works as follows.

When the Start button on the control panel is pressed, the potential signal is fed to the 2-cycle unit and the setpoint to the input of the circuit 3 of the engine control unit is simultaneously set. At the signal of the Start button, the cycle block accumulates potential signals

u, q, .i. ,,. івц4 и.5 (). The signal goes to the input of circuit 4, matches, V to the input of circuit 5, matches, to the input of modulation unit 6, Uf, 4 3 inputs of circuit 7, Ug ,. - to the input of the thyristor 20 of the dynamic braking. According to the signal and, the modulation unit 6 modifies the output

a package of pulses of constant duty cycle, which provides the nominal voltage on the motor excitation winding 8. The signal and the presence of signals at other inputs of the circuit 5 from coincidence of transistor 19 and trigger 10 supply voltage to the motor 12 and, if there is a voltage on the excitation winding 8, feed mechanism 22 to feed the wire to the welding zone. The speed feedback signal is fed through the correction device 13 to the input of the compared device 3. The signal U ,, circuit 7 coincides with

the presence of a signal from the trigger trigger 10 turns on the power source 14 for welding current through the coincidence circuit 7, the gas valve 15 operates according to the time diagrams similar to the winding 8. The diode 16 serves to protect the electronic components from overvoltages.

Diodes 17 and 18 are used for isolating the gas valve 15 and winding 8

excitation and provide separate 10 and on the gas valve 15. The frequency moruchny inclusion from the remote control 1 control.

Protection of the device against short circuits in the circuit of the excitation winding 8

or gas valve 15 provides - 15 Forcing a constant voltage to these

with the following.

The current through the transistor 9 increases, transistor 11 is turned on, and flip-flop 10 is triggered, removing the enable signal (low level) from the inputs of circuits 4.5 and 7, which causes the welding power supply source 14 to be turned off, the voltage from the motor core 12 and the closing of the transistor 9. The device is de-energized. After an emergency de-energization of the device (engine core, welding current source, field winding and gas valve) and to set the trigger 10 to the initial state, press the Initial Setup button on the control panel 1. Parallel operation of the field winding 8 and gas valve 15 is provided through transistor 9, operating in key mode.

Voltage modulation is carried out as follows. The set of constant-duty-cycle pulses, applied by modulation unit 6, via a signal U, arrives at a coincidence circuit 4 and in the presence of signals at other inputs (Fig. 2), through transistor 9, modulates the voltage on the excitation winding 8

The pulsation is chosen such that it provides current continuity with permissible pulses through the winding 8 and the gas valve 15 by means of a diode 16.

nodes at time (/ 2 improves dynamic braking (reduces braking time). The presence of a constant voltage in the time interval Tj 20 improves the activation of the gas valve 15 when the supply voltage is low.

Protection against simultaneous switching on and braking thyristors is provided as follows. When the Start button is turned off, the 2 Cycles block generates a signal arriving at the control electrode of the thyristor 20, and simultaneously a signal Ufji. Is received at the input of the coincidence circuit 5, which closes the switching-on thyristor. The transistor 19 opens and removes the enable signal from the input of the matching circuit 5 for a time

35

while thyristor is open 20.

G /

2

Claims (1)

ARC WELDING DEVICE, comprising an electrode wire feed motor connected to a control unit including a comparison circuit and an amplifier, a cycle unit, a gas valve electromagnet, a dynamic braking thyristor and a switching unit with switching elements and a start button, characterized in that, in order to increase reliability in operation and energy saving, a transistor switch, a transistor, a trigger, three matching circuits, a modulation unit, an RC chain, decoupling diodes and an output transistor are introduced into the device In this case, the collector of the transistor switch is connected via decoupling diodes to the winding of the electromagnet of the gas valve and the field winding of the electrode wire feed motor, the emitter of the transistor switch is connected to the base of the transistor, the collector of which is connected to the counting input of the trigger, and the emitter to the common point of the power source, input the trigger setup is connected to a power source and to the output of the initial installation of the power unit, the trigger output is connected to the first inputs of the matching circuits, the output of the first matching circuit is connected is connected to the base of the transistor switch, the second input is connected through the modulation unit to the first and the third to the second outputs of the cycle block, the third output of which is connected to the second input of the second matching circuit, the third input of which is connected to the collector of the output transistor, the fourth input to the output of the circuit comparison of the control unit of the electrode wire feed motor, and the output is connected to the input of the amplifier of this unit, the fourth output of the cycle block is connected to the second input of the third matching circuit, the output of which is connected to the input of the power source In addition, the cathode of the dynamic braking thyristor is connected through a cathode to the common point of the RC circuit, the other output of the capacitor of which is connected to the common point of the power source, and the output of the resistor to the base of the output transistor, the emitter of which is also connected to the common point of the power source. SU .1232413