SU1590253A1 - Source of power supply of arc with programmable low-frequency modulation of h.f.welding current - Google Patents

Abstract

The invention relates to a power source for welding, preferably with programmable low-frequency modulation of high-frequency welding current, and m. Used in non-consumable electrode welding in shielding gases. The purpose of the invention is to increase the productivity and quality of welding by facilitating regulation and increasing its accuracy. The source contains an output power control unit, a welding current sensor, a cycle driver, setters for the rise and fall currents of the pulses, the amplitudes of the current pulses, the amplitudes of the pause current, error indicators of the amplitudes of the current pulses and the pause current. When the source is operating, the cycle former generates the driving pulses. The unit for the rise and fall rates of the pulse current generates a linearly varying voltage. The current pulse amplitude adjuster summarizes the output signal of the pulse rise and fall speed master with the reference signal. In the setter of the amplitude of the pause current, the resulting signal is re-summed with the new reference signal. The resulting signal is compared with that obtained from the current sensor. The resulting signal, through the control circuits, controls the output power control unit. Error indicators compare current and reference current values. The deviation of the effective values from the given values is induced. 1 hp f-ly, 2 ill.

Description

The invention relates to power sources, mainly to welding power sources, and can be used as a power source for a welding arc, as well as a power source for an arc with modulated welding current.

The purpose of the invention is to increase the productivity and quality of welding by facilitating adjustment and increasing its accuracy at the arc power source by independently controlling all parameters of the welding current: pulse amplitudes and current flow, welding current time parameters, pulse current rise and fall rates.

FIG. 1 is a functional diagram of the arc power source; in fig. 2 - time diagrams of voltages on the circuit elements and welding current.

The device contains an output power control unit 1, a current sensor 2, an error amplifier 3, a control signal generation unit 4, a cycle driver 5, a pulse rise and fall rate current setting unit 6, a pulse amplitude setting unit 7. current pulses d, amplitude setting device 8

ate u o you ate

pause current indicator 9 error amplitude current pulses and indicator 10 pause current. The output power control unit 1 is connected to the input of current sensor 2, the output of which is connected to the first input of the error amplifier 3 connected by the output through the control signal generation unit 4 to the control input of the output power control unit 1, cycle driver 5, output connected to the setpoint input 6 of the speed of rise and fall of the pulse current, the output of which is connected to the input of the setpoint generator 7 of the current pulse amplitude, which is connected to the input of the setting unit 8 of the pause current connected to the output side of the second at the input of the amplifier 3 mismatches.

The indicator 9 for the error amplitude of the current pulses is connected in parallel with the setting device 6 for the speed of rise and fall of the current for the pulses, and the indicator 10 for the error for the current of the pause current is connected to the outputs of the generator 5 of the cycle and the setting device 8 for the pause current amplitude. The power source of the arc works as follows.

Before starting work, set technological napaMeTpt i; in the shaper 5 — the values of the duration of the driving pulses and the pause; in the setting units 6–8 — the rate of rise and fall of the current of the pulses, the amplitude of the current pulses, and the current of the pause. At the output of the former 5, a voltage UbSfig is generated. 2), which, arriving at the setpoint adjuster 6 of the rates of accumulation and decrease in the current of the pulses, transforms into a linearly varying first increasing and then / decreasing voltage Ue. This voltage is summed in the setter 7 for the amplitude of current pulses with the reference voltage of opposite polarity, and the total voltage for the moment of current pause is summed again in the setting unit 8 for the amplitude of the current for the pause with the reference voltage exhibited in the setting unit 8 for the current amplitude .

The resultant voltage Us is applied to the amplifier 3 mismatches. In the modulation mode, during which a pause current additionally flows through the arc during the action of a welding current pulse, the output signal of the setting unit 7 of the amplitude of current pulses Uy with a reference voltage is constant in the setting unit 8 of the pause current amplitude, i.e. for both the angular momentum and the pause, a signal is generated (Fig. 2). The signal received from the output of the setpoint 8 of the pause current amplitude is compared with the resultant signal obtained from the current sensor 2 by the amplifier 3 according to the resultant signal unit 4

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the formation of the control signal controls the operation of the output power control unit 1, the output of which receives a given welding current 1cv. Fig. 2 in the diagram shows the welding current curves of 1cv for the pulse-width adjustment of the welding current.

In the case of high rates of increase in the current of the pulses, the counter of the indicator 9 for the error amplitude of the current pulses is zeroed by the signal of the comparator entering it during each period of the current pulse and cannot count more than one pulse. As a result, a certain potential is displayed at the output of the indicator, which is output to the source display panel. At low speeds of current growth of pulses, zeroing pulses cease to flow to the pulse counter, which at the same time displays its state on the source display panel.

The pause current error indicator 10 operates similarly to the current pulse amplitude error indicator 9. the formation of the reference voltage of the comparator is performed by summing the unregulated voltage and the pause settings. When working with the proposed arc power source with programmable low-frequency modulation of the high-frequency welding current, the welder-operator does not need an instrument to measure the parameters of the modulated welding current. All 5 parameters of the low-frequency modulation can be set. And read on the switch scales.

In the developed scheme, it is also provided that the switch of the set point 6 allows the welder to set very small speeds for the increase of the pulse current. In this case, the amplitude of the low-frequency current pulses may not reach the value given by setpoint bm 7. This leads to the fact that the amplitude of current pulses, read on the scale of setpoint switch 7, does not coincide with the actual one. To indicate such a mode of operation, the indicator has an amplitude error with a light source (Fig. 1). To extinguish the LED, the welder-operator must increase the setpoint of the rate of rise of the pulse current in the setpoint 6 or increase the duration of the driving pulse in the shaper 5 cycles-55. After performing the specified switchings with the LED off, the mode parameters read are actual.

Modes of operation are possible with low set pulse current decay rates. This leads to the fact that in any phase of the pause, specified by the shaper 5 of the cycle, the arc current is determined only by the current of the negative pulse front. In this case, the pause current read on the scale of the setpoint switch 8 is not reliable. To indicate such a mode of operation, the pause tox error indicator 10 (Fig. 1) is used. To extinguish the LED indicator of the 10th operator, the operator must increase the speed setting of the pulse current decrease in the setting unit 6 or increase the duration of the master pause in the driver 5 of the cycle, or increase the pause current setting. After the indicated deistvings are completed, when the LED of the indicator 10 goes out, the parameters of the operation mode read from the scales of blocks 5–8 coincide with the actual ones.

Claims (2)

The arc power source with programmable low-frequency modulation of high-frequency welding current provides simple, accurate and operational control of the welding process with a non-consumable electrode in shielding gases. Claim 1. Arc power source with programmable low-frequency modulation of high-frequency welding current, containing output power control unit, output serially connected to the input of a current sensor whose output is connected to the first input of the error amplifier, connected via an output unit of a control signal to the control output of the output power control unit, a driver of the cycle, output connected to the input of the speed limiter the rise and fall of the pulse current, the setting devices of the amplitude of the current pulses, the pause current, characterized in that, in order to improve the accuracy of setting the parameters and facilitate adjustment Exit velocity setpoint rise and fall times of the current pulses is connected to input setpoint current pulse amplitude, whose output is connected to an input of the pause setpoint current output connected to the second input of the error amplifier. 2. A power source according to claim 1, characterized in that error amplitude indicators of current pulses and pause current are inputted thereto, the pulse amplitude error indicator is connected in parallel to the pulse current rise and fall rate adjuster, and the pause current error indicator is connected to the loop generator outputs and unit current pause. Network 1 Us igg,