SU1195311A1 - Apparatus for testing power sources of welding units - Google Patents

Description

The invention relates to electrical measuring equipment and can be used to test powerful sources of direct current power.

The purpose of the invention is to increase the reliability of the test results by obtaining smooth current-voltage characteristics of the test object and reducing the energy intensity of the tests due to the use of energy recovery into the network.

Fig. 1 shows a block diagram of a device for testing welding power sources; Fig. 2a shows the volt-ampere characteristic of the test power source of welding machines; in fig. 26 is a graph of the variation of the advance angle (inversion depending on the angular velocity of the setpoint (the speed of movement of the slider of the resistor); FIG. 3 is a schematic diagram of the thyristor control unit and the slave inverter.

The device for testing the power supply source 1 comprises a current control unit 2, a slave inverter 3, a thyristor control unit 4, a driver unit 5, a current sensor 6, a plotter 7, a DC power supply 8, first 9 and second 10 AC power sources, terminals 11 to connect the power supply, output terminals 2, input terminals 13, control current regulator 14, first 15, second 16 and third 17 thyristor control blocks, self-reset interlock contact 18, dual three-phase transformer 19, reactor 20, smoothing choke 21, six thyristors 22-27, a drive mechanism 28, a variable resistor 29, a high-resistance resistor 30, a blocking contact 31, a step finder 32, a stepper finder 33 detour, and a hague searcher movable contact 34, and the output terminals 12 are connected to the first output of block 2 current control, the second output of which is connected to the first input of the master unit 5 through the first AC power source, the second, the input of the master unit 5 is connected to the positive output of the DC power source 8, the negative end of which By connecting the first input of the control unit tiris11

tori, the first output of the master unit 5 is connected to the first input of the current control unit 2, the second and third outputs, respectively, to the second and third outputs of the thyristor control unit 4, the fourth input of which is connected to terminals 11 for connecting the power supply network, and the first, second and third outputs respectively to the first, second and third inputs of the slave inverter 3, the output of which is connected to terminals 11 for connecting the power supply network, the positive output of the fourth input - to the first input of the voltage input of the plotter 7 and the negative pin to the second pin of the voltage input of the plotter 7 and the negative input pin

terminals 13, the first output of the voltage input of the plotter 7 is connected to the positive input voltage of the input terminals 13 through the current sensor 5, the outputs of which are connected

To the current input of the plotter 7, the power inputs of which are connected to the outputs of the second AC power source.

The device operates as follows.

When supplying a three-phase supply voltage mi, UI and voltages of P. i., And to (i (Fig. 1, the device starts operation.

When receiving power, the test power source 1 generates direct current electrical energy. The installation is thus prepared for the process.

converting a constant voltage into an alternating inversion process carried out by the slave inverter 3 and then returning electrical energy to the supply network.

With the aid of a drive mechanism 28, a slider of a variable resistor 29 regulating a constant voltage Uj is set in motion.

supplied to thyristor control units 15-17. At the same time, a variable voltage is applied to these blocks, taking into account the sequence of alternation of fa. For example, the block

15, alternating voltage Uft is applied to block 16 and its voltage to block 17 (JCB G-P1 15-17 of thyristor control produces 6 pulses.

shifted by 60 ° in phase. The generated pulses are applied to the controlled electrodes of the thyristors 22-27 (see fig. 3) according to the vector diagram.

The pulse and U (, is supplied to the control electrode of the thyristor 22, and the pulse UujjHa control electrode of the thyristor 25, pulse Itd, to the control elec; the circuit of the thyristor 23, pulse and c 52 of the control electrode of the thyristor 26, pulse itc, is the control electrode of the thyristor 24, and the pulse Lcc - on the control electrode of the thyristor 27.

By varying the value of the control DC voltage AND, using a variable resistor 29 (see FIG. 1), the inversion angle of the slave inverter 3 is controlled, thereby regulating the electrical power supplied to the supply network.

One turn of the slider of the resistor 29 corresponds to removing the current-voltage characteristics of the test item for control current ((Fig.2a) at the end of the turn the slider of the resistor 29 passes the insulated part and the control circuit of the blocks 15-17 through the resistor 29 is de-energized.

At this moment, the blocking contact 31 is turned on and the control current passes through the high-resistance resistor 30, which corresponds to the transition of the test power supply 1 to practically idle mode. Simultaneously, the self-return contact 18 is turned on by means of the drive mechanism 28 of FIG. 1, alternating voltage U falls into the circuit of the winding 33 of the stepping finder and the moving contact 34 of the stepping finder is transferred to the subsequent position corresponding to the control current ig of the tested product.

Thereby, the current-voltage characteristics are monitored for the control current (see Fig. 2a). In the same way, the current-voltage characteristics of the test product are removed at different control currents and a family of current-voltage characteristics of the tested power source of welding machines is obtained. The blocking contact 31 is turned on by means of a drive mechanism 28 at the end of the first volt-ampere removal cycle, at the transition characteristics, the test article is at idle and remains on until the end of the full cycle of the removal of the current-voltage characteristics family.

The operation of the setting device for changing the inversion angle according to the sawtooth law is explained by the time diagram,

given in FIG. 26 (for simplicity, the plot of the inversion angle versus time / ± (t) is given in the diagram.

15 start of work, i.e. when

i Oh, the inversion angle Ro is the inverter supplied by the power supply network, respectively, the generated constant voltage UQ. the power source 1 to be tested (see fig.1) is equal to the idling voltage U x (see Fig. 2a). In the time interval i, -tp (see Fig.26, the inversion angle takes the value from and about

TO c, kc. Accordingly, the load current Jj varies from 3j O to Jj L mahe (see Fig. 2a). Subsequently, after the first cycle of current-voltage characteristics is removed for current, the angle

inversion takes on

from f D ° / "axio" corresponds to the period of time (fig.2b), at which the slider of the variable resistor 29 passes

the isolated part, i.e. By this time, the resistor circuit 29 is de-energized and the control current of the thyristor control units 15I7 passes through a high-resistance resistor 30. The test power supply 1 of the power supply passes practically into idle mode. Subsequently, the cycle is repeated. Fig. 2a shows five cycles of current-voltage characteristics of the welding power source under test.

P. CUGI.

The proposed device provides a family of uninterrupted current-voltage characteristics of the tested power sources of welding machines, at the same time saving electrical energy by recuperation, which

allows to increase the reliability of the test results while reducing the cost of electrical energy for their implementation.

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Claims (1)

^) DEVICE FOR TESTING POWER SUPPLIES OF WELDING MACHINES, containing terminals for connecting the power supply network, output and input terminals and a current control unit, 'characterized in that, in order to increase the reliability of the test results and reduce their energy consumption, a slave inverter, unit is introduced into it thyristor control, master unit, current sensor, plotter, DC power source, first AC power source, second AC power source, the output terminals being connected to the output the first output of the current control unit, the second output of which is connected to the first input of the driver unit through the first AC power source, the second input of the driver unit is connected to the positive terminal of the DC power source, the negative terminal of which is connected to the first input of the thyristor control unit, the first output of the driver unit is connected to the first input of the current control unit, the second and third outputs are respectively to the second and third inputs of the thyristor control unit, the fourth input of which о is connected to the terminals for connecting the power supply, and the first, second and third outputs, respectively, to the first, second and third inputs of the slave inverter, the output of which is connected to the terminals for connecting the power supply, the positive output of the fourth input is to the first output of the plotter voltage input, and the negative terminal - to the second terminal of the voltage input of the plotter and the negative terminal of the input terminals, the first terminal of the voltage input from © sl of the plotter is connected to the positive terminal of the input terminals through the sensors to the current, the output terminals of which are connected to the current input of the plotter, the Power leads of which are connected to the terminals of the second AC power source.