SU1465833A1 - Device for testing insulation of cable-type articles - Google Patents

Abstract

This invention relates to the field of electrical engineering. The purpose of the invention is to expand the scope and increase the reliability of the control. Phase regulator 2 generates control pulses applied to thyristors 6.7, Capacitor 5 discharges to the primary winding of high-voltage transformer 8, on the secondary winding of which a high-voltage pulse is formed that goes to remote electrode 10 and then to test from the component. With good cable insulation. runni me f f I - “7; 4 nC | ;, H j MKJ 11 I u l the constant voltage across the non-inverting input of the comparator is less than the amplitude of the pulses at its inverting input. In this case, the output of the comparator 20 will be a logical zero voltage. When there is a breakdown in the insulation of the cable, the pulse amplitude at the inverting input decreases, and the voltage of the logic unit appears at the output of the comparator 20. The introduction of a high-voltage divider 9, amplitude detector 11, amplifier 12, single-shot 14, 18, trigger 15 into the device AND-NOT 16, the counter 17, the HE 19 element, the comparator 20 made it possible to increase the reliability of the control by determining the breakdown by decreasing the amplitude of the pulses over several periods of the test voltage. Stays are provided by monitoring cable products that have an outer shield of non-metallic materials or a wet surface. 2 il, 1. nni me f f I; 4 iH | ;, J 11 I u (L with SL 00 00 00

Description

The invention relates to electrical engineering and can be used to test the insulation of cable products directly on the insulating processing lines.

The purpose of the invention is to expand the scope of application by controlling cable products with a screen of non-metallic materials or a wet surface and testing the accuracy of the control.

Fig. 1 is a schematic diagram of the device; in fig. 2 - test voltage pulse shape,

The device contains a power transformer 1, one of the secondary windings of which is connected to the input of the phase regulator 2, which has an output transformer 3 at the output and the other secondary winding of the power transformer 1 is connected to a series-connected choke 4 and a capacitor 5 connected to a series-connected thyristor switch, consisting of thyristors 6 and 7-, and the primary winding of a high-voltage pulse-type transformer 8, having a feedback winding connected to phase regulator 2, and the secondary the winding, the high-potential output of which is connected to the input of the high-voltage divider 9 and through the high-voltage electrode 10 to the test object, the core of which is connected to the common bus of the device; with the input of the amplitude detector 11, the output of which is connected to the input of the coupling device 12, which has a measuring device 13 at the output, a one-shot 14, the counting input of which is connected to the winding isolating transformer 3, the direct output of the one-shot 14 is connected to the counting input of the trigger 15, and the inverse output is connected to the first input of the AND-16 element, the second input of which is connected to the forward output of the trigger 15, the output of the element 16 is connected to the counting input of the counter 17 , the output of which is connected to the counting input of the second one-shot. 18, and the zero reset input of the counter 17 is connected to the output of the HE element 19,

the input of which is connected to the zeroing input of the trigger 15 and the output of the comparator 20, the inverting input of which is connected to the output of the high-voltage divider 9, and non-inverting - via potentiometer 21 with the output of the amplifier 1 2 "

The device works as follows.

When mains voltage is applied to the primary winding of the power transformer 1, the voltage of the required value from the secondary winding of the transformer 1 is fed to the phase regulator 2, which produces control pulses supplied through the separation transformer 3 to the control electrodes of the thyristor switch, consisting of thyristors 6 and 7, opening it at a certain moment relative to the voltage phase of the capacitor 5, which is connected via choke 4 to the other secondary winding of the power transformer.

Depending on the position of the setting body (not shown in the diagram) of the phase regulator, the time of opening the thyristor switch is controlled from 90

up to 160 degrees, in the positive half-period of the voltage across the capacitor 5 and from 270 to 340 degrees, in the negative. When opening the key, the capacitor 5 is discharged to the primary winding of the pulsed air transformer 8, as a result, a damping pulse appears in the windings of the transformer, the shape of which is shown in Fig. 2, C the high-voltage winding

transformer 8 high voltage pulses are supplied to the high voltage divider 9 and through the external electrode 10 to the insulation of the test cable, the conductor of which is connected to the common bus of the device and the low potential output of the high voltage winding of the transformer 8. At the same time, low voltage pulses from the return winding The signals come to the phase regulator where the stabilization scheme is used; 11 and the amplitudes of the pulses of the test voltage. From the output of the high-voltage divider 9, the pulses go to the amplitude detail Ktorov I1, whose output is connected to the input of amplifier 12

The constant charge of the diode detector is chosen from the condition

IA65833

SapSftq.,

where f is the oscillation frequency of the damped pulse,

and the constant bit satisfies the condition

ar yes -f- where C

J

- detector capacity; R, is the input impedance of amplifier 12;

F is the frequency of the probe pulses. From the output of amplifier 12, a constant voltage, proportional to aNmHHTy- of the test voltage pulse, is applied to a measuring instrument, the scale of which is calibrated in kilovolts.

Simultaneously from the output of the amplifier 12, a constant voltage is applied through potentiometer 21 to the non-sizing input of the comparator 20, and to the inverted-voltage transformer 8;

Tc 1 / F is the time period of the control pulses.

The front of the pulse from the direct input of the one-shot 14 sets the trigger 15 to a single state, overwriting the single

10 state of the information input. At the same time, the pulse from the inverse output of the one-shot 14 prohibits a change in the input state of the element AND-NOT 16, if during the pulse time

15 output of one-shot 14 by wil zero-level pulse and output of comparator 20, which corresponds to the case when the test isolation does not break down, then a zero-level 20 pulse sets trigger 15 to state O. In addition, zero

the pulse of the comparator 20, inverted by the element HE 19, resets the counter 17, If in time

tiring input of comparator 20 - impulse s, /

l., oh .... „..„ ,. ™. pulse output one-shot 14

sy from the output of high-voltage divider 9,

The magnitude of the DC voltage in the absence of breakdowns in the insulation of the cable under test is set to a potentiometer 21 such that it is less than the maximum amplitude of the damped pulse arriving at the inverter input of the comparator. In this case, at the moment of arrival of the pulse at the input of the comparator 20, a zero pulse is formed .

When there is a breakdown in the isolation of the test cable, the pulse amplitude decreases sharply, and the constant voltage at the non-inverting input of the comparator due to the inertia of the amplitude detector H for some time is greater than the pulse amplitude (at least for several tens of periods), resulting in a comparator the voltage is kept equal to 1; At the same time, the leading edge of the control pulses coming from the spin output of the comparator 20 was not a zero-level pulse; A vibrator 14 at the output of the element I6 appears level O and a unit is added to the contents of the counter 17.

After filling in the counter the number causing the setting of the output of the counter connected to the input of the one-shot of the torus 18 to one, the latter is triggered, the relay coil 22 and the counter 23 winding are fed; the relay with its contacts includes an external alarm and, if necessary.

40 turns off the process line drives; the counter is added to the existing number of breakdowns by one more.

Due to the fact that the breakdown is determined by several pulses, which have a reduced duration for several periods of time, the noise immunity is increased, ... false alarms are detected when the device is switched on to the network and in some Invention Formula

In the case of the transformer 3's primary winding in 50 other cases, the counting input of the one-shot 14, the output of the one-shot 14 produces pulses of duration f that satisfy the condition

j.ma, 9 Tc,

where i d, (, x is the time between the arrival of the control pulse and the nm pulse at the output, there is a device for testing the insulation of 55 cable products containing a power transformer, a phase regulator, - "choke, nepBbdt capacitor, first and second thyristors, pulsed high-voltage external transformer

covoltage transformer 8;

Tc 1 / F is the time period of the control pulses.

The front of the pulse from the direct input of the one-shot 14 sets the trigger 15 to a single state, overwriting the single

0 state of the information input. At the same time, the pulse from the inverse output of the one-shot 14 prohibits a change in the input state of the element AND-NOT 16, if during the pulse time

5 the output of the one-shot 14 by wil impulse of the zero level and the output of the comparator 20, which corresponds to the case when the breakdown of the test isolation does not occur, the impulse of the zero level sets the trigger 15 to the state O. In addition, zero

at the output of the comparator 20 there was no zero-level pulse, on the falling edge of the pulse of the one-shot 14 at the output of element I6 a level O appears and one is added to the contents of the counter 17.

After filling in the counter the number of the installation causing the output of the counter connected to the input of the one-shot of the torus 18 to one, the latter is triggered, the relay coil 22 is powered and the counter 23 is coiled; the relay with its contacts includes an external alarm and, if necessary.

40 turns off the process line drives; the counter is added to the existing number of breakdowns one more

Due to the fact that the breakdown is determined by several pulses, which have a reduced duration for several periods of time, the noise immunity is increased, ... false alarms are detected when the device is switched on to the network and in some Invention Formula

ry other cases

50 ry other cases

A device for testing the insulation of 55 cable products, containing a power transformer, a phase regulator, a choke, a nepBbdt capacitor, a first and second thyristor, a high-voltage pulse transformer, an external

f1 / e.g

Claims (1)

Claim Device for testing insulation of cable products containing a power transformer, phase regulator, - < inductor, first capacitor, first and second thyristors, switching high-voltage transformer, remote with The electrode, the primary winding of the power transformer is connected to the M pole of the network, and its first secondary winding is connected to the first and second inputs of the phase regulator, the first output of which is connected to the cathode of the first Thyristor and the first output of the primary winding of the high voltage transformer, the second and third outputs of the phase regulator are connected to the control electrodes, respectively, of the first and second thyristors, and the fourth output of the phase regulator is connected to the first output of the capacitor and the first output 15 of the second secondary winding of the power transformer ora, the second output of which is connected to the first output of the inductor, the first output of the secondary winding of the high-voltage transformer is connected to a remote electrode connected to the control object, the core of which is connected to the device common bus, characterized in that, in order to expand the scope and increase the reliability of control, a high-voltage divider, an amplitude detector, a resistor, a comparator, an element NOT, the first and second one-shots, a trigger, an element NAND, a counter, an amplifier are introduced into it, we accept the second output of the capacitor ene with second terminals of the choke and rervichnoy high voltage transformer winding, a cathode and an anode of the second thyristor are respectively connected to the anode and the cathode of the first thyristor, the second terminal of the high voltage transformer secondary winding is connected to the common bus device remote. the electrode is connected to the first output of the high-voltage divider, the second output of which is connected to the inverting input of the comparator and the input of the amplitude detector, the output of which is connected to the input of the amplifier, the output of which is connected to the first output of the measuring device and the first output of the resistor, the second output of which is connected to the non-inverting input of the comparator, the output of which is connected to the trigger zeroing input and through the element is NOT connected to the counter zeroing input, the fifth phase regulator output is connected to the counting input of the first a vibrator whose inverse output is connected to the first output of the NAND element, and the direct output is connected to the counting input of the trigger, the output of which is connected to the second input of the NAND element, the output of which is connected to the counting input of the counter, the output of which is connected to the counting input of the second one-shot , the third terminal of the high voltage divider, the second terminal of the measuring device, the third terminal of the resistor are connected to a common bus of the device.