Breakdown protection circuit for high-voltage and ultrahigh-voltage withstand voltage instrument

Abstract

The utility model discloses a high-voltage and ultrahigh-voltage withstand voltage instrument breakdown protection circuit which comprises a relay JK1, a relay JK2, a relay JK3, a relay JK4, a voltage regulator VR and a high-voltage transformer T. A primary winding of the high-voltage transformer T is connected in series between a first pin and a third pin of the voltage regulator VR. The lead between the VR3 pin of the voltage regulator and the primary winding of the high-voltage transformer T is sleeved with a mutual inductor B1, and the mutual inductor B1 is connected with a comparison circuit. The utility model relates to the technical field of breakdown protection of high-voltage and ultrahigh-voltage withstand voltage instruments. According to the utility model, through the arranged breakdown protection circuit for the high-voltage and ultrahigh-voltage withstand voltage instrument, when a sample is broken down or high-voltage arc discharge occurs, high voltage can be cut off stably and quickly, damage to machines or people is avoided, and the safety performance is high.

Description

Technical Field

[0001] The utility model relates to the technical field of breakdown protection of high-voltage and extra-high-voltage withstand voltage testers, specifically a breakdown protection circuit for high-voltage and extra-high-voltage withstand voltage testers. Background Art

[0002] High-voltage and extra-high-voltage withstand voltage testers are devices used to detect the insulation strength of various electrical equipment, electrical components, and insulating materials under high voltages. These devices are widely used in power systems, industrial and mining enterprises, scientific research departments, etc., and have the characteristics of small volume, light weight, compact structure, complete functions, strong versatility, and convenient use.

[0003] The basic working principle of a high-voltage and extra-high-voltage withstand voltage tester is as Figure 1 shown. For a conventional withstand voltage tester, starting and resetting are achieved by sending signals to the single-chip microcomputer through buttons S1 and S2. (When the start button S1 is pressed, the coil of relay JK1 is energized and attracted, and pins 4 and 6 are connected to send a start signal to the single-chip microcomputer, and the instrument starts. When the reset button S2 is pressed, the coil of relay JK2 is energized and attracted, and pins 4 and 6 are connected to send a high level to the single-chip microcomputer, and the instrument resets). The single-chip microcomputer controls the start and reset of the instrument. Under normal circumstances, there is no problem in use. However, in actual operation, due to the uncertainty of the quality of the measured sample, breakdown or high-voltage arcing may occur after applying high voltage. Due to the poor anti-interference performance of the single-chip microcomputer, the situation of the single-chip microcomputer getting out of control may occur, that is, the single-chip microcomputer is not controlled by the button and cannot quickly cut off the high voltage, which will cause damage to the machine or people.

[0004] Therefore, the utility model provides a breakdown protection circuit for a high-voltage and extra-high-voltage withstand voltage tester to solve the above problems. Content of the Utility Model

[0005] In view of the deficiencies of the prior art, the utility model provides a breakdown protection circuit for a high-voltage and extra-high-voltage withstand voltage tester, which solves the above problems.

[0006] To achieve the above objectives, the utility model is realized through the following technical solutions: A breakdown protection circuit for a high-voltage and extra-high-voltage withstand voltage tester, comprising:

[0007] Relay JK1, where the 1st pin and the 8th pin of the relay JK1 are connected to a 12V power supply, the 4th pin of the relay JK1 is grounded, the 6th pin of the relay JK1 is connected to the start terminal of an external MCU, and the 7th pin of the relay JK1 is connected to the ground after being connected in series with the start button S1;

[0008] Relay JK2, the signal of pin 1 of the relay JK2 is connected to pin 2 of the relay JK1, pin 4 of the relay JK2 is connected to the 5V power supply, pin 6 of the relay JK2 is connected to the reset terminal of the external MCU, pin 7 of the relay JK2 is grounded after being connected in series with the reset button S2, and pin 8 of the relay JK2 is connected to the 12V power supply;

[0009] Relay JK3, the signal of pin 1 of the relay JK3 is connected to the output terminal of the external MCU, the signal of pin 4 of the relay JK3 is connected to pin 1 of the relay JK2, the signals of pins 6 and 8 of the relay JK3 are connected to pin 3 of the relay JK2, and pin 7 of the relay JK3 is grounded;

[0010] Relay JK4, an alternating current of 220V is connected between pin 1 and pin 4 of the relay JK4, the signal of pin 7 of the relay JK4 is connected to pin 2 of the relay JK3, and pin 8 of the relay JK4 is connected to the 12V power supply;

[0011] Voltage regulator VR, the signal of pin 1 of the voltage regulator VR is connected to pin 6 of the relay JK4, and the signal of pin 2 of the voltage regulator VR is connected to pin 3 of the relay JK4;

[0012] High-voltage transformer T, the primary winding of the high-voltage transformer T is connected in series between pin 1 and pin 3 of the voltage regulator VR, and a current transformer B1 is sleeved on the wire between pin 3 of the voltage regulator VR and the primary winding of the high-voltage transformer T, and the current transformer B1 is connected to a comparison circuit.

[0013] Preferably, the comparison circuit includes resistors R1 - R16, zener diodes D3, D4, D6, D7, operational amplifiers OP1, OP2, OP3, OP4, capacitors C2, C4, C6, C8, C10, C12, comparator U1, triode Q1, and relay JK5.

[0014] Preferably, both ends of the resistor R1 are signal-connected to both ends of the mutual inductor B1. The 3rd pin of the operational amplifier OP1 is signal-connected to the B1-1 end of the resistor R1. The 2nd pin of the operational amplifier OP2 is connected to the 1st pin of the operational amplifier OP1 after being serially connected with the resistor R2. The 3rd pin of the operational amplifier OP2 is connected to the B1-2 end of the resistor R1 after being serially connected with the resistor R4. The 6th pin of the operational amplifier OP3 is signal-connected to the 1st pin of the operational amplifier OP2 after being serially connected with the resistor R5 and the voltage regulator diode D6. The 5th pin of the operational amplifier OP3 is signal-connected to the B1-2 end of the resistor R1 after being serially connected with the resistor R8 and the resistor R9. The 3rd pin of the operational amplifier OP4 is signal-connected to the 7th pin of the operational amplifier OP3 after being serially connected with the resistor R10.

[0015] Preferably, the 2nd pin of the comparator U1 is signal-connected to the 1st and 2nd pins of the operational amplifier OP4 after being serially connected with the resistor R11. The 1st pin of the comparator U1 is signal-connected to the base of the triode Q1 after being serially connected with the resistor R16.

[0016] Preferably, the 1st pin of the relay JK5 is signal-connected to the 4th pin of the relay JK3. The 3rd pin of the relay JK5 is signal-connected to the 6th pin of the relay JK3. The 4th pin of the relay JK5 is signal-connected to the emitter of the triode Q1. Advantages

[0017] The present utility model provides a breakdown protection circuit for a high-voltage and ultra-high-voltage withstand voltage tester. Compared with the prior art, it has the following advantages:

[0018] Through the provided breakdown protection circuit for the high-voltage and ultra-high-voltage withstand voltage tester, when the sample is broken down or there is a high-voltage arcing phenomenon, it can stably and quickly cut off the high voltage, avoiding damage to the machine or people, and having high safety performance. Description of the Drawings

[0019] Figure 1 It is the basic working principle circuit diagram of the existing high-voltage and ultra-high-voltage withstand voltage tester in the background art;

[0020] Figure 2 It is the circuit diagram of the improved high-voltage and ultra-high-voltage withstand voltage tester of the present utility model;

[0021] Figure 3 It is the circuit diagram of the comparison circuit of the present utility model. Detailed Embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0023] Please refer to Figure 2-3 , the breakdown protection circuit of the high-voltage and ultra-high-voltage withstand voltage tester, including:

[0024] Relay JK1, the 1st pin and the 8th pin of relay JK1 are connected to a 12V power supply, the 4th pin of relay JK1 is grounded, the 6th pin of relay JK1 is connected to the start terminal of the external MCU, and the 7th pin of relay JK1 is connected to the ground after being connected in series with the start button S1;

[0025] Relay JK2, the 1st pin signal of relay JK2 is connected to the 2nd pin of relay JK1, the 4th pin of relay JK2 is connected to a 5V power supply, the 6th pin of relay JK2 is connected to the reset terminal of the external MCU, the 7th pin of relay JK2 is connected to the ground after being connected in series with the reset button S2, and the 8th pin of relay JK2 is connected to a 12V power supply;

[0026] Relay JK3, the 1st pin signal of relay JK3 is connected to the output terminal of the external MCU, the 4th pin signal of relay JK3 is connected to the 1st pin of relay JK2, the 6th pin and the 8th pin signals of relay JK3 are connected to the 3rd pin of relay JK2, and the 7th pin of relay JK3 is grounded;

[0027] Relay JK4, there is a 220V alternating current connected between the 1st pin and the 4th pin of relay JK4, the 7th pin signal of relay JK4 is connected to the 2nd pin of relay JK3, and the 8th pin of relay JK4 is connected to a 12V power supply;

[0028] Voltage regulator VR, the 1st pin signal of voltage regulator VR is connected to the 6th pin of relay JK4, and the 2nd pin signal of voltage regulator VR is connected to the 3rd pin of relay JK4;

[0029] High-voltage transformer T, the primary winding of high-voltage transformer T is connected in series between the 1st pin and the 3rd pin of voltage regulator VR, and a current transformer B1 is sleeved on the wire between the 3rd pin of voltage regulator VR and the primary winding of high-voltage transformer T, and current transformer B1 is connected to a comparison circuit.

[0030] The comparison circuit includes resistors R1 - R16, zener diodes D3, D4, D6, D7, operational amplifiers OP1, OP2, OP3, OP4, capacitors C2, C4, C6, C8, C10, C12, comparator U1, triode Q1, and relay JK5.

[0031] The two ends of resistor R1 are signal - connected to the two ends of transformer B1. The 3 - pin of operational amplifier OP1 is signal - connected to the B1 - 1 end of resistor R1. The 2 - pin of operational amplifier OP2 is connected to the 1 - pin of operational amplifier OP1 after being in series with resistor R2. The 3 - pin of operational amplifier OP2 is connected to the B1 - 2 end of resistor R1 after being in series with resistor R4. The 6 - pin of operational amplifier OP3 is signal - connected to the 1 - pin of operational amplifier OP2 after being in series with resistor R5 and zener diode D6. The 5 - pin of operational amplifier OP3 is signal - connected to the B1 - 2 end of resistor R1 after being in series with resistor R8 and resistor R9. The 3 - pin of operational amplifier OP4 is signal - connected to the 7 - pin of operational amplifier OP3 after being in series with resistor R10.

[0032] The 2 - pin of comparator U1 is signal - connected to the 1 - pin and 2 - pin of operational amplifier OP4 after being in series with resistor R11. The 1 - pin of comparator U1 is signal - connected to the base of triode Q1 after being in series with resistor R16.

[0033] The 1 - pin of relay JK5 is signal - connected to the 4 - pin of relay JK3. The 3 - pin of relay JK5 is signal - connected to the 6 - pin of relay JK3. The 4 - pin of relay JK5 is signal - connected to the emitter of triode Q1.

[0034] In this embodiment, when the Figure 2 start button S1 is pressed, the coil of relay JK1 is energized and attracted, and its 4 - pin and 6 - pin are connected, giving a start signal to the external MCU (i.e., the single - chip microcomputer), and the instrument starts. When the reset button S2 is pressed, the coil of relay JK2 is energized and attracted, and its 4 - pin and 6 - pin are connected, giving a high level to the single - chip microcomputer, and the instrument is reset. When the test sample has an arc breakdown, a short - circuit current will be generated instantaneously, and the primary current of the high - voltage transformer T will be much larger than the maximum current during normal operation. When the primary current is greater than the maximum operating current, the current induced by transformer B1 passes through Figure 3 resistor R1 to form a voltage, which is amplified and detected by the operational amplifier and then sent to the 2 - pin of comparator U1. The 3 - pin of comparator U1 is the voltage corresponding to the preset maximum operating current. When the voltage at the 2 - pin of comparator U1 is greater than the voltage at the 3 - pin, the 1 - pin of comparator U1 outputs a low level, triode Q1 conducts, the coil of relay JK5 is energized and attracted, and the 1 - pin and 3 - pin of relay JK5 are connected. Points A and B are connected to Figure 2Pins 4 and 6 of relay JK3. When pins 1 and 3 of relay JK5 are connected, the coil of relay JK3 is energized and self-locked through its own contacts (pins 4 and 6 are connected), and pins 1 and 2 of relay JK3 are disconnected. Because pins 1 and 2 of relay JK3 are long closed, they are connected in series with the control line of MCU. After pins 1 and 5 are disconnected, relay JK4 does not work, and the input end of high-voltage transformer T loses power, and then effectively disconnects the high-voltage output to protect the safety of human and machine. When the machine is turned on for the second time after processing, press the start button S1, the coil of relay JK1 is energized and energized, pins 4 and 6 are connected, and the microcontroller is given a start signal. At the same time, pins 1 and 2 are disconnected, causing the coil of relay JK3 to lose power, pins 1 and 2 are closed, and the instrument resumes microcontroller control.

[0035] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Breakdown protection circuit for high voltage and extra-high voltage withstand voltage tester, characterized in that Including: Relay JK1, where the 1st pin and the 8th pin of the relay JK1 are connected to a 12V power supply, the 4th pin of the relay JK1 is grounded, the 6th pin of the relay JK1 is connected to the start terminal of an external MCU, and the 7th pin of the relay JK1 is grounded after being connected in series with a start button S1; Relay JK2, where the 1st pin signal of the relay JK2 is connected to the 2nd pin of the relay JK1, the 4th pin of the relay JK2 is connected to a 5V power supply, the 6th pin of the relay JK2 is connected to the reset terminal of an external MCU, the 7th pin of the relay JK2 is grounded after being connected in series with a reset button S2, and the 8th pin of the relay JK2 is connected to a 12V power supply; Relay JK3, where the 1st pin signal of the relay JK3 is connected to the output terminal of an external MCU, the 4th pin signal of the relay JK3 is connected to the 1st pin of the relay JK2, the 6th pin and the 8th pin signals of the relay JK3 are connected to the 3rd pin of the relay JK2, and the 7th pin of the relay JK3 is grounded; Relay JK4, where an alternating current of 220V is connected between the 1st pin and the 4th pin of the relay JK4, the 7th pin signal of the relay JK4 is connected to the 2nd pin of the relay JK3, and the 8th pin of the relay JK4 is connected to a 12V power supply; Voltage regulator VR, where the 1st pin signal of the voltage regulator VR is connected to the 6th pin of the relay JK4, and the 2nd pin signal of the voltage regulator VR is connected to the 3rd pin of the relay JK4; High-voltage transformer T, where the primary winding of the high-voltage transformer T is connected in series between the 1st pin and the 3rd pin of the voltage regulator VR, and a current transformer B1 is sleeved on the wire between the 3rd pin of the voltage regulator VR and the primary winding of the high-voltage transformer T, and the current transformer B1 is connected to a comparison circuit.

2. The breakdown protection circuit of the high voltage and ultra-high voltage withstand voltage tester according to claim 1, characterized in that: The comparison circuit includes resistors R1 - R16, zener diodes D3, D4, D6, D7, operational amplifiers OP1, OP2, OP3, OP4, capacitors C2, C4, C6, C8, C10, C12, comparator U1, triode Q1, and relay JK5.

3. The breakdown protection circuit of the high-voltage and ultra-high-voltage withstand voltage tester according to claim 2, wherein: Both ends of the resistor R1 are signal-connected to both ends of the current transformer B1. The 3rd pin of the operational amplifier OP1 is signal-connected to the B1-1 end of the resistor R1. The 2nd pin of the operational amplifier OP2 is connected to the 1st pin of the operational amplifier OP1 after being connected in series with the resistor R2. The 3rd pin of the operational amplifier OP2 is connected to the B1-2 end of the resistor R1 after being connected in series with the resistor R4. The 6th pin of the operational amplifier OP3 is signal-connected to the 1st pin of the operational amplifier OP2 after being connected in series with the resistor R5 and the zener diode D6. The 5th pin of the operational amplifier OP3 is signal-connected to the B1-2 end of the resistor R1 after being connected in series with the resistors R8 and R9. The 3rd pin of the operational amplifier OP4 is signal-connected to the 7th pin of the operational amplifier OP3 after being connected in series with the resistor R10.

4. The breakdown protection circuit of the high voltage and ultra-high voltage withstand voltage tester according to claim 3, characterized in that: The 2nd pin of the comparator U1 is connected to the 1st and 2nd pins of the operational amplifier OP4 after being serially connected with the resistor R11, and the 1st pin of the comparator U1 is connected to the base of the triode Q1 after being serially connected with the resistor R16.

5. The breakdown protection circuit of the high-voltage and ultra-high-voltage withstand voltage tester according to claim 4, characterized in that: The 1st pin of the relay JK5 is connected to the 4th pin of the relay JK3, the 3rd pin of the relay JK5 is connected to the 6th pin of the relay JK3, and the 4th pin of the relay JK5 is connected to the emitter of the triode Q1.

Images