CN201903622U - Voltage resistance tester - Google Patents

Abstract

A voltage withstand tester, including a transformer and a load withstand voltage test module, the transformer includes an output voltage high end C, an output voltage low end D, the output voltage low end D is grounded and connected to the ground, and a load RL is connected across the output voltage high end C and Between the test terminals E, one end of the sampling resistor R1 is connected to the test terminal E, and the other end is grounded. The end connected to the test terminal E is the high voltage terminal P of the sampling resistor. The voltage of the sampling resistor R1 is input into the load withstand voltage test module, and the sampling resistor R1 is connected to the test terminal. E and the low end of the output voltage D, the high voltage end P of the sampling resistor is connected to the ground, and the low end D of the output voltage of the transformer is connected to the ground through the sampling resistor R1. The utility model can also detect normally when the tested equipment is grounded, and when the high-end C connection line connector of the output voltage touches the casing or the grounding point, the instrument can instantly disconnect the relay, and can cut off the output in time to protect the safety of the man-machine. Safety.

Description

A withstand voltage tester

technical field

The utility model relates to a withstand voltage tester, which is used for the normal test of the tested equipment when it is grounded, and protects the safety of people and instruments when the high-voltage output end is short-circuited to the instrument shell or the ground point. pressure tester.

Background technique

Withstanding voltage test refers to testing the withstand voltage capability of various electrical equipment, low-voltage electrical devices, insulating materials and insulating structures. The basic theory of the withstand voltage test is to expose a product to a very harsh environment. If the product can maintain a normal condition under such a harsh environment, it can be determined that it can work in a normal environment, and it must be able to Maintain normal conditions. Different products have different technical specifications. Basically, a high voltage is applied to the product during the withstand voltage test, and this voltage must last for a specified period of time. If the breakdown current of a component or device remains within the specified range within a specified time, it can be determined that the component or device is very safe to operate under normal conditions. Good design and good selection of insulating materials can protect the user.

The basic principle of the withstand voltage tester is shown in Figure 1: "A" and "B" are low-voltage input terminals, which are boosted by the transformer BL to generate high voltage at both ends of "C" and "D", and the "D" terminal is grounded and connected to the earth. The high voltage is output from the "C" terminal. E is the test terminal. The load RL to be tested is connected across the two ends of "C" and "E". When the leakage current generated after pressurization flows through the sampling resistor R1, a voltage drop occurs at both ends of the resistor, and the potential of point "P" rises. This voltage is sent to the MCU after amplified and AD conversion, compared with the preset value in the MCU, if it is less than the preset value, the tested load RL is qualified, if it is greater than the preset value, the tested load RL is unqualified, and the MCU sends out an alarm Command and disconnect relay K.

As shown in Figure 1, (1) The load RL under test must be suspended on the ground and cannot be connected to the ground, otherwise the sampling resistor R1 will not get the leakage current. (2) In actual work, due to misoperation, the high-voltage output terminal "C" connection line connector touches the casing or the grounding point, and the instrument cannot cut off the relay K at the transformer input terminal, so that the high-voltage output terminal is directly connected to the ground. A short circuit will cause damage to the machine or people.

Contents of the invention

The problem to be solved by the utility model is that the existing withstand voltage tester cannot cope with the grounding of the tested equipment, and there is no corresponding protection for the possible high voltage output terminal grounding of the instrument.

The technical scheme of the utility model is: a withstand voltage tester, including a transformer and a load withstand voltage test module, the transformer includes an output voltage high end C, an output voltage low end D, the output voltage low end D is grounded and connected to the earth, and the load RL It is connected between the high end C of the output voltage and the test terminal E. One end of the sampling resistor R1 is connected to the test terminal E, and the other end is grounded. The end connected to the test terminal E is the high voltage terminal P of the sampling resistor. In the module, the sampling resistor R1 is connected to the test terminal E and the low output voltage terminal D, the high voltage terminal P of the sampling resistor is connected to the ground, and the low terminal D of the output voltage of the transformer is connected to the ground through the sampling resistor R1.

The sampling resistor R1 shares a ground terminal with the low terminal D of the output voltage.

The utility model aims at the deficiencies in the prior art, and provides a device that can be detected normally even when the equipment to be tested is grounded, and the instrument can be disconnected instantly when the high-end C connection line connector of the output voltage touches the casing or the grounding point. Relay K can cut off the output in time to protect the safety of man-machine.

Description of drawings

FIG. 1 is a schematic circuit diagram of an existing withstand voltage tester.

Fig. 2 is a schematic circuit diagram of the withstand voltage tester of the present invention.

Detailed ways

As shown in Figure 2, the utility model includes a transformer and a load withstand voltage test module, including a transformer and a load withstand voltage test module, the transformer includes an output voltage high end C, an output voltage low end D, the output voltage low end D is grounded and connected to the earth, the load RL is connected between the high end C of the output voltage and the test terminal E. One end of the sampling resistor R1 is connected to the test terminal E, and the other end is grounded. The end connected to the test terminal E is the high voltage terminal P of the sampling resistor. In the test module, the sampling resistor R1 is connected to the test terminal E and the low output voltage terminal D, the high voltage terminal P of the sampling resistor is connected to the ground, and the low terminal D of the output voltage of the transformer is connected to the ground through the sampling resistor R1.

1) If one end of the load RL is connected to the earth, such as the protective grounding of the electrical equipment is connected to the earth through the ground wire in the city power grid, or a wire is directly connected to the earth, then this end is connected to the utility model. The test terminal E of the voltage tester is connected to the high end C of the output voltage. During the test, the leakage current on the load flows back to the transformer through the high voltage terminal P of the sampling resistor, the sampling resistor R1, and the low terminal D of the output voltage. The sampling resistor R1 produces a voltage drop. This voltage is amplified by the load withstand voltage test module and sent to the MCU after AD conversion. In the MCU, it is compared with the preset value. If it is less than the preset value, the tested load RL is qualified. If it is greater than the preset value Set the value, the load RL under test is unqualified, the MCU sends an alarm command and disconnects the relay K at the low-voltage input terminal of the transformer.

2) If the connector of the high-end C connection line of the output voltage touches the casing or the grounding point due to human error during the detection work, the high-voltage transformer will instantly generate a large current from point C of the high-end output voltage, and pass through the high-voltage end of the sampling resistor. P, sampling resistor R1, and point D at the low end of the output voltage flow back to the transformer. The voltage drop generated by the current flowing through the sampling resistor R1 is sent to the MCU after being amplified by the load withstand voltage test module and AD converted, so the value is much greater than the preset value, so the MCU sends an alarm command and disconnects the relay K. Cutting off the high-voltage output protects the safety of people and machines. After troubleshooting, press the reset button to return to the normal state.

Claims (2)

1. Hi-pot Tester, comprise transformer and load voltage-withstand test module, transformer comprises the high-end C of output voltage, output voltage low side D, output voltage low side D ground connection also links to each other with the earth, load RL is connected across between high-end C of output voltage and the test lead E, sample resistance R1 one end connects test lead E, one end ground connection, an end that is connected with test lead E is sample resistance high-pressure side P, the voltage input load voltage-withstand test module of sample resistance R1, it is characterized in that sample resistance R1 connects test lead E and output voltage low side D, sample resistance high-pressure side P is connected with the earth, and transformer output voltage low side D is connected with the earth through sample resistance R1.

2. a kind of Hi-pot Tester according to claim 1 is characterized in that earth terminal and the shared earth terminal of output voltage low side D of sample resistance R1.

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