An insulation performance testing circuit

Abstract

An insulation performance testing circuit includes a device under test (DUT), a relay, a PLC controller, and an insulation resistance meter. Both ends of the DUT are connected to the relay. The relay is connected to the insulation resistance meter, the PLC controller, and a power supply. The alarm output interface of the insulation resistance meter is connected to the input terminal of the PLC controller. The output terminal of the PLC controller is connected to a signal indicator and the relay coil. This invention allows for insulation testing of the DUT using the insulation resistance meter and feeds the test results back to the PLC controller. The relay allows switching between insulation testing and open / short circuit testing, resulting in high testing efficiency. The signal indicator displays the results intuitively, avoiding human error caused by manual reading.

Description

Technical Field

[0001] This utility model relates to the field of electrical engineering, and more particularly to electrical performance testing technology, especially an insulation performance testing circuit. Background Technology

[0002] Insulation performance is a key indicator for measuring the safety and reliability of electrical products. During quality inspection of existing electrical products such as temperature sensors and motor coils, it is necessary to check whether the terminals of the tested component are insulated from the casing, and also to check whether the two ends of the tested component have open circuits or short circuits due to manufacturing defects. Traditional insulation resistance testing is usually performed by operators using a handheld megohmmeter to test each component individually and manually record the results. This method is inefficient, the test results are easily affected by human factors, and the testing process is inconvenient. Summary of the Invention

[0003] The purpose of this invention is to provide an insulation performance testing circuit that solves the technical problem of low efficiency in insulation performance testing in the prior art.

[0004] This invention relates to an insulation performance testing circuit, comprising a relay, a PLC controller, and an insulation resistance meter. The relay includes an input circuit, a first output circuit, and a second output circuit. Each of the first and second output circuits includes a moving contact, a first stationary contact, and a second stationary contact. The moving contact in the first output circuit is electrically connected to a first test terminal, and the moving contact in the second output circuit is electrically connected to a second test terminal. The first stationary contacts of both the first and second output circuits are connected to the L terminal of the insulation resistance meter. The second stationary contact of the first output circuit is connected to a 5V DC power supply. The second stationary contact of the two output circuits is connected to one end of a first resistor and the analog input terminal of the PLC controller. The other end of the first resistor is connected to the 0V terminal of the PLC controller. The E terminal of the insulation resistance meter is connected to the ground terminal, which is connected to the outer casing of the device under test. The common terminal of the PLC controller is connected to one end of the alarm output interface of the insulation resistance meter, one end of the positioning switch, and one end of the reset switch. The other ends of the positioning switch, the reset switch, and the alarm output interface of the insulation resistance meter are respectively connected to the input terminal of the PLC controller. The common terminal of the PLC controller is connected to a 24V DC power supply. The output terminal of the PLC controller is connected to the input circuit of the signal indicator device and the relay.

[0005] Furthermore, the first test terminal is electrically connected to the first end of the device under test, the second test terminal is electrically connected to the second end of the device under test, and the grounding terminal is electrically connected to the outer casing of the device under test.

[0006] Furthermore, the signal indicating device includes a short-circuit indicator, an open-circuit indicator, an alarm indicator, and a pass indicator. The output terminal of the PLC controller is connected to one end of the short-circuit indicator, one end of the open-circuit indicator, one end of the alarm indicator, one end of the pass indicator, and one end of the input circuit of the relay, respectively. The other ends of the short-circuit indicator, the open-circuit indicator, the alarm indicator, the pass indicator, and the input circuit of the relay are respectively connected to a DC 0V power supply.

[0007] Furthermore, the output terminal of the PLC controller is connected to one end of the buzzer, and the other end of the buzzer is connected to a DC 0V power supply.

[0008] Furthermore, the common terminal of the PLC controller is connected to one end of the power indicator light, and the other end of the power indicator light is connected to a DC 0V power supply.

[0009] Furthermore, the relay model is DS4E-S-DC24V-1C-N126.

[0010] Furthermore, the insulation resistance meter is model ZC93-3.

[0011] Compared with existing technologies, the advantages of this invention are positive and significant. This invention uses an insulation resistance meter to perform insulation testing on the tested component and feeds the test results back to the PLC controller. A relay allows switching between insulation testing and open / short circuit testing, resulting in high testing efficiency. A signal indicator device visually displays the judgment results, avoiding human error caused by manual reading. Attached Figure Description

[0012] Figure 1 This is the circuit diagram of this utility model.

[0013] The markings in the diagram are: 1. Test device; 2. PLC controller; 3. Insulation resistance meter; KA1. Relay; R1. First resistor; SPK1. Buzzer; HL1. Short circuit indicator; HL2. Open circuit indicator; HL3. Alarm indicator; HL4. Qualified indicator; HL5. Power indicator; SA1. Position switch; SA2. Reset switch. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this does not limit the present invention.

[0015] like Figure 1As shown, this utility model discloses an insulation performance testing circuit, comprising a relay KA1, a PLC controller 2, and an insulation resistance meter 3. The relay KA1 includes an input circuit, a first output circuit, and a second output circuit. Each of the first and second output circuits includes a moving contact, a first stationary contact, and a second stationary contact. The moving contact in the first output circuit is electrically connected to a first test terminal, and the moving contact in the second output circuit is electrically connected to a second test terminal. The first stationary contacts of both the first and second output circuits are connected to the L terminal of the insulation resistance meter 3. The second stationary contact of the first output circuit is connected to a 5V DC power supply. The second static contact of the second output circuit is connected to one end of the first resistor R1 and the analog input terminal of the PLC controller 2. The other end of the first resistor R1 is connected to the 0V terminal of the PLC controller 2. The E terminal of the insulation resistance meter 3 is connected to the ground terminal. The common terminal of the PLC controller 2 is connected to one end of the alarm output interface of the insulation resistance meter 3, one end of the positioning switch SA1, and one end of the reset switch SA2. The other ends of the positioning switch SA1, the reset switch SA2, and the alarm output interface of the insulation resistance meter 3 are respectively connected to the input terminal of the PLC controller 2. The common terminal of the PLC controller 2 is connected to a DC 24V power supply. The output terminal of the PLC controller 2 is connected to the input circuit of the signal indicator device and the relay KA1.

[0016] Furthermore, the first test terminal is electrically connected to the first terminal of the device under test 1, the second test terminal is electrically connected to the second terminal of the device under test 1, and the grounding terminal is electrically connected to the outer casing of the device under test 1.

[0017] Furthermore, the signal indicating device includes a short-circuit indicator HL1, an open-circuit indicator HL2, an alarm indicator HL3, and a pass indicator HL4. The output terminal of the PLC controller 2 is connected to one end of the short-circuit indicator HL1, one end of the open-circuit indicator HL2, one end of the alarm indicator HL3, one end of the pass indicator HL4, and one end of the input circuit of the relay KA1. The other ends of the short-circuit indicator HL1, the open-circuit indicator HL2, the alarm indicator HL3, the pass indicator HL4, and the input circuit of the relay KA1 are connected to a DC 0V power supply.

[0018] Furthermore, the output terminal Y3 of the PLC controller 2 is connected to one end of the buzzer SPK1, and the other end of the buzzer SPK1 is connected to a DC 0V power supply. The buzzer SPK1 can emit an audible alarm when the alarm indicator HL3 is lit, prompting the operator that the tested part 1 is a defective part, thus preventing the operator from accidentally putting the defective part into the qualified part.

[0019] Furthermore, the common terminal of the PLC controller 2 is connected to one end of the power indicator HL5, and the other end of the power indicator HL5 is connected to a DC 0V power supply. The power indicator HL5 can be used to determine whether the power supply is working properly.

[0020] Furthermore, the relay KA1 can be a DS4E-S-DC24V-1C-N126 type relay manufactured by Panasonic.

[0021] Furthermore, insulation resistance meter 3 can be the ZC93-3 type insulation resistance meter manufactured by Shanghai Anbiao Electronics Co., Ltd.

[0022] In use, the two ends of the component under test 1 are first connected to the first test terminal and the second test terminal, respectively. The housing of the component under test 1 is connected to the ground terminal. Then, the positioning switch SA1 is pressed. After receiving the signal, the input terminal of the PLC controller 2 starts the test. The input circuit of the relay KA1 is the coil of the relay. During the test, the output terminal of the PLC controller 2 corresponding to the input circuit of the relay KA1 outputs a high level to energize the coil of the relay KA1, causing the moving contacts of the first output circuit and the second output circuit of the relay KA1 to close with the first stationary contact. The insulation resistance meter 3 is used to measure whether there is insulation between the terminals of the component under test 1 and the housing.

[0023] In PLC controller 2, a delay is set. The alarm output interface of insulation resistance meter 3 is a passive switch. One end is connected to the common terminal of PLC controller 2, which has a 24V voltage. If the insulation of the tested component 1 is unqualified, the two ends of the alarm output interface of insulation resistance meter 3 are short-circuited, and the other end can output a high-level signal. After receiving the high-level signal from insulation resistance meter 3 within the delay time, the input terminal of PLC controller 2 determines that the tested component 1 is unqualified. The output terminal of PLC controller 2 controls the alarm indicator HL3 to light up, and the buzzer SPK1 sounds an alarm. The unqualified component needs to be removed, and the alarm state is cleared by pressing the reset switch SA2 before the next tested component can be tested.

[0024] If the insulation of the device under test (DUT) 1 is qualified, and the input terminal of the PLC controller 2 does not receive a high-level signal from the insulation resistance meter 3 within the delay time, then the measurement continues to check whether there is a short circuit or open circuit between the two ends of DUT 1. The output terminal corresponding to the input circuit of the PLC controller 2 and relay KA1 is changed to a low level, the coil of relay KA1 is de-energized, and the moving contact of the first output circuit and the second output circuit of relay KA1 closes with the second stationary contact. The first end of DUT 1 is connected to a 5V DC power supply, and the second end of DUT 1 is connected to the 0V terminal of the PLC controller 2 via the first resistor R1. The potential of the second end of DUT 1 can be measured through the analog input terminal ADC1. If the voltage measured by the analog input terminal ADC1 is too high, for example, close to 5V, then... If the voltage measured at the analog input terminal ADC1 is too low (e.g., close to 0V), it indicates an open circuit between the two ends of the device under test (DUT), and DUT is deemed unqualified. PLC controller 2 illuminates the short circuit indicator HL1 and alarm indicator HL3, and buzzer SPK1 sounds. If the voltage measured at the analog input terminal ADC1 is too low (e.g., close to 0V), it indicates an open circuit between the two ends of DUT, and DUT is deemed unqualified. PLC controller 2 illuminates the open circuit indicator HL2 and alarm indicator HL3, and buzzer SPK1 sounds. Pressing the reset switch SA2 clears the alarm, and the test proceeds to the next DUT. If the voltage measured at the analog input terminal ADC1 is within the acceptable range, PLC controller 2 illuminates the pass indicator HL4, indicating that DUT is qualified and can proceed to the next DUT.

Claims

1. An insulation performance testing circuit, comprising a relay, a PLC controller, and an insulation resistance meter, wherein the relay comprises an input circuit, a first output circuit, and a second output circuit, and each of the first and second output circuits comprises a moving contact, a first stationary contact, and a second stationary contact, characterized in that: The moving contact in the first output circuit is electrically connected to a first test terminal, and the moving contact in the second output circuit is electrically connected to a second test terminal. The first stationary contact of both the first and second output circuits is connected to the L terminal of the insulation resistance meter. The second stationary contact of the first output circuit is connected to a 5V DC power supply. The second stationary contact of the second output circuit is connected to one end of a first resistor and the analog input terminal of the PLC controller. The other end of the first resistor is connected to the 0V terminal of the PLC controller. The E terminal of the insulation resistance meter is connected to the ground terminal. The common terminal of the PLC controller is connected to one end of the alarm output interface of the insulation resistance meter, one end of the positioning switch, and one end of the reset switch. The other ends of the positioning switch, the reset switch, and the alarm output interface of the insulation resistance meter are respectively connected to the input terminal of the PLC controller. The common terminal of the PLC controller is connected to a 24V DC power supply. The output terminal of the PLC controller is connected to the input circuit of the signal indicator and the relay.

2. The insulation performance testing circuit as described in claim 1, characterized in that: The first test terminal is electrically connected to the first end of the device under test, the second test terminal is electrically connected to the second end of the device under test, and the grounding terminal is electrically connected to the outer casing of the device under test.

3. The insulation performance testing circuit as described in claim 1, characterized in that: The signal indicating device includes a short-circuit indicator, an open-circuit indicator, an alarm indicator, and a pass indicator. The output terminal of the PLC controller is connected to one end of the short-circuit indicator, one end of the open-circuit indicator, one end of the alarm indicator, one end of the pass indicator, and one end of the input circuit of the relay, respectively. The other ends of the short-circuit indicator, the open-circuit indicator, the alarm indicator, the pass indicator, and the input circuit of the relay are respectively connected to a DC 0V power supply.

4. The insulation performance testing circuit as described in claim 1, characterized in that: The output terminal of the PLC controller is connected to one end of the buzzer, and the other end of the buzzer is connected to a DC 0V power supply.

5. The insulation performance testing circuit as described in claim 1, characterized in that: The common terminal of the PLC controller is connected to one end of the power indicator light, and the other end of the power indicator light is connected to a DC 0V power supply.

6. The insulation performance testing circuit as described in claim 1, characterized in that: The relay model is DS4E-S-DC24V-1C-N126.

7. The insulation performance testing circuit as described in claim 1, characterized in that: The insulation resistance meter is model ZC93-3.

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