CN205910273U - Two test circuit of earth -leakage protector - Google Patents

Abstract

The utility model provides a double test circuit of an electric leakage protector, which includes a first test circuit and a second test circuit connected in parallel with the first test circuit. 2. Test the operation indicator LED2 and the analog current limiting resistor R2, in which there is also a diode D2 connected in reverse parallel with LED2; the utility model provides a test circuit for the state of electric power safety equipped with a leakage protector, which passes the first and second tests The buttons cooperate with each other to form a double test button, so that on-site users and electricians can more accurately and reliably speculate on the working status of the leakage protector, and help solve hidden problems of the leakage protector.

Description

A dual test circuit for earth leakage protector

Technical field:

The utility model relates to a leakage protector equipped with electric power safety, which belongs to the field of low-voltage electric appliances, in particular to a double test circuit of the leakage protector.

Background technique

In the traditional power distribution system, leakage protectors are the most effective equipment to prevent personal electric shock accidents, so now it seems that leakage protectors are installed in every place that uses electricity. However, after installation, it does not mean absolute safety or eternal safety. Leakage protectors, like other electrical appliances, are sometimes damaged, or the tripping action with safety protection functions is slow due to aging, so if you do not perform regular functional inspections on it, Once the leakage protector fails, it cannot effectively implement its leakage tripping protection action, and dangerous electric shock accidents are prone to occur. Referring to Figure 1, the existing leakage protector function inspection method is to simulate a leakage current to flow through the electrical bypass between the input power supply and the output power supply of the leakage protector, and this current can make the zero sequence in the leakage protector If the transformer is unbalanced, if the current reaches the rated tripping current (usually 30mA), the leakage protector will trip.

According to Article 39 of the "Regulations on the Safety Supervision of Leakage Protectors" issued by the Ministry of Labor in 1990, the leakage protectors in operation must be inspected at least once a month to test the quality of the leakage protectors and ensure the safety of electricity use. .

As explained in Figure 1, the current household leakage protector RCD only has a normally open test button 7 (referred to as the first test button here), and a current limiting resistor 6 in series, and their two ends are connected to the input power supply 1 of the leakage protector and The terminal of the output power supply 5, once the test button 7 is triggered, the 30mA analog leakage current flowing through the button and the resistor will increase the current difference between the live wire and the neutral wire in the leakage protector by 30mA, and its zero sequence transformer 4 will also occur. Severe imbalance, the unbalanced electrical signal is amplified by the amplifier 3, and its current flows into the electromagnetic coil of the uncoupling device 2 to generate a strong magnetic field. The magnetic field pull makes the decoupling device loosen the contact point carrying the power supply, and the leakage protector trips accordingly.

Because there is only one test button to simulate a rated trip leakage current value to test whether the leakage protector will trip when it should trip, and there is no small leakage to test whether the leakage protector will continue to remain stable when it should not trip No tripping, no allergic tripping reactions.

Second, the user has no way of knowing whether the load connected to the output terminal of the leakage protector and its wiring have a low value of electrical leakage. This small leakage does not cause the leakage protector to trip because it does not usually reach the rated leakage current, and the user cannot There is no way to know the existence of small leakage, but it is likely to change at any time due to changes in the operating conditions of the load and the environment. Once the small leakage increases to close to the trip rated current, the leakage protector will react and trip. Cutting off the power supply to the load is a hidden danger. The leakage protector itself is too sensitive and there is a small leakage on the load wiring, which will cause the leakage protector to trip randomly and cut off the power supply, which will affect the reliability of power supply and bring great inconvenience to life and work.

At present, the home leakage protector has only one test button, and there is no test button indicator light.

Utility model content

The utility model aims to provide a test circuit equipped with a leakage protector state for electric power safety. The first and second test buttons cooperate with each other to form a double test button, so that on-site users and electricians can estimate the leakage protector more accurately and reliably. The working status of the leakage protector can better solve the above two hidden dangers of using the leakage protector.

A leakage protector double test circuit, comprising a first test circuit and a second test circuit connected in parallel with the first test circuit, the second test circuit includes a second test button SW2 and a second test operation indicator light connected in series in sequence LED2 and analog current limiting resistor R2, which also has a diode D2 in antiparallel with LED2.

In the double test circuit of the leakage protector mentioned above, the common input terminals of the first test circuit and the second test circuit are connected to the neutral line of the power supply input terminal, and the common output terminals are connected to the live line of the load output terminal.

In the dual test circuit of the leakage protector mentioned above, the first test circuit includes the first test button SW1 connected in series with a current limiting resistor.

In the double test circuit of the above leakage protector, the second test circuit will simulate a low-value leakage when it is triggered, and the leakage amount is 40% to 49% of the rated tripping leakage current of the leakage protector, which is used for testing the leakage The tripping response of the protector.

The above-mentioned dual test circuit for a leakage protector further includes a leakage protector, and the tripping response time of the leakage protector in response to the rated tripping leakage current is 0.2 seconds or less. But there will be no tripping action for the leakage current lower than half of the rated tripping leakage current.

In the dual test circuit of the leakage protector mentioned above, when the first test button SW1 is triggered, it will simulate a 30mA leakage for the circuit in the matching leakage protector, because the simulated leakage value is equal to the rated tripping of the leakage protector Leakage value, so that the leakage protector reacts to trip and cut off its output power.

In the dual test circuit of the leakage protector mentioned above, once the first test button SW1 is triggered, the 30mA analog leakage current flowing through the first test button and the resistor will increase the current difference between the live wire and the neutral wire in the leakage protector by 30mA , the zero-sequence transformer will be seriously unbalanced. The unbalanced electrical signal is amplified by the amplifier, and its current flows into the electromagnetic coil of the uncoupling device to generate a strong magnetic field. The magnetic field pull makes the uncoupling device loosen the contact point carrying the power supply, and the leakage protector So it tripped.

A leakage protector double test circuit adopting the above-mentioned technical scheme adopts the following test method, including the following test steps:

Step 1. Once the first test button of the leakage protector is triggered, it will simulate a 30mA leakage current to the circuit in the matching leakage protector, so that the leakage protector will trip and cut off its output power. If the leakage protector If there is no response, it means that the earth leakage protector does not react well and is not quick to the leakage, and further inspection is needed;

Step 2. The second test circuit includes a normally open (NO) second test button. Once it is pressed, a low-value analog leakage is generated, and the leakage amount is 40% of the rated tripping leakage current of the leakage protector. to 49%, if the output terminal of the leakage protector is not connected to any load and trips, it means that the leakage protector itself is unstable, and the sensitivity is too high and it is easy to malfunction. Further inspection is required. If there is a load and there is a tripping response to the second test button, it means that there is a small leakage current in the load and its wiring, and further electrical inspection is required.

In the above-mentioned test method of the double test circuit of the leakage protector, if the leakage protector has a tripping response to the previous first test button but does not respond to the second test button, it means that the leakage protector is in a normal state, and the wiring and load at the output end are also normal. good.

In the test method of the above-mentioned leakage protector double test circuit, when the first test button SW1 in the first test circuit is pressed, because there is an AC voltage at both ends of the circuit and a current limiting resistor in the circuit, an approximately 30mA (effective value) , RMS) simulated leakage occurs in this first test circuit, and the current difference between the live wire and the neutral wire in the leakage protector also correspondingly presents the same current waveform, because the current difference reaches the tripping rated leakage of the leakage protector value (30mA), the zero-sequence transformer inside the leakage protector is seriously unbalanced, triggering the release to trip and cut off the power supply;

When the leakage protector is in normal operation and the second test button SW2 in the second test circuit is pressed, the AC power supply (220V) at both ends of the circuit and the current limiting resistor (16K ohm) in the circuit will generate a simulated leakage , the current value is 13.8mA (effective value, RMS), and the current difference between the live wire and the neutral wire in the leakage protector also correspondingly presents the same current waveform, but because the current difference does not reach the tripping rated leakage of the leakage protector Half of the value (30mA), so it will not trip the leakage protector that is not connected to the load.

If the wiring of the output terminal of the leakage protector or the live wire of the electrical load has a small leakage to the ground, such as 14mA, the simulated low-value leakage generated by triggering the second test button will be added to the actual live wire leakage of the wiring load. The current difference between the live wire and the neutral wire in the leakage protector increases accordingly. Once the current difference is close to the trip rated leakage value (30mA), the leakage protector will trip.

When the second test button SW2 is pressed, the low-value simulated leakage current passes through the indicator LED2, and the LED2 lights up to indicate.

As shown in Figure 2, once the first test button of the leakage protector is triggered, it will simulate a 30mA leakage current to the circuit in the matching leakage protector, causing the leakage protector to trip and cut off its output power. If the leakage protector does not respond, it means that the leakage protector has a poor response to the leakage and is not quick, and further inspection is required.

Also as shown in Figure 2, the second test button method described in the utility model is to connect a new similar circuit in parallel on the first test circuit of the leakage protector, which is called the second test circuit.

The second test circuit includes a normally open (NO) second test button, once it is pressed, a low-value analog leakage is generated, and the leakage is 40% to 49% of the rated tripping leakage current of the leakage protector , if the output terminal of the leakage protector is not connected to any load and trips, it means that the leakage protector itself is unstable, and the sensitivity is too high and it is easy to malfunction, and further inspection is needed. If the leakage protector in good condition is connected to the load and has a tripping response to the second test button, it means that there is a small leakage in the load and its wiring, and further electrical inspection is required.

If the leakage protector responds to the tripping of the previous first test button but does not respond to the second test button, it means that the leakage protector is in normal state, and the wiring and load of its output terminal are also good. In short, we can know the following reliable and comprehensive leakage protector status according to the tripping or non-tripping response of the double test button

The utility model also provides a test indicator light, which displays the second test button for displaying the operation state, and improves the human interface between the user and the function of the test button.

Description of drawings

Figure 1 is a schematic diagram of the internal circuit structure and load wiring of a traditional single-phase leakage protector;

Fig. 2 is an explanatory diagram of the dual test button scheme of the leakage protector of the present invention;

Fig. 3 is the circuit embodiment of the utility model test double button method;

Fig. 4 is the current waveform of the utility model after triggering the first test button;

Fig. 5 is the current waveform of the utility model after triggering the second test button;

Fig. 6 is a schematic diagram of 14mA leakage to ground of the load live wire of the utility model;

Fig. 7 is the current difference between the live wire and the neutral wire triggered by the second test button SW2 of the present invention.

detailed description

The utility model will be further described and explained in detail below in conjunction with an implementation example and accompanying drawings. It should be understood that the specific implementation described here is only used to explain the method of the utility model, but the implementation of the utility model is not limited to this example.

As shown in Figures 1 to 7, a leakage protector double test circuit includes a first test circuit a, a second test circuit b connected in parallel with the first test circuit a, and the second test circuit b includes a second test circuit b connected in series in sequence Test the button SW2, the second test operation indicator LED2 and the analog current limiting resistor R2, wherein there is also a diode D2 connected in antiparallel with the LED2.

The common input terminal of the first test circuit a and the second test circuit b is connected to the neutral wire of the power input, and the common output terminal is connected to the live wire of the load output.

The first test circuit a includes a first test button SW1 connected in series with a current limiting resistor.

When the second test circuit b is triggered, a low-value leakage (13.8mA) will be simulated, and the leakage amount is 40% to 49% of the rated tripping leakage current of the leakage protector, which is used to test the tripping response of the leakage protector.

It also includes leakage protectors, which have a tripping response time of 0.2 seconds or less in response to the rated tripping leakage current, but will not have any tripping action for leakages lower than half of the rated tripping leakage current.

When the first test button SW1 is triggered, it will simulate a 30mA leakage current to the circuit in the matching leakage protector. Since the simulated leakage value is equal to the rated trip leakage value of the leakage protector, the leakage protector will start a tripping response. And cut off its output power.

Once the first test button SW1 is triggered, the 30mA analog leakage current flowing through the first test button and the resistor will increase the current difference between the live wire and the neutral wire in the leakage protector by 30mA, and its zero sequence transformer will also be severely unbalanced , the unbalanced electrical signal is amplified by the amplifier, and its current flows into the electromagnetic coil of the uncoupler to generate a strong magnetic field. The magnetic field pull makes the uncoupler loosen the contact point carrying the power supply, and the leakage protector trips accordingly.

A method for testing a double test circuit of a leakage protector, comprising the following test steps:

Step 1. Once the first test button of the leakage protector is triggered, it will simulate a 30mA or higher leakage to the circuit in the matching leakage protector, so that the leakage protector will trip and cut off its output power. If If the earth leakage protector does not respond, it means that the earth leakage protector responds poorly and is not quick to the leakage, and further inspection is needed;

Step 2. The second test circuit includes a normally open (NO) second test button. Once it is pressed, a low-value analog leakage is generated, and the leakage amount is 40% of the rated tripping leakage current of the leakage protector. To 49%, if the output terminal of the leakage protector is not connected to any load and trips, it means that the leakage protector itself is unstable, and the sensitivity is too high and it is easy to malfunction, and further inspection is needed. If the leakage protector in good condition is connected to the load and has a tripping response to the second test button, it means that there is a small leakage in the load and its wiring, and further electrical inspection is required.

If the leakage protector responds to the tripping of the previous first test button but does not respond to the second test button, it means that the leakage protector is in normal state, and the wiring and load of its output terminal are also good.

When the first test button SW1 in the first test circuit is pressed, due to the AC voltage at both ends of the circuit and the current limiting resistor in the circuit, a simulated leakage of about 30mA (effective value, RMS) occurs in the first test circuit. In the test circuit, the current difference between the live wire and the neutral wire in the leakage protector also presents the same current waveform accordingly. Since the current difference reaches the trip rated leakage value (30mA) of the leakage protector, the zero sequence in the leakage protector As a result, the transformer is seriously out of balance, triggering the release to trip and cut off the power supply;

When the leakage protector is in normal operation and the second test button SW2 in the second test circuit is pressed, the AC power supply (220V) at both ends of the circuit and the current limiting resistor (16K ohm) in the circuit will generate a simulated leakage , the current value is 13.8mA (effective value, RMS), and the current difference between the live wire and the neutral wire in the leakage protector also correspondingly presents the same current waveform, but because the current difference does not reach the tripping rated leakage of the leakage protector Half of the value (30mA), so it will not trip the leakage protector that is not connected to the load.

If there is a small leakage of 14mA to the ground in the wiring of the output terminal of the leakage protector or the live wire of the electrical load (as shown in c in Figure 6), the simulated low-value leakage that occurs when the second test button (point a to point b in Figure 7) is triggered It will be added to the live wire leakage that actually occurs in the wiring load, and the current difference between the live wire and the neutral wire in the leakage protector will increase accordingly (point d to point e). Once the current difference is close to the rated leakage value of the trip ( 30mA), the leakage protector will trip (points b and e in Figure 7).

When the second test button SW2 is pressed, the low-value simulated leakage current passes through the indicator LED2, and the LED2 lights up to indicate.

A simple circuit of a specific implementation of the second test button method of the present invention is shown in FIG. 3 . The circuit includes a test button SW2, a series analog current limiting resistor R2 and a test operation indicator LED2, and the LED2 is connected in antiparallel with a diode D2. The entire second test circuit is connected in parallel to the first test circuit. One side of the two parallel circuits is connected to the neutral wire (N1) of the input power supply of the leakage protector, and the other side of the circuit is connected to the live wire (L2) of the output power supply of the leakage protector.

The circuit of the second test button in Fig. 3 has no influence on the normal operation and protection function of the matching earth leakage protector. Like the original first test button, the contact point of the second test button SW2 is normally open (NO). If it is not pressed, the power supply at both ends of the test circuit will not form an electrical circuit, and no current will occur in this test. On the circuit, there is no power loss at all.

As shown in Figure 4, when the first test button SW1 in the first test circuit is pressed (point a in the upper figure in Figure 4), since there is an AC voltage at both ends of the circuit and a current limiting resistor in the circuit, a The simulated leakage of about 30mA (effective value, RMS) occurs in this first test circuit, and the current difference between the live line and the neutral line in the leakage protector also correspondingly presents the same current waveform (the lower figure in Figure 4), because This current difference reaches the rated leakage value (30mA) of the leakage protector, and the zero-sequence transformer inside the leakage protector is seriously unbalanced, triggering the release to trip and cut off the power supply (points b and d in Figure 4).

When the leakage protector is operating normally, and the second test button SW2 in the second test circuit is pressed (point a in the upper figure in Figure 5), the AC power supply (220V) at both ends of the circuit and the current limit in the circuit The resistance (16K ohm) produces a simulated leakage current with a current value of 13.8mA (effective value, RMS), and the current difference between the live wire and the neutral wire in the leakage protector also correspondingly presents the same current waveform (lower diagram in Figure 5 ), but since the current difference does not reach half of the rated leakage value (30mA) of the leakage protector, it will not trip the leakage protector that is not connected to the load.

As shown in the lower left corner of Figure 6, if there is a small leakage c, such as 14mA, to the ground in the wiring of the output terminal of the leakage protector or the live wire of the electrical load, please refer to Figure 7 to trigger the second test button (a in the upper figure of Figure 7 From point b to point b), the simulated low-value leakage will be added to the actual live wire leakage that occurs in the wiring load, so that the current difference between the live wire and the neutral wire in the leakage protector will increase accordingly (d in the lower figure of Figure 7 point to point e), once the current difference is close to the tripping rated leakage value (30mA), the leakage protector will trip (points b and e in Figure 7).

On the right side of Fig. 6, when the second test button SW2 is pressed to trigger the low-value analog leakage current to pass through the indicator LED2, the LED2 will light up to indicate.

In terms of operational safety, since the second test button circuit and the first test circuit are both stored in the plastic insulation shell of the earth leakage protector, and the hand-touch heads of the first test button and the second test button are also plastic, so the on-site use Operators and electricians have absolutely no problems in terms of operational safety.

The above descriptions are only preferred feasible embodiments of the present utility model, and are not intended to limit the patent protection scope of the present utility model. In addition to the above embodiments, the utility model can also have other implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The undescribed technical features of the utility model can be realized by or adopting the prior art, and will not be repeated here.

Claims (7)

1. a kind of leakage protector double test circuit, comprises the first test circuit (a), is characterized in that: also comprises the second test circuit (b) that is connected in parallel with the first test circuit (a), the second test circuit ( b) Including a second test button SW2, a second test operation indicator LED2 and an analog current limiting resistor R2 connected in series in sequence, and there is also a diode D2 connected in antiparallel to the LED2. 2. A kind of leakage protector double test circuit according to claim 1, is characterized in that: its input terminal of the first test circuit (a) and the second test circuit (b) are connected to the power input neutral line, and the output terminal is connected to The live wire of the load output. 3. A double test circuit for leakage protector according to claim 1, characterized in that: the first test circuit (a) comprises a first test button SW1 connected in series with a current limiting resistor R1. 4. The double test circuit of a leakage protector according to claim 1, characterized in that: the second test circuit (b) will simulate a low-value leakage when triggered, and the amount of leakage is the rated value of the leakage protector. 40% to 49% of the tripping leakage current, used to test the tripping response of the leakage protector. 5 . The double test circuit of a leakage protector according to claim 1 , further comprising a leakage protector whose tripping reaction time in response to the rated tripping leakage current is 0.2 seconds or less. 5 . 6. A leakage protector double test circuit according to claim 3, characterized in that: when the first test button SW1 is triggered, it will simulate a 30mA leakage for the circuit in the matching leakage protector, so that The RCD reacts by tripping and cuts off its output power. 7. The double test circuit of a leakage protector according to claim 4, characterized in that: once the first test button SW1 is triggered, the 30mA analog leakage current flowing through the button and the resistor will make the fire wire and the live wire in the leakage protector The current difference of the neutral line increases by 30mA, and the zero-sequence transformer is seriously unbalanced. The unbalanced electrical signal is amplified by the amplifier, and the current flows into the electromagnetic coil of the decoupler to generate a strong magnetic field. The magnetic field pull makes the decoupler loose. The contact point of the power supply, the leakage protector will trip.