CN203339658U - A leakage protection device - Google Patents

Abstract

The utility model discloses an electric leakage protection device which comprises a relay, a rectifier bridge, a silicon controlled rectifier, a voltage-regulator tube, a mutual inductor, and a safety protection circuit. The safety protection circuit is a charge-discharge circuit with an adjustable constant of charge time. The input end of the safety protection circuit is connected with the mutual inductor, and the output end of the safety protection circuit is connected with the control electrode of the silicon controlled rectifier. When abnormal interference or electric leakage happens outside, the mutual inductor generates an induction signal, and the safety protection circuit is used for charging. When the voltage of the output end of the safety protection circuit reaches the voltage of the control electrode of the silicon controlled rectifier, the silicon controlled rectifier is on, so as to control the relay contact to disconnect for electric leakage protection. The electric leakage protection device sets the constant of charge time of the safety protection circuit according to an actual power utilization environment, avoids the impact of an interference signal and prevents misoperation from happening in the condition that the sensitivity of the electric leakage protection device is guaranteed, is simple in structure, and is strong in universality.

Description

A leakage protection device

technical field

The utility model relates to leakage protection technology, in particular to a leakage protection device.

Background technique

The leakage protection device is a grounding protection device used to prevent personal electric shock and accidents caused by leakage. When the leakage current of the circuit or electrical equipment is greater than the set value of the device, or when people or animals are in danger of electric shock, it can act quickly to cut off the power supply of the accident, avoiding the expansion of the accident, and ensuring the safety of people and equipment. Existing earth leakage protection devices are prone to malfunction due to external interference during use. For example, there are other devices that easily interfere with the power supply next to or near the home appliances that use the leakage protection device. When these devices start or stop, they will generate strong interference signals, which will cause the leakage protection device to detect abnormalities and malfunction. Affect the normal use of home appliances.

Utility model content

The technical problem to be solved by the utility model is to provide a leakage protection device to solve the problem that the existing leakage protection device is easily disturbed and causes malfunction.

In order to achieve the above object, the utility model is achieved through the following technical solutions:

A leakage protection device, the device includes a relay, a rectifier bridge, a thyristor, a voltage regulator tube and a transformer, characterized in that the device also includes a safety protection circuit, one end of the relay is connected to the power line, and the other end It is connected to the input terminal of the rectifier bridge, the output terminal of the rectifier bridge is connected to the positive pole of the thyristor, the negative pole of the thyristor is grounded, the control pole of the thyristor is connected to the output terminal of the safety protection circuit, and the safe The input terminal of the protection circuit is connected with the transformer,

Wherein, the safety protection circuit is a charging and discharging circuit with an adjustable charging time constant.

Further, the safety protection circuit includes a charging and discharging circuit composed of a resistor and a capacitor, one end of the resistor is connected to the transformer, the other end of the resistor is connected to the capacitor, the other end of the capacitor is grounded, and the common end of the resistor and the capacitor is connected to the control electrode of the thyristor. connect.

Further, the resistance includes a variable resistor.

Further, the resistors are a series of resistors with different resistances connected in parallel, and each resistor is connected or disconnected through a corresponding switch.

Further, the charging time constant of the safety protection circuit ranges from 500 microseconds to 10 milliseconds.

Further, the default charging time constant of the safety protection circuit is 1 millisecond.

Further, the device is installed inside various household appliances and equipment, or installed on a power line plug.

Further, the thyristor includes a one-way thyristor.

Furthermore, when there is abnormal interference or leakage in the outside world, the transformer generates an induction signal, which is charged through the safety protection circuit. When the voltage at the output terminal of the safety protection circuit reaches the voltage of the control electrode of the thyristor, the thyristor is turned on, and the contact of the relay is controlled. Disconnect for leakage protection.

The leakage protection device described in the utility model adopts the charging and discharging circuit with adjustable charging time constant, which can realize the best power consumption purpose under different power consumption environments, and avoids the interference of interference signals under the premise of ensuring the sensitivity of the leakage protection device influence and the occurrence of malfunction.

Description of drawings

Fig. 1 is the structural block diagram of leakage protective device described in the utility model;

Fig. 2 is the circuit diagram of the leakage protection device provided by the first embodiment of the utility model;

Fig. 3 is the circuit diagram of the leakage protection device provided by the second embodiment of the utility model;

Fig. 4 is a schematic diagram of the effect of the leakage protection device of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is a structural block diagram of the leakage protection device described in the present invention. As shown in Figure 1, the leakage protection device includes a relay 101, a rectifier bridge 102, a thyristor 103, a voltage regulator tube 104, a safety protection circuit 105 and a transformer 106, wherein one end of the relay 101 is connected to a power line, The other end is connected to the input end of the rectifier bridge 102, the output end of the rectifier bridge 102 is connected to the positive pole of the thyristor 103, the negative pole of the thyristor 103 is grounded, and the control pole of the thyristor 103 is connected to the safety protection The output terminal of the circuit 105 is connected, the input terminal of the safety protection circuit 105 is connected with the transformer 106, and the safety protection circuit 105 is a charging and discharging circuit with adjustable charging time constant.

When there is abnormal interference or leakage in the outside world, the transformer 106 generates an induction signal, which is charged through the safety protection circuit 105. When the voltage at the output terminal of the safety protection circuit 105 reaches the gate voltage of the thyristor 103, the thyristor 103 is turned on and the relay is controlled. 101 contacts are disconnected for leakage protection.

In this embodiment, the charging time constant of the safety protection circuit is set according to the actual power consumption environment, and the influence of interference signals and the occurrence of malfunction are avoided under the premise of ensuring the sensitivity of the leakage protection device.

Fig. 2 is a circuit diagram of the leakage protection device provided by the first embodiment of the present invention. As shown in Figure 2, one end of the relay K1 is connected to the mains, and the other end is connected to the rectifier bridge composed of D1-D4. The output terminal of the rectifier bridge is connected to the positive pole of the thyristor Q1, the negative pole of the thyristor Q1 is grounded, the control pole of the thyristor Q1 is connected to the output terminal of the safety protection circuit, and a voltage regulator is connected between the thyristor Q1 and the ground. Tube D6, the safety protection circuit includes a charging and discharging circuit with an adjustable charging time constant composed of a variable resistor R3 and a capacitor C1, one end of the variable resistor R3 is connected to the output end of the mutual induction coil, and the other end of the variable resistor R3 One end is connected to the capacitor C1, the other end of the capacitor C1 is grounded, the common end of the variable resistor R3 and the capacitor C1 is used as the output end of the safety protection circuit, connected to the control electrode of the thyristor Q1, and R2 is the load. Among them, multiple contacts of the relay K1 are connected to the mains circuit (the contacts are respectively connected to the live wire N, the ground wire G and the neutral wire L), and the appropriate selection of the wire diameter and the number of winding turns of the relay coil can ensure its low Sufficient excitation power at voltage. The moving contact of the relay is a normally closed contact.

Specific working principle: When leakage or abnormal interference occurs in the outside world, the induction coil of the transformer induces a correspondingly changing signal (AC interference signal), and a changing voltage waveform is formed at both ends of the coil. When passing through the RC charging circuit, the C1 capacitor is charged. Charging, when the voltage at point B of the common terminal of the resistor and capacitor reaches the action voltage of the thyristor Q1 after charging, Q1 is turned on, which causes the contact of the relay K1 to be disconnected, and the entire circuit is disconnected to achieve the purpose of safety protection.

The voltage induced by the transformer coil is an AC interference signal, and C1 is charged through the RC charging circuit. When the positive half cycle of the AC interference signal passes, C1 is charged, and when the negative half cycle of the AC interference signal passes, C1 discharges through the load R2. Charging time constant τ=R3*C1. Since the capacitor C1 is a fixed value, the charging time constant is only related to the variable resistor R3. When the resistance value of R3 is larger, the charging time is longer; otherwise, the charging time is shorter.

What needs to be explained here is that the resistance value of R3 directly affects the use of the entire circuit. When the resistance value of R3 is too small, once the interference signal strikes, the voltage at point B will be charged to the operating voltage of Q1 in a very short period of time, causing malfunction . When the resistance value of R3 is too large, it will be difficult to charge the point B to the operating voltage of Q1, and when a normal leakage occurs, there may also be a problem of non-operation, which brings potential safety hazards. Therefore, the choice of R3 resistance is very important. In this embodiment, the time constant τ is selected from a range of 500 microseconds to 10 milliseconds, and different charging time constants can be set for different power consumption environments, so as to match different resistance values.

In the utility model, the variable resistor R3 includes a potentiometer or a sliding rheostat, etc., and the resistance value is adjusted to match the power consumption environment, so as to achieve the safest and most reliable power consumption purpose. After the variable resistor R3 is matched with C1, the charging time constant meets the requirement in the range of 500 microseconds to 10 milliseconds. Preferably, the charging time constant of the safety protection circuit is set to a resistance level corresponding to 1 millisecond by default. According to the gear position characteristics of the potentiometer, it can clearly prompt the operator how much the resistance value increases and how much the time constant increases after each rotation of a certain angle, so as to guide the operator concisely and clearly. It is easy for those skilled in the art to know that the resistance value can be changed by adjusting the potentiometer adjustment button. In order to accurately prompt the operator to adjust the resistance value of the potentiometer, on the potentiometer adjustment interface, set the dial corresponding to the angle and resistance value, and operate The operator only needs to rotate the corresponding angle according to the prompts of the dial to accurately obtain the change value of the resistance, thereby obtaining the change value of the charging time constant.

Thyristor, the abbreviation of silicon controlled rectifier element, is a high-power semiconductor device with a four-layer structure of three PN junctions, also known as a thyristor. With the characteristics of small size, relatively simple structure, and strong functions, it is one of the more commonly used semiconductor devices. The device is widely used in various electronic equipment and electronic products, and is mostly used for controllable rectification, inverter, frequency conversion, voltage regulation, non-contact switch, etc. Thyristors are widely used in various household appliances and equipment. In this embodiment, the thyristor Q1 is preferably a one-way thyristor. The unidirectional thyristor can be turned from off to on under the action of an external control signal, but once it is turned on, the external signal cannot turn it off, and it can only be turned off by removing the load or reducing the voltage at both ends.

In this embodiment, the live wire N, the ground wire G and the neutral wire L are respectively connected to the contacts of the relay. When the ground wire is a normally closed connection, the danger caused by the wrong connection of the live wire and wiring.

The leakage protection device described in this embodiment can be used inside various household appliances and equipment, and can also be installed on a power cord plug, which can effectively avoid malfunctions caused by interference signals and ensure the sensitivity of the device's actions.

Fig. 3 is a circuit diagram of the leakage protection device provided by the second embodiment of the present invention. As shown in Figure 3, one end of the relay K1 is connected to the mains, and the other end is connected to the rectifier bridge composed of D1-D4. The output terminal of the rectifier bridge is connected to the positive pole of the thyristor Q1, the negative pole of the thyristor Q1 is grounded, the control pole of the thyristor Q1 is connected to the output terminal of the safety protection circuit, and a voltage regulator is connected between the thyristor Q1 and the ground. Tube D6, the safety protection circuit includes a series of resistors with different resistances connected in parallel and a charging and discharging circuit with an adjustable charging time constant composed of capacitor C1. Each resistor is connected or disconnected through a corresponding switch, and a series of parallel connections One end of the common end of the resistors with different resistance values is connected to the output end of the mutual induction coil, the common end of the switch supporting each resistor is connected to the capacitor C1, and the other end of the capacitor C1 is grounded, and the series of parallel connected resistors with different resistance values The common terminal of the switch matched with the resistor and the common terminal of the capacitor C1 are used as the output terminal of the safety protection circuit, and are connected with the control pole of the thyristor Q1, and R2 is a load. Among them, the contacts of the relay K1 are connected to the mains input circuit (the contacts are respectively connected to the live wire N, the ground wire G and the neutral wire L), and the appropriate selection of the wire diameter and the number of winding turns of the relay coil can ensure its low voltage sufficient excitation power.

Specific working principle: When leakage or abnormal interference occurs in the outside world, the induction coil of the transformer induces a correspondingly changing signal (AC interference signal), and a changing voltage waveform is formed at both ends of the coil. When passing through the RC charging circuit, the C1 capacitor is charged. Charging, when the voltage of the selected resistance and capacitor common terminal B reaches the operating voltage of the thyristor Q1 after charging, Q1 is turned on, which causes the contact of the relay K1 to be disconnected, so that the entire circuit is disconnected to achieve safety protection. Purpose.

The difference between this embodiment and the embodiment shown in Figure 2 is that in this embodiment, a series of resistors with different resistances connected in parallel are connected or disconnected through their respective supporting switches, thereby changing the charging time constant of the safety protection circuit . The voltage induced by the transformer coil is an AC interference signal, and C1 is charged through the RC charging circuit. When the positive half cycle of the AC interference signal passes, C1 is charged, and when the negative half cycle of the AC interference signal passes, C1 discharges through the load R2. Charging time constant τ=R3*C1. Since the capacitor C1 is a fixed value, the charging time constant is only related to the access resistance of the charging circuit. The larger the resistance value of the access resistance, the longer the charging time; otherwise, the shorter the charging time.

Theoretically, the series of resistors with different resistances connected in parallel in this embodiment can cover all required resistances. Resistors with non-standard resistance values can be obtained by combining multiple resistors. Connect the resistance value through the matching switch of the selected resistance to match the power environment, so as to achieve the safest and most reliable power use purpose. After the series of resistors connected in parallel with different resistances are matched with C1, the charging time constant meets the requirement in the range of 500 microseconds to 10 milliseconds. Preferably, the charging time constant of the safety protection circuit is set to a resistance level corresponding to 1 millisecond by default. According to a series of resistors with different resistances connected in parallel, the required resistors can be accurately connected through respective matching switches, so as to determine the accurate charging time constant.

Compared with the embodiment shown in Figure 2, the leakage protection device described in this embodiment is a little more complicated, but it can accurately and quickly adjust the charging time constant of the safety protection circuit to match the current specific power consumption environment, and can effectively avoid external Malfunction caused by interference or electric leakage.

Fig. 4 is a schematic diagram of the effect of the leakage protection device of the present invention. Curve 1 in each figure represents the AC interference signal induced by the transformer coil, and curve 2 represents the action signal of the thyristor. Take the adjustable resistor resistances of 1K and 2K in the safety protection circuit as an example for comparison and description. Figure 4(a) shows the case where the adjustable resistor R3 is 1K, the AC interference signal generated by the induction coil is charged to C1 through the RC charging and discharging circuit, because the resistance of the resistor R3 is small, the charging time constant is small, and the AC interference The signal charges C1, and the common end of the adjustable resistor R3 and capacitor C1 reaches the operating voltage of the thyristor Q1 in a short time, thus causing malfunction.

Figure 4(b) shows the case where the adjustable resistor R3 is 2K, the induction coil generates an AC interference signal, and the capacitor C1 is charged through the RC charging and discharging circuit. The resistance of the adjustable resistor R3 is increased from the original 1K to 2K, and the charging current of the capacitor C1 through the resistor R3 is reduced by one time for the same interference signal, and the time required for charging to reach the operation of the thyristor Q1 is lengthened. In the positive half cycle of the AC interference signal, the capacitor C1 is charged, but the charged power is small compared to the 1K resistor, which is not enough to drive the thyristor Q1 to act; in the negative half cycle, the polarity is reversed, the capacitor C1 is discharged, and the charged capacitor is charged. If there is an interference signal in the next cycle, repeat the process; or when the interference signal disappears, the electricity on the capacitor C1 that has been partially charged is naturally discharged in the circuit, and finally the charged capacitor C1 The amount can not meet the operation requirements of the thyristor Q1, so the relay K1 does not malfunction.

It can be seen from Figure 4 that the charging time constant of the safety protection circuit is set according to the actual power consumption environment. On the premise of ensuring the sensitivity of the leakage protection device, the influence of interference signals and the occurrence of malfunctions can be avoided, and the best performance under different power consumption environments can be achieved. purpose of electricity use.

To sum up, for ordinary user groups, there are few electrical equipment that can cause large interference in their houses, and when the electricity environment is very good, the leakage protection device described in the utility model is difficult to be interfered and cause malfunction In this case, the charging constant is also set to be smaller, so that the interference signal and leakage signal can be quickly distinguished, and the leakage signal can be quickly judged and processed; for special user groups, such as large factories, industrial and mining sites, etc., this kind of In the process of starting and stopping large-scale equipment in the environment, it is easy to cause great harm to the circuit and cause extremely strong interference signals. In this extremely harsh power environment, it is necessary to avoid the problem of malfunction of the leakage protection circuit, so the charging constant needs to be set To avoid misoperation, but at the same time, it can clearly judge the interference signal and leakage signal. When the interference signal hits, the device will not operate, and when the leakage occurs, the device will operate for safety protection.

The above are only preferred embodiments of the present utility model and the applied technical principles. Any changes or replacements that can be easily imagined by anyone skilled in the art within the technical scope disclosed in the present utility model shall be covered by the present utility model. within the scope of protection.

Claims (7)

1. an earth leakage protective device; described device comprises relay, rectifier bridge, controllable silicon, voltage-stabiliser tube and instrument transformer; it is characterized in that, described device also comprises safety protective circuit, and described relay one termination enters power line; the other end is connected with the input of rectifier bridge; the output of described rectifier bridge is connected with silicon controlled is anodal, described silicon controlled minus earth, and described silicon controlled is controlled the utmost point and is connected with the output of safety protective circuit; the input of safety protective circuit is connected with instrument transformer

Wherein, described safety protective circuit is the adjustable charge-discharge circuit of charge constant.

2. earth leakage protective device according to claim 1; it is characterized in that; described safety protective circuit comprises the charge-discharge circuit that resistance and electric capacity form; resistance one end is connected with instrument transformer; the resistance other end is connected with electric capacity; electric capacity other end ground connection, resistance is controlled the utmost point with the common port of electric capacity with silicon controlled and is connected.

3. earth leakage protective device according to claim 2, is characterized in that, described resistance comprises variable resistance.

4. earth leakage protective device according to claim 2, is characterized in that, described resistance is the different resistance of a series of resistances that are connected in parallel, and each resistance is by supporting separately switch access or disconnection.

5. according to the described earth leakage protective device of one of claim 1 to 4, it is characterized in that, the charge constant scope of described safety protective circuit is 500 microseconds～10 millisecond.

6. earth leakage protective device according to claim 5, is characterized in that, the charge constant of described safety protective circuit is defaulted as 1 millisecond.

7. earth leakage protective device according to claim 1, is characterized in that, described controllable silicon comprises one-way SCR.

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