CN105006708A - Protection-mode-convertible electric leakage protection plug - Google Patents

Abstract

The invention provides a protection-mode-convertible electric leakage protection plug which is composed of a shell, plug pins, phase wires, zero wires, ground wires, a zero sequence current transformer, a test loop, an electromagnetic tripping and latching device, a ground wire fault current detection circuit, a ground wire fault voltage detection circuit, first and second conversion switches, first and second amplification circuits and a unidirectional conduction circuit. The secondary winding output end of the zero sequence current transformer is connected with the input end of the first amplification circuit. The unidirectional conduction circuit is connected with the third intermediate input end of the first amplification circuit. The secondary winding output end of a ground wire live detection inductor is connected with the input end of the second amplification circuit via the second conversion switch. The trigger output end of the second amplification circuit is connected with the control electrode of a second silicon controlled rectifier. According to the electric leakage protection plug, a ground wire fault current protection mode and a ground wire fault voltage mode can be convertibly selected so that a problem of mis-tripping of the electric leakage protection plug can be solved and electricity utilization is ensured to be safer for people.

Description

Leakage protection plug with convertible protection mode

technical field

The invention relates to the technical field of electricity safety protection, in particular to a leakage protection plug with switchable protection modes.

Background technique

Existing leakage protection plugs can be divided into two types of products: ground fault current detection and protection and ground fault voltage detection and protection according to the detection and protection methods for live wires.

Chinese patent document CN1142618C discloses a leakage protection plug capable of detecting ground wire fault current. The leakage protection plug can detect whether there is a fault current in the ground wire when the ground wire is accidentally electrified due to an abnormal ground protection system, and the ground wire fault current reaches When the preset threshold value is reached, it will immediately cut off the phase wire, neutral wire and ground wire. It can be seen from this that, as long as the fault current of the ground wire of this kind of leakage protection plug reaches a predetermined threshold value, the leakage protection plug will trip regardless of the fault voltage carried by the ground wire. Low, but because the ground wire has a fault current greater than the predetermined threshold, it will cause the leakage protection plug to trip by mistake, causing people to be unable to use it normally.

Chinese patent document CN202142735U also discloses a leakage protection plug capable of detecting ground fault voltage. This leakage protection plug will automatically trip when the grounding system is abnormal and the ground fault voltage reaches a predetermined threshold, and it will be disconnected from the ground fault current. size is irrelevant. Therefore, when the fault voltage of the leakage protection plug in the ground wire is an induced voltage greater than the predetermined threshold but the fault current flowing through the ground wire is very weak, it will also cause the leakage protection plug to trip by mistake, causing people to be unable to use it normally. .

For this reason, the electric water heater market urgently needs a kind of product that can adapt to the ground wire electrification protection technology of various electricity consumption environments, thereby can reach and reduce the probability of returning goods and repairing after sale.

Contents of the invention

The purpose of the present invention is to provide a leakage protection plug with a convertible protection mode, which can not only detect the fault current and voltage of the ground wire, but also charge the ground wire for detecting the fault current and voltage of the ground wire The protection function is selectively converted, which not only solves the problem that the leakage protection plug cannot be used normally due to false tripping, but also reduces the after-sales maintenance rate and maintenance cost of the product.

The technical solution proposed by the present invention is as follows:

A leakage protection plug with a convertible protection mode, including a shell, a pin, a first phase wire and a second phase wire, a first neutral wire and a second neutral wire, a first ground wire and a second ground wire, the first The zero-sequence current transformer through which the 2 phase lines and the 2nd neutral line pass, the test circuit, the electromagnetic tripping and locking device, the electromagnetic tripping and locking device consists of an electromagnetic coil and its driving circuit, a phase line contact switch , zero line contact switch, and ground line contact switch. The driving circuit of the electromagnetic coil is mainly composed of the first rectifier bridge, the first thyristor, the first resistor, and the first amplifying circuit. The zero sequence current mutual inductance One output end and the other output end of the secondary winding of the device are respectively connected in parallel with the first input end and the second input end of the first amplifying circuit, and a ground wire fault current detection circuit and a ground wire fault voltage detection circuit are also provided , the first transfer switch, the second transfer switch, a one-way conduction circuit; the ground wire fault current detection circuit is provided with a ground wire live detection sensor, a second thyristor, and a second amplifying circuit, and the ground wire fault The voltage detection circuit is provided with a first capacitor, a second rectifier bridge, a third resistance-capacitance element, a photocoupler, a fourth resistor, a first triode, and a fifth resistor, and one end of the first resistor is connected to the positive pole of the DC output end of the first rectifier bridge , the first thyristor anode and the second thyristor anode are connected, the other end of the first resistor is connected to the power end of the first amplifying circuit, the power end of the second amplifying circuit, and the third pin end of the first changeover switch, the second The ground terminal of the 1st amplifying circuit, the grounding terminal of the 2nd amplifying circuit, the cathode of the first thyristor, the cathode of the second thyristor are connected to the negative pole of the DC output terminal of the first rectifier bridge, the trigger output terminal of the first amplifying circuit is connected to the first The SCR trigger pole is connected; the second ground wire passes through the ground wire electrification detection sensor, and the other output terminal of the secondary winding of the ground wire electrification detection sensor is connected to the second input end of the second amplifier circuit, and the ground wire electrification detection The first output end of the secondary winding of the sensor is connected to the third pin end of the second changeover switch, the first foot end of the second changeover switch is connected to the first input end of the second amplifying circuit, and the trigger output end of the second amplifying circuit is connected to the second end of the second amplifying circuit. The thyristor control pole is connected; the loop formed by the first capacitor, the AC input end of the second rectifier bridge, and the third resistance-capacitance element in series is connected between the first ground line and the first neutral line , the DC output terminal of the second rectifier bridge is connected in parallel with the input terminal of the photocoupler, the output terminal of the photocoupler, the collector of the first triode are connected with the second pin of the first transfer switch, and the other output terminal of the photocoupler Connect with one end of the fourth resistor and the base of the first transistor, connect the emitter of the first transistor with one end of the fifth resistor, connect the other end of the fifth resistor, the other end of the fourth resistor and the negative pole of the DC output terminal of the first rectifier bridge, unidirectional conduction The input end of the circuit is connected with the emitter of the first triode and one end of the fifth resistor, the output end of the unidirectional conduction circuit is connected with the third intermediate input end of the first amplifying circuit, and the first changeover switch is connected with the second changeover switch linkage on or off.

There is also a second resistor and a light-emitting diode, one end of the second resistor is connected to the second pin of the first transfer switch, the other end of the second resistor is connected to the positive pole of the light-emitting diode, and the negative pole of the light-emitting diode is connected to the negative pole of the DC output terminal of the first rectifier bridge .

The first transfer switch and the second transfer switch are integrally installed on the bottom case of the housing.

The light-emitting diodes are installed on the surface shell of the housing.

The unidirectional conduction circuit is composed of a first diode.

The one-way conduction circuit is formed by the second triode.

The third resistance-capacitance element is composed of a resistor.

The third resistance-capacitance element is composed of a capacitor.

The third resistance-capacitance element is composed of a resistor and a capacitor.

Compared with prior art, the present invention has following remarkable effect:

(1) The leakage protection plug with convertible protection mode of the present invention can detect the fault current of the ground wire, and once the fault current of the ground wire unexpectedly reaches a predetermined threshold, it can immediately switch off the phase, zero, and ground wires. The head switches are all disconnected, so the present invention provides a safer electricity use safety guarantee than the existing leakage protection plug.

(2) The leakage protection plug of the present invention can also detect the fault voltage of the ground wire. Once the fault voltage of the ground wire unexpectedly reaches a predetermined threshold, it can immediately switch the phase, zero, and ground wires before people get an electric shock. The contact switches are all disconnected, so the present invention provides a safer electricity use safety guarantee than the existing leakage protection plug.

(3) The leakage protection plug of the present invention can select different charging protection modes to the ground wire through two transfer switches, so that a suitable ground wire charging protection mode can be selected for a specific power consumption environment, which solves the problem of existing The leakage protection plug cannot be used normally due to false tripping, which also reduces the after-sales maintenance rate and maintenance cost of the product.

The leakage protection plug with switchable protection mode of the present invention is mainly used in the leakage protection of various household appliances, and is mainly made into a power cord with a leakage protection plug.

Description of drawings

Fig. 1 is a schematic circuit diagram of a leakage protection plug of a switchable protection mode according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of another alternative to the unidirectional conduction circuit 30 shown in FIG. 1 .

Detailed ways

The present invention is described in further detail by the following examples.

As shown in Figure 1, a leakage protection plug with a convertible protection mode includes a shell, a pin, a first phase line 1 and a second phase line 4, a first neutral line 2 and a second neutral line 5, and a first ground Line 3 and the second ground wire 6, the zero-sequence current transformer 17 through which the second phase line 4 and the second zero line 5 both pass, the test circuit 12, the electromagnetic tripping and locking device, the electromagnetic tripping and The locking device is composed of an electromagnetic coil 13 and its drive circuit, a phase line contact switch 7, a neutral line contact switch 8, and a ground line contact switch 9. The drive circuit of the electromagnetic coil 13 is mainly composed of the first rectifier bridge 14, The first thyristor 15, the first resistor 10, and the first amplifying circuit 16 are composed of one output end and the other output end of the secondary winding of the zero-sequence current transformer 17 and the first amplifying circuit 16 respectively. The 1st input terminal 16-1 and the 2nd input terminal 16-2 are connected in parallel. A ground fault current detection circuit, a ground fault voltage detection circuit, a first transfer switch 26 - 1 , a second transfer switch 26 - 2 , and a one-way conduction circuit 30 are also provided. The ground wire fault current detection circuit is provided with a ground wire electrification detection inductor 18 , a second thyristor 27 , and a second amplifying circuit 11 . The ground fault voltage detection circuit is provided with a first capacitor 19 , a second bridge rectifier 20 , a third resistance-capacitance element 21 , a photocoupler 22 , a fourth resistor 23 , a first triode 24 and a fifth resistor 25 . One end of the first resistor 10 is connected to the positive pole of the DC output terminal of the first rectifier bridge 14, the anode of the first thyristor 15, and the anode of the second thyristor 27, and the other end of the first resistor 10 is connected to the power supply terminal Vs1 of the first amplifying circuit 16, The power supply end Vs2 of the 2nd amplifying circuit 11, the 3rd pin end 26-1-3 of the 1st transfer switch 26-1 are connected, the ground end GND1 of the 1st amplifying circuit 16, the ground end GND2 of the 2nd amplifying circuit 11, the The cathode of the first thyristor 15 and the cathode of the second thyristor 27 are respectively connected to the negative pole of the DC output terminal of the first rectifier bridge 14, and the trigger output terminal of the first amplifying circuit 16 is connected to the control pole of the first thyristor 15. The second ground wire 6 passes through the ground wire electrification detection sensor 18, and the other output end of the secondary winding of the ground wire electrification detection inductor 18 is connected to the second input end 11-2 of the second amplifier circuit 11, and the ground wire electrification detection An output end of the secondary winding of the inductor 18 is connected to the third pin end 26-2-3 of the second transfer switch 26-2, and the first pin end 26-2-1 of the second transfer switch 26-2 is connected to the second amplifying The first input terminal 11-1 of the circuit 11 is connected, and the trigger output terminal of the second amplifying circuit 11 is connected with the control electrode of the second thyristor 27 . The loop formed by the first capacitor 19, the AC input end of the second rectifier bridge 20, and the third resistance-capacitance element 21 in series is connected between the first ground wire 3 and the first neutral wire 2. 2. The DC output terminal of the rectifier bridge 20 is connected in parallel with the input terminal of the photocoupler 22, the output terminal of the photocoupler 22, the collector of the first triode 24 and the second pin terminal 26-1- of the first transfer switch 26-1 2 connections, the other output end of the photocoupler 22 is connected to one end of the fourth resistor 23 and the base of the first triode 24, the emitter of the first triode 24 is connected to one end of the fifth resistor 25, the other end of the fifth resistor 25, the fourth resistor The other end of 23 is connected to the negative pole of the DC output end of the first rectifier bridge 14 . The input terminal Vi1 of the unidirectional conduction circuit 30 is connected to the emitter of the first transistor 24 and one end of the fifth resistor 25 , and the output terminal Vo1 of the unidirectional conduction circuit 30 is connected to the third intermediate input terminal 16 - 3 of the first amplifying circuit 16 . The first transfer switch 26-1 is turned on or off in linkage with the second transfer switch 26-2.

The present invention can also be provided with the 2nd resistance 29 and light-emitting diode 28 in the collector loop of the 1st triode 24, as shown in Figure 1, the 2nd resistance 29 one end and the 2nd pin end of the 1st transfer switch 26-1 26-1-2 connection, the other end of the second resistor 29 is connected to the anode of the LED 28, and the cathode of the LED 28 is connected to the cathode of the DC output terminal of the first rectifier bridge 14. The light-emitting diodes 28 are installed on the face shell of the housing.

In this embodiment, the first transfer switch 26-1 and the second transfer switch 26-2 are integrated and installed on the bottom case of the housing.

In this embodiment, the unidirectional conduction circuit 30 is composed of a first diode 30-1. As shown in Figure 2, the unidirectional conduction circuit 30 can also be composed of the second triode 30-2. At this time, the base of the second triode 30-2 is directly connected to the input terminal Vi1 of the unidirectional conduction circuit 30, and the second triode The emitter of 30-2 is directly connected to the output terminal Vo1 of the unidirectional conduction circuit 30, and the collector of the second triode 30-2 is connected to the second pin 26-1-2 of the first transfer switch 26-1.

In this embodiment, the third resistance-capacitance element 21 is composed of a resistor, and may also be composed of a capacitor or a combination of a resistor and a capacitor.

During use, the leakage protection plug reset button is pressed, and the phase line contact switch 7, the neutral line contact switch 8, and the ground line contact switch 9 are closed to connect the mains power supply to provide working power for the electrical appliances at the lower end.

In use, if the insulation of the electrical appliance is damaged to generate leakage, the zero-sequence current transformer 17 detects the leakage signal and inputs the signal to the first input terminal 16-1 and the second input terminal 16-1 of the first amplifying circuit 16. 2. When the leakage current reaches the predetermined threshold value, the output signal of the first amplifying circuit 16 triggers the conduction of the first thyristor 15 to make the electromagnetic coil 13 work and connect the phase line contact switch 7, the neutral line contact switch 8, and the ground wire The contact switches 9 are all disconnected immediately, thereby ensuring people's electricity safety.

If the leakage protection plug of the present invention selects in advance that the second changeover switch 26-2 and the first changeover switch 26-1 are connected to the ground fault current protection mode according to the use environment, the first pin end of the second changeover switch 26-2 Connect between 26-2-1 and the 3rd pin end 26-2-3 of the 2nd transfer switch 26-2, the 2nd pin end 26-2-2 of the 2nd transfer switch 26-2 and the 2nd transfer switch 26 -2 is disconnected between the 3rd pin end 26-2-3, at the same time, due to the linkage action between the 1st transfer switch 26-1 and the 2nd transfer switch 26-2, so, the 1st transfer switch 26-1 Also connected between the 1st pin end 26-1-1 of the 1st transfer switch 26-1 and the 3rd pin end 26-1-3 of the 1st changeover switch 26-1, the 2nd pin end 26-1-1 of the 1st changeover switch 26-1 2 and the third pin 26-1-3 of the first transfer switch 26-1 are also disconnected, and the light emitting diode 28 is in a extinguished state, indicating that the leakage protection plug is in the ground fault current protection mode. When an abnormality in the grounding system causes the first ground wire 3 and the second ground wire 6 to be electrified accidentally, the ground wire electrification detection sensor 18 on the ground wire fault current detection circuit immediately detects the fault current flowing through the second ground wire 6 and Send the signal to the first input terminal 11-1 and the second input terminal 11-2 of the second amplifying circuit 11, when the detected ground fault current is greater than the predetermined current threshold, the second amplifying circuit 11 outputs a signal to trigger The second thyristor 27 is turned on to make the electromagnetic coil 13 work, and all the phase line contact switch 7, the neutral line contact switch 8, and the ground line contact switch 9 are all disconnected immediately, thereby better ensuring people's electricity safety .

If the leakage protection plug of the present invention selects in advance that the first transfer switch 26-1 and the second transfer switch 26-2 are connected to the ground fault voltage protection mode according to the use environment, the first pin end of the first transfer switch 26-1 26-1-1 and the 3rd pin end 26-1-3 of the 1st changeover switch 26-1 are disconnected, the 2nd pin end 26-1-2 of the 1st changeover switch 26-1 is connected with the 1st changeover switch 26 -1 is connected between the 3rd pin end 26-1-3, and the light-emitting diode 28 lights up to indicate that the leakage protection plug is in the ground fault voltage protection mode. Linkage action between the switch 26-2, so, also break between the 1st pin end 26-2-1 of the 2nd transfer switch 26-2 and the 3rd pin end 26-2-3 of the 2nd transfer switch 26-2 Open, also connected between the 2nd pin end 26-2-2 of the 2nd changeover switch 26-2 and the 3rd pin end 26-2-3 of the 2nd changeover switch 26-2. When an abnormality occurs in the grounding system and the first ground wire 3 and the second ground wire 6 are accidentally electrified, the photocoupler 22 on the ground fault voltage detection circuit outputs a signal to the first triode 24. When the detected ground fault voltage is greater than When the predetermined voltage threshold is reached, the first triode 24 outputs a high-level signal to the anode of the first diode 30-1 of the one-way conduction circuit 30 to make it conduct and send the signal to the third intermediate input of the first amplifying circuit 16 The terminal 16-3 further makes the output signal of the first amplifying circuit 16 trigger the conduction of the first thyristor 15 to make the electromagnetic coil 13 work, and all the phase line contact switch 7, the neutral line contact switch 8, and the ground line contact switch 9 are all immediately Disconnect, so as to better protect people's electricity safety.

Claims (9)

1. the leakage protecting plug of a convertible protected mode, include shell, latch, 1st phase line and the 2nd phase line, 1st zero line and the 2nd zero line, 1st ground wire and the 2nd ground wire, the zero sequence current mutual inductor that described 2nd phase line and the 2nd zero line all pass, test loop, electromagnetic trip and locker, this electromagnetic trip and locker are by solenoid and drive circuit thereof, phase line switch contacts, zero line switch contacts, ground wire switch contacts forms, the drive circuit of described solenoid is primarily of the 1st rectifier bridge, 1st controllable silicon, 1st resistance, 1st amplifying circuit composition, one output of described zero sequence current mutual inductor secondary winding and another output are connected in parallel with the 1st input of described 1st amplifying circuit and the 2nd input respectively, it is characterized in that: be also provided with ground wire fault current detection circuit, ground wire false voltage testing circuit, 1st change over switch, 2nd change over switch, one-way conduction circuit, described ground wire fault current detection circuit is provided with ground wire electrified detection inductor, the 2nd controllable silicon, the 2nd amplifying circuit, and described ground wire false voltage testing circuit is provided with the 1st electric capacity, the 2nd rectifier bridge, the 3rd Resistor-Capacitor Unit, photoelectrical coupler, the 4th resistance, the 1st triode, the 5th resistance, 1st resistance one end is connected with the 1st rectifier bridge DC output end positive pole, the 1st controllable silicon anode, the 2nd controllable silicon anode, the power end of the 1st resistance other end and the 1st amplifying circuit, the power end of the 2nd amplifying circuit, the 3rd foot of the 1st change over switch are connected, the ground end of the 1st amplifying circuit, the ground end of the 2nd amplifying circuit, the 1st controllable silicon negative electrode, the 2nd controllable silicon negative electrode are connected with the 1st rectifier bridge DC output end negative pole, and the trigger output end of the 1st amplifying circuit is connected with the 1st SCR control pole, described 2nd ground wire is through ground wire electrified detection inductor, another output of ground wire electrified detection inductor secondary winding is connected with the 2nd amplifying circuit the 2nd input, ground wire electrified detection inductor secondary winding one output is connected with the 3rd foot of the 2nd change over switch, 1st foot of the 2nd change over switch is connected with the 2nd amplifying circuit the 1st input, and the 2nd amplifying circuit trigger output end is connected with the 2nd control machines pole, by described 1st electric capacity, the ac input end of the 2nd rectifier bridge, the loop that 3rd Resistor-Capacitor Unit is in series successively is connected between the 1st described ground wire and the 1st zero line, the DC output end of the 2nd rectifier bridge and the input of photoelectrical coupler are connected in parallel, photoelectrical coupler one output, 1st transistor collector is connected with the 2nd foot of the 1st change over switch, another output of photoelectrical coupler and the 4th resistance one end, 1st transistor base connects, 1st transistor emitter is connected with the 5th resistance one end, the 5th resistance other end, the 4th resistance other end is connected with the 1st rectifier bridge DC output end negative pole, the input of one-way conduction circuit and the 1st transistor emitter, 5th resistance one end connects, the output of one-way conduction circuit is connected with the 3rd intermediate input of the 1st amplifying circuit, described 1st change over switch and described 2nd change over switch link and open or close.

2. the leakage protecting plug of convertible protected mode according to claim 1, is characterized in that: be also provided with the 2nd resistance and light-emitting diode; 2nd resistance one end is connected with the 2nd foot of the 1st change over switch, and the 2nd resistance other end is connected with light-emitting diode positive pole, and light-emitting diode negative pole is connected with the 1st rectifier bridge DC output end negative pole.

3. the leakage protecting plug of convertible protected mode according to claim 1, is characterized in that: on described 1st change over switch and the integrated drain pan being arranged on described shell of the 2nd change over switch.

4. the leakage protecting plug of convertible protected mode according to claim 2, is characterized in that: described light-emitting diode is arranged on the face-piece of described shell.

5. the leakage protecting plug of convertible protected mode according to claim 1, is characterized in that: described one-way conduction circuit is made up of the 1st diode.

6. the leakage protecting plug of convertible protected mode according to claim 1, is characterized in that: described one-way conduction circuit is made up of the 2nd triode.

7. the leakage protecting plug of convertible protected mode according to claim 1, is characterized in that: described 3rd Resistor-Capacitor Unit is made up of resistance.

8. the leakage protecting plug of convertible protected mode according to claim 1, is characterized in that: described 3rd Resistor-Capacitor Unit is made up of electric capacity.

9. the leakage protecting plug of convertible protected mode according to claim 1, is characterized in that: described 3rd Resistor-Capacitor Unit is made up of the assembly of resistance and electric capacity.