CN204967247U - Switch contact adhesion fault protection circuit - Google Patents

Abstract

The utility model provides a switch contact adhesion fault protection circuit, includes: connect toward electric network source's leakage protection switch, by the input connection of protection switch main circuit in the output of leakage protection switch main circuit, connect toward the load by the output of protection switch main circuit, connect toward a tie point warp control switch and an impedance ground connection of load, including making break off the then control circuit of another switch -on by protection switch and control switch one of which. The adhesion in case the emergence is contacted by protection switch, this circuit can cut off power supply rapidly to the electrical safety of protection personnel, equipment.

Description

A kind of switch contact adhesion fault protective circuit

Technical field

The utility model relates to the protective circuit to low voltage switch fault, particularly relates to the protective circuit to switch contact adhesion fault, in International Patent Classification (IPC), can belong to H02H3/00.

Background technology

As recently reported the problem that the charging of electric automobile vehicle mounted electric pond occurs, contact adhesion can be there is because of reasons such as environment, aging and excess loads in low voltage switch, and once occur, namely cause Systematical control lost efficacy or buried potential safety hazard, especially easily the accidents such as electric shock occur.Although the prior art disclosed as CN2348517Y, CN102751695A, CN203135386U and CN202949212U etc. for as described in designed by problem has, circuit structure is complicated and cost is higher and reliability is on the low side.

Summary of the invention

Technical problem to be solved in the utility model is: propose a kind of switch contact adhesion fault protective circuit, effectively can solve problem described in background technology and cost is lower and reliability is higher.

The technical scheme that the utility model solve the technical problem is: a kind of switch contact adhesion fault protective circuit, comprising: the earth leakage circuit-breaker being access to electric network source; The input of protected switch main circuit is connected to the output of described earth leakage circuit-breaker main circuit; The output of protected switch main circuit is access to load; The described tie point being access to load is through a control switch and an impedance earth; Comprise and make described protected switch and control switch one disconnect then another control circuit connected.

Control circuit at protected switch once occur contact fault adhesion and instruction its disconnect; the output of namely connecting main circuit of described control switch is through the loop of control switch and impedance earth; cause earth leakage circuit-breaker action and cut off rapidly power supply, thus the Electrical Safety of protection personnel, equipment.

This technical scheme utilizes usual the be provided with earth leakage circuit-breaker of power consumption equipment dexterously; it is made to produce leakage current in case of a fault and action because of designed control circuit; thus have protected switch contact adhesion fault defencive function concurrently and reduce costs, circuit obviously simply and very reliable.

The program can be designed specifically to:

---described protected switch is master control contactor K1, and described control switch is relay K 2, and described impedance is leak resistance R0, and master control contactor K1 main circuit exports with the tie point of load through the make contact of relay K 2 and leak resistance R0 ground connection;

---in described control circuit, the base stage of triode Q1 connects single-chip microcomputer one I/O port through resistance R1, and this I/O port, when master control contactor K1 connects, exports high level drive singal; The base stage of the collector connecting transistor Q2 of triode Q1, the collector electrode of triode Q1 meets DC power supply VCC through resistance R3, the base stage of triode Q1 and emitter cross-over connection resistance R2, the base stage of triode Q2 and emitter cross-over connection resistance R4 and electric capacity C1, triode Q2 collector electrode meets DC power supply VCC through the coil of relay K 2, the grounded emitter of triode Q1, Q2.

This design further by power consumption equipment as more complicated in electric automobile vehicle mounted electric pond charging pile etc. etc. usual based on the single-chip microcomputer with multi-control function that is provided with, thus reduce the complexity of circuit, and thus reduce costs and improve reliability.

The technical solution of the utility model and effect will be further described in a specific embodiment by reference to the accompanying drawings.

Accompanying drawing explanation

Fig. 1 is the utility model embodiment fault secure circuit schematic diagram.

Embodiment

As shown in Figure 1, to the utility model embodiment fault secure circuit this circuit improve to form on the basis of as usual in power consumption equipments such as electric automobile vehicle mounted electric pond charging piles the circuit had, and its structure comprises:

---the earth leakage protective air switch QF of the band that power consumption equipment has had usually, master control contactor K1 and control circuit thereof, this control circuit is equipped with single-chip microprocessor MCU usually, master control contactor K1 according to MCU I/O port given by signalizing activity, be switched on or switched off be connected to master control contactor K1 main circuit export charging pile load RL;

---for the formation of the leak resistance R0 of leakage current, master control contactor K1 main circuit exports with the tie point of charging pile load RL through the make contact of relay K 2 and leak resistance R0 ground connection;

---containing in the control circuit of single-chip microprocessor MCU, the base stage of triode Q1 connects single-chip microprocessor MCU one I/O port through resistance R1, and this I/O port, when master control contactor K1 connects, exports high level drive singal; The base stage of the collector connecting transistor Q2 of triode Q1, the collector electrode of triode Q1 meets DC power supply VCC through resistance R3, the base stage of triode Q1 and emitter cross-over connection resistance R2, the base stage of triode Q2 and emitter cross-over connection resistance R4 and electric capacity C1, triode Q2 collector electrode meets DC power supply VCC through the coil of relay K 2, these coil two ends are in parallel for absorbing superpotential diode D1, the grounded emitter of triode Q1, Q2.

Under normal circumstances, when charging pile is in charged state, master control contactor K1 main circuit is connected and the make contact of relay K 2 disconnects; When charging pile is in holding state, master control contactor K1 main circuit disconnects and the make contact of relay K 2 is connected.Once adhesion appears in master control contactor K1 main circuit contact, namely the make contact of master control contactor K1 main circuit and relay switch K2 occurs situation about simultaneously connecting unexpectedly making control circuit cut off power supply rapidly.Operation principle is as follows:

---when charging pile load RL is energized, master control contactor K1 action, its main circuit is connected, triode Q1 base stage obtains the high level driving voltage of the I/O port from single-chip microprocessor MCU immediately, therefore triode Q1 conducting, and triode Q2 ends, the coil no current of relay K 2 passes through, relay K 2 is failure to actuate, and its make contact disconnects, and leak resistance R0 branch road passes through without the electric current from major loop;

---when charging pile load RL is standby, master control contactor K1 resets, its main circuit disconnects, driving voltage from the I/O port of single-chip microprocessor MCU reverts to low level, therefore triode Q1 ends, triode Q2 conducting, the coil electricity action of relay K 2, although its make contact is connected, leak resistance R0 branch road passes through because main circuit disconnects no current;

---when master control contactor K1 there is contact adhesion and can not disconnect and charging pile load RL is in holding state time; then triode Q2 conducting; the coil electricity action of relay K 2; its make contact is connected; the line voltage connected of main circuit through this make contact and leak resistance R0 leakage current to greatly; thus make the earth leakage protective air switch QF of band trip, cut off main circuit power supply power supply.

Fig. 1 circuit belongs to modular design, can optionally adjust.Such as, the coil of master control contactor and relay K 2 can be same or directly or through power circuit drive with characteristic I/O port by single-chip microprocessor MCU, and change former for relay K 2 make contact into break contact.Now can cancel each electronic circuit shown in former Fig. 1, but the competition requirement of master control contactor and relay contact need be appraised and decided.

Claims (2)

1. a switch contact adhesion fault protective circuit, comprising:

---be access to the earth leakage circuit-breaker of electric network source;

---the input of protected switch main circuit is connected to the output of described earth leakage circuit-breaker main circuit;

---the output of protected switch main circuit is access to load;

It is characterized in that:

---described in be access to the tie point of load through a control switch and an impedance earth;

---comprise and make described protected switch and control switch one disconnect then another control circuit connected.

2. fault secure circuit according to claim 1, is characterized in that:

---described protected switch is master control contactor K1, and described control switch is relay K 2, and described impedance is leak resistance R0, and master control contactor K1 main circuit exports with the tie point of load through the make contact of relay K 2 and leak resistance R0 ground connection;

---in described control circuit, the base stage of triode Q1 connects single-chip microcomputer one I/O port through resistance R1, and this I/O port, when master control contactor K1 connects, exports high level drive singal; The base stage of the collector connecting transistor Q2 of triode Q1, the collector electrode of triode Q1 meets DC power supply VCC through resistance R3, the base stage of triode Q1 and emitter cross-over connection resistance R2, the base stage of triode Q2 and emitter cross-over connection resistance R4 and electric capacity C1, triode Q2 collector electrode meets DC power supply VCC through the coil of relay K 2, the grounded emitter of triode Q1, Q2.