CN201256127Y - High price/performance ratio DC contactor - Google Patents

Abstract

The utility model relates to a DC contactor with high cost-performance ratio, which comprises a voltage dependent resistor, a single-phase AC contactor coil, a single-phase AC contactor main contact, a small scale DC relay coil, a small scale DC relay normally opened contact, a small scale DC relay normally closed contact, a single-phase AC contactor coil current limiting resistor, a delay motion capacitance and a capacitor current limiting resistor. By utilizing the single-phase AC contactor to replace a DC contactor with the same capacity, using the voltage dependent resistor to limit electric arc voltage when two ends of the contact are broken, electric arc power is reduced when the contactor is broken, thereby arc-less breaking is realized, further, by utilizing the scheme of connecting the coil with the resistors in series to reduce current in holding state, energy can be greatly saved, thereby having the advantages of low cost, long service life, saving energy and the like.

Description

Cost-effective DC contactor

Technical field

The utility model relates to a direct current contactor with high cost performance.

Background technique

The Chinese utility model patent "intelligent hybrid DC contactor" with the patent number of 01272976.0 is an intelligent DC contactor controlled by a single-chip microcomputer invented by Zhang Peiming and others of Fuzhou University. High performance indicators such as breaking, small operating pressure drop, and high working reliability. In addition, the Chinese patent "DC electronic arc extinguisher" with the patent number 200420003021.0 applied by Zhang Yueren and others also uses the parallel connection of IGBT and main contact to achieve the purpose of arc suppression, and the parallel connection of the varistor is to protect the IGBT. , not directly used for main contact arc suppression. However, the above-mentioned devices all have problems such as high cost, complex structure, and high energy consumption in operation, and cannot be applied to general applications that require low cost and high performance indicators, especially considering the difference between AC contactors and DC contactors. The cost varies greatly, and when the DC contactor breaks the DC circuit, a strong arc is generated, which consumes a lot of energy during operation, so there is no better technical solution to solve the above problems.

Utility model content

The purpose of the utility model is to provide a DC contactor with high cost performance, which is beneficial to greatly reduce the cost, prolong the service life and save energy consumption.

In order to achieve the above object, the technical solution of the utility model is constituted as follows: it includes a varistor, a single-phase AC contactor coil, a single-phase AC contactor main contact, a small DC relay coil, a small DC relay normally open contact, Small DC relay normally closed contacts, single-phase AC contactor coil current-limiting resistor, time-delay action capacitor and capacitor current-limiting resistor; One end of the normally open contact of the DC relay, one end of the main contact of the single-phase AC contactor and one end of the control switch are connected, and the other end of the control switch is connected to one end of the capacitor current limiting resistor, one end of the small DC relay coil, and One end of the AC contactor coil current-limiting resistor is connected to one end of the normally closed contact of the small DC relay, the other end of the normally open contact of the small DC relay is connected to one end of the varistor, and the other end of the varistor is connected to the single-phase The other end of the main contact of the AC contactor is connected and then connected to one end of the load. The other end of the current limiting resistor of the coil of the single-phase AC contactor is connected to the other end of the normally closed contact of the small DC relay, and then connected to the single-phase AC contactor. One end of the phase AC contactor coil, the other end of the capacitor current-limiting resistor is connected to one end of the delay action capacitor, the other end of the delay action capacitor is connected to the other end of the small DC relay coil, and then connected to the single-phase AC contactor The other end of the coil and the other end of the load, and finally connected to the negative end of the power supply.

Since the AC current crosses zero, and because the inductive load will generate a high overvoltage when breaking the DC circuit, it is easier to break the arc of the breaking current than the DC circuit of the same capacity. DC contactors cost much less. However, if a single-phase AC contactor is used instead of the same-capacity DC contactor, the problem of arc extinguishing must be solved. The utility model uses a piezoresistor to limit the arc voltage when the two ends of the contact are broken, thereby reducing the arc energy when the contactor is broken. In the case of using an AC contactor, less arc breaking is still achieved, and the varistor voltage of the varistor can be slightly higher than or lower than the power supply voltage. The DC contactor consumes the same energy in the switching process as in the holding state. In order to reduce the energy loss in the holding state, the utility model adopts the scheme of reducing the current by connecting the coils in series with the resistance in the holding state to achieve substantial energy saving.

Therefore, compared with the prior art, the utility model has significant advantages such as low cost, long life, energy saving, simple structure, etc., and can be applied to various application occasions requiring very low cost and high performance index.

Description of drawings

Fig. 1 is a schematic block diagram of the structure of the utility model.

Explanation of the symbols in the figure: Y is the piezoresistor, K is the coil of the single-phase AC contactor, K1 is the main contact of the single-phase AC contactor, J is the coil of the small DC relay, J1 is the normally open contact of the small DC relay, and J2 is the Small DC relay normally closed contact, R is the single-phase AC contactor coil current limiting resistor, C is the delay action capacitor, R1 is the capacitor current limiting resistor, A is the control switch, D1 is the positive terminal of the power supply, D2 is the negative terminal of the power supply .

Detailed ways

Below in conjunction with accompanying drawing of description and specific embodiment, the utility model content is described in detail:

As shown in Figure 1, the cost-effective DC contactor of the utility model includes a varistor Y, a single-phase AC contactor coil K, a single-phase AC contactor main contact K1, a small DC relay coil J, and a small DC relay normally open Contact J1, small DC relay normally closed contact J2, single-phase AC contactor coil current limiting resistor R, delay action capacitor C and capacitor current limiting resistor R1;

The circuit connection relationship between the above components and the power supply, control switch A and load L is as follows: the positive terminal D1 of the power supply is connected to one end of the normally open contact J1 of the small DC relay, one end of the main contact K1 of the single-phase AC contactor and the control switch A One end of the control switch A is connected to one end of the current limiting resistor R1 of the capacitor, one end of the coil J of the small DC relay, one end of the current limiting resistor R of the coil of the single-phase AC contactor and the normally closed contact J2 of the small DC relay. One end of the small DC relay normally open contact J1 is connected to one end of the varistor Y, and the other end of the varistor Y is connected to the other end of the main contact K1 of the single-phase AC contactor. Connected to one end of the load L, the other end of the single-phase AC contactor coil current-limiting resistor R is connected to the other end of the small DC relay normally closed contact J2, and then connected to one end of the single-phase AC contactor coil K, the capacitor The other end of the current-limiting resistor R1 is connected to one end of the delay action capacitor C, and the other end of the delay action capacitor C is connected to the other end of the small DC relay coil J, and then connected to the other end of the single-phase AC contactor coil K One end and the other end of the load L, and finally connected to the negative terminal D2 of the power supply.

The working process of the above-mentioned cost-effective DC contactor of the utility model is as follows:

When the control switch A is closed and the contactor is turned on, the coil K of the single-phase AC contactor is energized, and the contactor is in a strong excitation state. Due to the delay action capacitor C has a charging process, the coil J of the small DC relay is excited with a delay, and the small DC relay Delay pull-in, after the main contact K1 of the single-phase AC contactor is closed, the normally closed contact J2 of the small DC relay is opened, and the current-limiting resistor R of the coil of the single-phase AC contactor is connected in series with the coil K circuit of the single-phase AC contactor to ensure In the holding state of the contactor, the contactor runs energy-saving, then the normally open contact J1 of the small DC relay is closed, and the varistor Y is connected to the circuit to complete the connection process;

When the circuit needs to be broken, the control switch A is turned on, and the coil K of the single-phase AC contactor is powered off. Due to the delay action, the charge on the capacitor C is released to the coil J of the small DC relay, and the coil J of the small DC relay delays the power-off. The DC relay is released after a delay, and after the main contact K1 of the single-phase AC contactor is opened, when the voltage at the two terminals of the main contact K1 of the single-phase AC contactor exceeds the varistor voltage of the varistor Y, the varistor Y acts, and the single-phase AC contactor turns on. The voltage of the main contact K1 of the phase AC contactor is limited to a certain voltage value, and the arc energy is very small. After the main contact K1 of the single-phase AC contactor and the normally open contact J1 of the small DC relay are both opened, the main circuit is completely disconnected. Ensure that the main contact K1 of the single-phase AC contactor is less worn, the normally closed contact J2 of the small DC relay is closed during the process, and the contactor returns to the state before it was turned on.

Claims (1)

1. the D.C. contactor of a high performance-price ratio, it is characterized in that: it comprises piezo-resistance (Y), single phase alternating current (A.C.) contactor coil (K), single phase alternating current (A.C.) main noddle on contactor (K1), small-sized DC relay coil (J), small-sized DC relay normally open contact (J1), small-sized DC relay normally closed interlock (J2), single phase alternating current (A.C.) contactor coil current-limiting resistance (R), deferred action electric capacity (C) and capacitor current-limiting resistance (R1);

Above-mentioned each parts and power supply, the circuit connecting relation of control switch (A) and load (L) is as follows: power positive end (D1) respectively with an end of small-sized DC relay normally open contact (J1), one end of one end of single phase alternating current (A.C.) main noddle on contactor (K1) and control switch (A) joins, the other end of control switch (A) respectively with an end of capacitor current-limiting resistance (R1), one end of small-sized DC relay coil (J), one end of one end of single phase alternating current (A.C.) contactor coil current-limiting resistance (R) and small-sized DC relay normally closed interlock (J2) joins, one end of the other end of small-sized DC relay normally open contact (J1) and piezo-resistance (Y) joins, after joining, receives the other end of the other end of piezo-resistance (Y) and single phase alternating current (A.C.) main noddle on contactor (K1) end of load (L) again, after the other end of the other end of single phase alternating current (A.C.) contactor coil current-limiting resistance (R) and small-sized DC relay normally closed interlock (J2) joins, receive an end of single phase alternating current (A.C.) contactor coil (K) again, the other end of capacitor current-limiting resistance (R1) is received an end of deferred action electric capacity (C), after the other end of the other end of deferred action electric capacity (C) and small-sized DC relay coil (J) joins, receive the other end of single phase alternating current (A.C.) contactor coil (K) and the other end of load (L) again, receive power supply negative terminal (D2) at last again.