CN106098472B - And the pulse A.C. contactor of transient voltage can be restrained - Google Patents

Abstract

The invention discloses a single-pulse AC contactor capable of suppressing transient voltage, which comprises a moving contact MC, a normally closed contact NC, a normally open contact NO, a moving iron core M, a static iron core G, and a return spring F. Two parts, the conventional AC contactor and the electronic unit 100 composed of the excitation coil L, are characterized in that the electronic unit 100 is composed of a transient voltage suppression diode TVS, an AC-DC conversion circuit 101, and a single pulse generating circuit 102 , a switch circuit 103, a bridge circuit 104, and a step-down circuit 105.

Description

Single-pulse AC contactor capable of suppressing transient voltage

technical field

The invention relates to the field of low-voltage electrical appliances, in particular to a "single-pulse AC contactor capable of suppressing transient voltage" which is controlled by a single pulse, can save electricity efficiently, and has the function of suppressing transient voltage.

Background technique

Alternating Current Contactor (Alternating Current Contactor) is a low-voltage electrical appliance that is widely used. As of 2015, there are more than one billion AC contactors running online in my country, and the number is increasing at an annual rate of 80 million. Its working principle is to use the electromagnet to drive the movable contact to separate or close the normally closed contact or normally open contact, so as to cut off or connect the circuit. It is suitable for starting or controlling three-phase induction motors and other electrical equipment.

Figure 1 is a working principle diagram of a conventional AC contactor. This conventional AC contactor is mainly composed of a moving iron core, a static iron core, an excitation coil, a return spring, a moving contact, a normally closed contact, and a normally open contact. When the excitation coil is connected to AC220V, AC110V or AC380V voltage (hereinafter referred to as AC220V, AC110V or AC380V as AC voltage or excitation power supply), the moving iron core is closed to the static iron core by the magnetic force generated by the excitation coil, and is connected to the moving iron core. The linked moving contact is also closed with the normally open contact, and the external circuit is connected through the normally open contact; when the AC voltage on the excitation coil is disconnected, the moving iron core loses its magnetism and is acted by the return spring But separated from the static iron core, the normally open contact is reset and disconnected, and the external circuit is cut off accordingly.

The working process of this conventional AC contactor can be divided into three stages: "pulling", "holding" and "resetting":

1. Pull-in: The excitation coil is connected to the AC voltage, and the moving and static iron cores are pulled together. At this stage, in order to overcome the inertia of the moving iron core and the elastic force of the return spring, the excitation power supply must provide a large power (hereinafter referred to as the "pulling power"), so that the moving and static iron cores can attract each other.

2. Holding: The excitation coil continues to be connected to the AC voltage, and the moving and static iron cores continue to maintain the state of attraction. At this stage, the excitation power supply only needs to provide a small power (hereinafter referred to as "holding power"), and the moving and static iron cores can also continue to attract. If at this stage, the excitation power supply provides excessive holding power, it will cause waste of electric energy and lead to undue heating of the AC contactor;

3. Reset: The excitation coil is disconnected from the AC voltage, and the moving and static iron cores are "reset" separated.

AC contactors have different purposes and structures, but their working principles are the same as those shown in Figure 1.

In conventional AC contactors, the same AC voltage is passed through the excitation coil in both the pull-in and hold stages.

Therefore there are the following serious disadvantages:

1. Unnecessary power consumption: As mentioned above, in the pull-in and hold stages, the "same" AC voltage is passed through the excitation coil of the conventional AC contactor, which makes the hold power too large, resulting in unnecessary electric energy loss;

2. Heating: The evil result of unnecessary power loss is "heating and heating". In severe cases, it will even burn the excitation coil of the conventional AC contactor;

3. There is annoying humming noise.

Aiming at the serious shortcomings of conventional AC contactors, technicians in the electronics and electrical industry have researched and designed a variety of "power-saving circuits", "power savers" and "energy-saving AC contactors" to improve the performance of conventional AC contactors. - Hereinafter collectively referred to as "existing technology".

The above-mentioned prior art has indeed made useful explorations and achieved certain achievements in order to improve the performance of conventional AC contactors, but generally has the following defects: no "transient voltage (voltage transient)" suppression measures, no "suppression Transient voltage" function.

The load of the AC contactor, such as the motor, will generate a self-induction electromotive force (self induction electromotive force) with a high voltage value at the moment of starting or shutting down - hereinafter collectively referred to as "transient voltage". Because the "prior art" does not have "transient voltage" suppression measures, the "transient voltage" will enter the "energy-saving AC contactor" referred to in the "prior art" through the AC voltage input port, The capacitors, thyristors and other devices may be damaged due to breakdown!

This is one of the reasons why most of the "energy-saving AC contactors" referred to in the prior art remain on paper and are rarely used.

Aiming at the conventional AC contactor and the current state of the prior art, the goal of the present invention is: "Apply electronic technology to transform traditional industries", design a simple electronic circuit, use as few components as possible, and be as cheap as possible. It is a "single-pulse AC contactor capable of suppressing transient voltage" that surpasses the existing technology and can save electricity efficiently.

Contents of the invention

A single-pulse AC contactor capable of suppressing transient voltages, including a moving contact MC, a normally closed contact NC, a normally open contact NO, a moving iron core M, a static iron core G, a return spring F, and an excitation coil The conventional AC contactor and electronic unit 100 composed of L are characterized in that: the electronic unit 100 is composed of a transient voltage suppression diode TVS, an AC-DC conversion circuit 101, a single pulse generating circuit 102, and a switching circuit 103 , a bridge circuit 104, and a step-down circuit 105, wherein the transient voltage suppression diode TVS is connected in parallel with the AC-DC conversion circuit 101, one end is connected to the P1 end of the AC voltage, and the other end is connected to the AC The P2 terminal of the voltage is connected; the DC voltage output by the AC-DC conversion circuit 101 is Vcc; the 3-terminal of the single pulse generating circuit 102 is connected with the positive terminal of the Vcc voltage, and the 4-terminal is connected with the positive terminal of the switch circuit 103 5 ends are connected; the 6 ends of the switch circuit 103 are connected with the DC2 end of the bridge circuit 104; the AC1 end of the bridge circuit 104 is connected with the P1 end of the AC voltage, and the DC1 end is connected with the described The A1 end of the excitation coil L is connected, and the DC2 end is connected with the A2 end of the excitation coil L; the 7-end of the step-down circuit 105 is connected with the AC2 end of the bridge circuit 104; The negative end of the DC voltage Vcc output by the AC-DC conversion circuit 101 and one end of each of the single pulse generating circuit 102, the switch circuit 103, and the step-down circuit 105 are all connected to the P2 end of the AC voltage.

The electronic unit 100 is combined with the conventional AC contactor in the above-mentioned manner to form the "single-pulse AC contactor capable of suppressing transient voltage" in the present invention.

Described single pulse generation circuit 102 can adopt multiple circuit structures, and the present invention preferably following a kind of: it is made up of first resistor R1, second resistor R2, first capacitor C1, integrated time base circuit IC, 3 terminals, Composed of 4 terminals; wherein, 3 terminals are connected to the positive terminal of the DC voltage Vcc output by the AC-DC conversion circuit 101; one terminal of the first resistor R1 is connected to the 3 terminal, and the other terminal is connected to one terminal of the first capacitor C1 1. One end of the second resistor R2 is connected to pin 6 and pin 2 of the integrated time base circuit IC; pin 8 and pin 4 of the integrated time base circuit IC are connected to terminal 3, and pin 3 is connected to terminal 4; The other end of the first capacitor C1, the other end of the second resistor R2, and the pin 1 of the integrated time base circuit IC are all connected to the P2 end of the AC voltage.

The working characteristics of the single pulse generating circuit 102 are: in the working cycle of the AC contactor pull-in, hold and reset, it only outputs a single pulse, and, in the AC contactor pull-in phase , pin 3 of the integrated time base circuit IC outputs a high level, which is the "occupancy" time domain of the single pulse.

In the single pulse generating circuit 102, the integrated time base circuit IC is a 555 integrated time base circuit, and according to its operating characteristics, the 555 integrated time base circuit can be replaced by a triode or an integrated operational amplifier;

Described switch circuit 103 can adopt multiple circuit structure, and the present invention preferably following circuit structure: it is made up of the 3rd resistance R3, the 5th diode D5, Field Effect Transistor FET (Field Effect Transistor, FET), 5 terminals , 6 terminals; wherein, one end of the third resistor R3 is connected to the 5 terminal, and the other end is connected to the gate of the field effect transistor FET; the drain of the field effect transistor FET is connected to the fifth The cathode of the diode D5 is connected to the terminal P2 of the AC voltage; the anode of the fifth diode D5 is connected to the terminal 6 .

The field effect transistor FET can use other switching devices such as a unidirectional thyristor (Silicon Controlled Rectifier, SCR), a bidirectional thyristor (Triode AC Switch, TRIAC), an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor) , IGBT), electron injection enhanced gate transistor (Injection Enhanced Gate Tansistor, IEGT), static induction thyristor (Static Induction Thyristor, SITH) or switching triode instead.

Described electric bridge circuit 104 can adopt multiple circuit structure, and the present invention preferably following circuit structure: it is made up of first diode D1, second diode D2, the 3rd diode D3, the 4th diode Tube D4, AC1 terminal, AC2 terminal, DC1 terminal, DC2 terminal, wherein, the cathode of the first diode D1 and the anode of the second diode D2 are connected to the AC1 terminal; the anode of the third diode D3 1. The anodes of the first diode D1 are all connected to the DC2 terminal; the negative poles of the second diode D2 and the fourth diode D4 are all connected to the DC1 terminal; the negative poles of the third diode D3, the first diode D3 The anodes of the four diodes D4 are all connected to the AC2 terminal.

The step-down circuit 105 can also adopt various circuit structures, and the present invention preferably adopts the following circuit structure: it is composed of the second capacitor C2 and 7 terminals; and, one terminal of the second capacitor C2 is connected to the 7 terminals The other end is connected to the P2 end of the AC voltage.

Apply the present invention, can obtain following beneficial effect:

1. High efficiency and power saving:

In order to illustrate the high power-saving efficiency of the present invention, we have done the following tests:

(1) First measure the power consumption of conventional AC contactors: commercially available CJX2-3201 AC contactors: 4.7W;

(2), test again by the technical scheme of the present invention: the above-mentioned commercially available CJX2-3201 type AC contactor adds the electronic unit 100 of the present invention to form the meaning of the present invention " double-pulse AC contact that can suppress transient voltage The power consumption of the device: 0.3W;

The measured results show that compared with the commercially available CJX2-3201 AC contactor, the power saving efficiency of the present invention can reach 93.6%.

2. Quiet and noiseless:

The "single-pulse AC contactor capable of suppressing transient voltage" referred to in the present invention is quiet and has no audible noise during operation.

The commercially available CJX2-3201 AC contactor has obvious and audible AC noise during operation.

3. Low heat operation: the present invention has the function of high efficiency and power saving, saves electric energy, and must run with low heat.

4. Material saving: the number of turns of the excitation coil L can be reduced by applying the present invention. The actual measurement shows that the number of turns of the exciting coil L of the above-mentioned commercially available CJX2-3201 AC contactor is removed by 800 turns, and the "single-pulse AC contactor capable of suppressing transient voltage" referred to in the present invention can still maintain " High efficiency, power saving, quiet and noiseless, low heat operation" excellent performance. By utilizing the advantage of the present invention, the AC contactor can reduce the consumption of expensive enamelled copper wires.

5. It has the function of suppressing transient voltage, which can protect the present invention from the damage of transient voltage, thereby ensuring the long-term reliable operation of the present invention.

In short: the application of the present invention can innovatively manufacture AC contactors with "energy saving, consumption reduction, quiet noise and reliable operation".

Description of drawings

Figure 1 is a working principle diagram of a conventional AC contactor;

Fig. 2 is a schematic block diagram of the present invention;

Fig. 3 is the schematic circuit diagram of embodiment 1;

Figure 4a is an AC voltage waveform diagram;

FIG. 4 b is a pulse waveform diagram output by a single pulse generating circuit 102 .

Detailed ways

Below in conjunction with accompanying drawing, illustrate the embodiment of the present invention.

Fig. 2 is a schematic block diagram of the present invention, and Fig. 3 is a schematic circuit diagram of Embodiment 1. In FIG. 2 : L is the excitation coil in a conventional AC contactor, and A1 and A2 are its two connection ports; the dotted line box 100 represents the electronic unit 100 of the present invention.

Combined with Figure 1 and Figure 2; a single-pulse AC contactor capable of suppressing transient voltages, including a moving contact MC, a normally closed contact NC, a normally open contact NO, a moving iron core M, and a static iron core G , a return spring F, and an excitation coil L to form a conventional AC contactor and an electronic unit 100, characterized in that the electronic unit 100 is composed of a transient voltage suppression diode TVS, an AC-DC conversion circuit 101, a single Generating circuit 102, switch circuit 103, bridge circuit 104, and step-down circuit 105, wherein, the transient voltage suppression diode TVS is connected in parallel with the AC-DC conversion circuit 101, and one end is connected to the P1 end of the AC voltage The other end is connected to the P2 end of the AC voltage; the DC voltage output by the AC-DC conversion circuit 101 is Vcc; the 3 ends of the single pulse generating circuit 102 are connected to the positive end of the Vcc voltage, Terminal 4 is connected to terminal 5 of the switch circuit 103; terminal 6 of the switch circuit 103 is connected to terminal DC2 of the bridge circuit 104; terminal AC1 of the bridge circuit 104 is connected to terminal P1 of the AC voltage , DC1 end is connected with the A1 end of the excitation coil L, and the DC2 end is connected with the A2 end of the excitation coil L; the 7 ends of the step-down circuit 105 are connected with the bridge circuit 104 The AC2 terminal is connected; the negative terminal of the DC voltage Vcc output by the AC-DC conversion circuit 101 and one terminal of the single pulse generating circuit 102, the switch circuit 103, and the step-down circuit 105 are all connected to the P2 terminal of the AC voltage.

The electronic unit 100 is combined with the conventional AC contactor in the above-mentioned manner to form the "single-pulse AC contactor capable of suppressing transient voltage" in the present invention.

In conjunction with Fig. 3: in embodiment 1:

The first resistor R1, the second resistor R2, the first capacitor C1, the integrated time base circuit IC, the 3 terminals, and the 4 terminals constitute the single pulse generating circuit 102 of the first embodiment; wherein, the 3 terminals are connected to the AC-DC The positive terminal of the DC voltage Vcc output by the conversion circuit 101 is connected; one terminal of the first resistor R1 is connected to the terminal 3, and the other terminal is connected to one terminal of the first capacitor C1, one terminal of the second resistor R2, and 6 terminals of the integrated time base circuit IC. Both pins and 2 pins are connected; 8 pins and 4 pins of the integrated time base circuit IC are connected to 3 terminals, and 3 pins are connected to 4 terminals; the other end of the first capacitor C1 and the second resistor R2 The other end, pin 1 of the integrated time base circuit IC is connected with the P2 end of the AC voltage.

The integrated time base circuit IC is a 555 integrated time base circuit, and according to its working characteristics, the 555 integrated time base circuit can be replaced by a triode or an integrated operational amplifier.

The third resistor R3, the fifth diode D5, the field effect transistor FET, the 5-terminal, and the 6-terminal constitute the switch circuit 103 of the first embodiment; wherein, one terminal of the third resistor R3 is connected to the 5-terminal, and the other One end is connected to the gate of the field effect transistor FET; the drain of the field effect transistor FET is connected to the cathode of the fifth diode D5, and the source is connected to the P2 terminal of the AC voltage; The anode of five diodes D5 is connected with terminal 6.

It should be clear to those skilled in the art that the field effect transistor FET described above can use other switching devices such as unidirectional thyristors, bidirectional thyristors, insulated gate bipolar transistors, electron injection enhanced gate transistors, static induction thyristors or switches triode instead.

The first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the AC1 terminal, the AC2 terminal, the DC1 terminal, and the DC2 terminal form the bridge circuit 104 of the first embodiment ; Wherein, the cathode of the first diode D1 and the anode of the second diode D2 are connected to the AC1 terminal; the anode of the third diode D3 and the anode of the first diode D1 are connected to the DC2 terminal ; The cathode of the second diode D2 and the cathode of the fourth diode D4 are both connected to the DC1 terminal; the cathode of the third diode D3 and the anode of the fourth diode D4 are both connected to the AC2 terminal.

In the first embodiment, the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 are integrated rectifiers.

The second capacitor C2 and the terminal 7 constitute the step-down circuit 105 of the first embodiment; wherein, one terminal of the second capacitor C2 is connected to the terminal 7, and the other terminal is connected to the P2 terminal of the AC voltage.

Combined with Figure 3, Figure 4a, Figure 4b:

When t=t1, the AC voltage is turned on, and the AC-DC conversion circuit 101 outputs a DC voltage Vcc. At this time, the voltage at both ends of the first capacitor C1 is the voltage Vi=0<1/3Vcc<2/3Vcc on pin 2 and pin 6 of the integrated time base circuit IC, and the voltage V3 on pin 3 of the integrated time base circuit IC is High level, that is, V3≈Vcc.

In the time domain from t1 to t3, the DC voltage Vcc output by the AC-DC conversion circuit 101 charges the first capacitor C1 through the first resistor R1, and the voltage Vi on the first capacitor C1 continuously rises.

When t=t3, the voltage on the first capacitor C1 is the voltage Vi on pin 6 and pin 2 of the integrated time base circuit IC > 2/3Vcc > 1/3Vcc, and the voltage on pin 3 of the integrated time base circuit IC is V3 Become low level, that is, V3≈0.

In the time domain from t3 to t4, the voltage on the first capacitor C1, that is, the voltage Vi on pin 6 and pin 2 of the integrated time base circuit IC is still in the state of Vi>2/3Vcc>1/3Vcc, and 3 of the integrated time base circuit IC The voltage V3 on the pin is still at a low level, and is still in the state of V3≈0.

From the above analysis, it can be seen that the voltage V3 on pin 3 of the integrated time base circuit IC is: t1~t3 time domain, which is the time domain occupied by the pulse, which is high level; t3~t4 time domain, which is the pulse empty time domain , which is low. Its pulse waveform is represented by Fig. 4b.

According to the above analysis, in conjunction with Fig. 3, Fig. 4a, Fig. 4b, below, set forth the working process of the present embodiment 1:

1. Suction:

When t=t1, the AC voltage is turned on, and the V3 is at a high level, which triggers the conduction of the field effect transistor FET after being divided by the third resistor R3. The AC voltage provides "pull-in power" for Embodiment 1 through the field effect transistor FET.

In the positive half cycle of the AC voltage when P1 is positive and P2 is negative, the current i in the excitation coil L follows the direction of P1—AC1 terminal—D2—DC1 terminal—A1—excitation coil L—A2—DC2 terminal—6 terminal—D5—field The path of the effect tube FET-P2 flows through, and the excitation coil L charges and stores energy.

The moving iron core M is subjected to the action of the electromagnetic force generated by the exciting coil L, and starts to "pull in and start".

In the negative half cycle of the AC voltage when P1 is negative and P2 is positive, the fifth diode D5 is cut off. Since the current i in the excitation coil L cannot be mutated, it will continue to flow along the following two paths - called "freewheeling", or the discharge of the excitation coil L: the first path: A1—excitation coil L—A2—DC2 terminal—D1—AC1 terminal—D2—DC1 terminal—A1; the second path: A1—excitation coil L—A2—DC2 terminal—D3—AC2 terminal—D4—DC1 terminal—A1. The moving iron core M is affected by the electromagnetic force generated by the "freewheeling" current and continues to perform the action of "pulling in and starting".

When t=t2, the moving iron core M and the static iron core G are closed, and the "single-pulse AC contactor capable of suppressing transient voltage" completes the pull-in process and enters the hold phase.

2. Holding:

In the time domain from t2 to t3, V3 is still at high level, and the field effect transistor FET is still turned on; when t=t3, V3 becomes low level, and the field effect transistor FET is turned off. The current i in the time domain from t2 to t3 plays a role in consolidating the pull-in state of the "single-pulse AC contactor that can also suppress transient voltage".

In combination with Fig. 3, after the field effect transistor FET is turned off at t=t3, the AC voltage is stepped down by the second capacitor C2 to provide the "single-pulse AC contactor capable of suppressing transient voltage" holding power.

In the t3~t4 time domain:

When the AC voltage is the positive half cycle when P1 is positive and P2 is negative, the "holding current" i in the excitation coil L is along the direction of P1—AC1 terminal—D2—DC1 terminal—A1—excitation coil L—A2—DC2 terminal— D3—AC2 terminal—7 terminal—the second capacitor C2 (step-down)—the path flow of P2;

When the AC voltage is the negative half cycle when P1 is negative and P2 is positive, the "holding current" i in the excitation coil L goes along P2—second capacitor C2 (buck)—7 terminal—AC2 terminal—D4—DC1 terminal —A1—excitation coil L—A2—DC2 end—D1—AC1 end—P1 path circulation.

Only by adjusting the value of the second capacitor C2, the "holding current" or "holding power" can be adjusted to achieve the following two purposes:

(1) Make the "single-pulse AC contactor capable of suppressing transient voltage" reliable hold;

(2) Realize the above-mentioned first objective with the lowest possible "holding power".

3. Reset

When t=t4, the AC voltage is turned off, and the "holding current" i in the excitation coil L is along A1—excitation coil L—A2—DC2 terminal—D1—AC1 terminal—D2—DC1 terminal—A1 and A1—excitation coil L—A2—DC2 terminal—D3—AC2 terminal—D4—DC1 terminal—A1 two paths "freewheel" and gradually reduce to zero, and the "single pulse AC contactor that can also suppress transient voltage" is reset.

When t=t5, the AC voltage is turned on again, and the "single-pulse AC contactor capable of suppressing transient voltage" referred to in Embodiment 1 is energized again, and re-enters "pulling", "holding" and "resetting". in the working cycle.

In summary, we can see that:

1. The working characteristics of the single pulse generating circuit 102 are: in the working cycle of the AC contactor pulling, holding and resetting, it only outputs a single pulse, and the operation of the AC contactor The state is controlled by the "single pulse": in the pull-in phase of the AC contactor, the pin 3 of the integrated time base circuit IC outputs a high level, which is the "account" time of the single pulse domain; in the holding phase of the AC contactor, pin 3 of the integrated time base circuit IC outputs a low level, which is the "empty" time domain of the single pulse.

2. The bridge circuit 104 has two functions in the present invention, the first, the rectification function: the current in the excitation coil L is rectified into direct current; the second, the freewheeling function: the current in the excitation coil L Provides a "freewheeling" path.

Combined with FIG. 2 and FIG. 3 : one of the features of the present invention is: a transient voltage suppression diode TVS is provided at the input end of the AC voltage. The transient voltage suppression diode TVS plays the role of suppressing the external "transient voltage". If the transient voltage generated when being struck by lightning or the load of the AC contactor such as the transient voltage generated by the self-induced electromotive force when the motor starts and shuts off enters the electronic unit 100 of the present invention, the electronic unit 100 in the Devices such as integrated time base circuit IC, field effect tube FET may be damaged by breakdown. After the transient voltage suppression diode TVS is set at the input end of the AC voltage, when the voltage value of the "transient voltage" that enters from the outside is higher than the breakdown voltage of the transient voltage suppression diode TVS, it is equivalent to a short circuit , the electronic unit 100 of the present invention is protected.

The technical solution of the present invention has been described above, and all replacements that do not depart from the essence of the technical solution of the present invention should be within the scope of the claims of the present invention.

Claims (2)

1. a kind of and the pulse A.C. contactor of transient voltage can be restrained, including by movable contact, normally-closed contact, normally opened contact, Two part of regular alternating current contactor and electronic unit that dynamic iron core, static iron core, resetting spring, magnet exciting coil are formed, feature It is：By transient voltage suppressor, AC-DC conversion circuits, single pulse circuit, switch occur for the electronic unit Circuit, bridge circuit, reduction voltage circuit composition；Wherein, the transient voltage suppressor and the AC-DC conversion electricity Road is in parallel, one end is connected with the ends P1 of AC voltages, the other end is connected with the ends P2 of AC voltages；The AC-DC conversions The D/C voltage of circuit output is Vcc；3 ends that circuit occurs for the single pulse are connected with the anode of Vcc voltage, 4 ends with 5 ends of switching circuit are connected；6 ends of the switching circuit are connected with the ends DC2 of bridge circuit；The bridge circuit The ends AC1 be connected with the ends P1 of AC voltages, the ends DC1 are connected with the ends A1 of the magnet exciting coil, the ends DC2 are encouraged with described The ends A2 of magnetic coil are connected；7 ends of the reduction voltage circuit are connected with the ends AC2 of the bridge circuit；Described It is respective that circuit, switching circuit, reduction voltage circuit occur for the negative terminal and single pulse of the D/C voltage Vcc of AC-DC conversion circuits output One end is connected with the ends P2 of AC voltages；

Circuit occurs for the single pulse by first resistor, second resistance, the first capacitance, time-base integrated circuit, 3 ends, 4 end groups At；Wherein, the anode for the D/C voltage Vcc that 3 ends are exported with the AC-DC conversion circuits is connected；One end of first resistor with 3 ends are connected, and the other end is connected with one end of the first capacitance, one end of second resistance, 6 feet of time-base integrated circuit, 2 feet It connects；8 feet, 4 feet of time-base integrated circuit are connected with 3 ends, 3 feet are connected with 4 ends；The other end of first capacitance, The other end of second resistance, 1 foot of time-base integrated circuit are connected with the ends P2 of AC voltages；

The switching circuit is made of 3rd resistor, the 5th diode, field-effect tube, 5 ends, 6 ends；Wherein, the third Resistance one end is connected with 5 ends, and the other end is connected with the gate of the field-effect tube；Field-effect tube drain electrode with it is described The cathode of 5th diode is connected, source electrode is connected with the ends P2 of AC voltages；The anode of 5th diode is connected with 6 ends；

The bridge circuit by the first diode, the second diode, third diode, the 4th diode, the ends AC1, the ends AC2, The ends DC1, the ends DC2 composition, wherein the cathode of the first diode, the positive of the second diode are connected with the ends AC1；Three or two The anode of pole pipe, the positive of the first diode are connected with the ends DC2；The cathode of the cathode of second diode, the 4th diode It is connected with the ends DC1；The cathode of third diode, the positive of the 4th diode are connected with the ends AC2；

The reduction voltage circuit is made of the second capacitance, 7 ends；Also, the second described capacitance one end is connected with 7 ends It connects, the other end is connected with the ends P2 of AC voltages；

Wherein, the power consumption of pulse A.C. contactor that is described and can restraining transient voltage is 0.3W, and electric energy is 93.6%.

2. pulse A.C. contactor according to claim 1 and that transient voltage can be restrained, it is characterised in that：Described Time-base integrated circuit selects 555 time-base integrated circuits.