CN2293146Y - Contactor power supply overvoltage protection circuit - Google Patents
Contactor power supply overvoltage protection circuit Download PDFInfo
- Publication number
- CN2293146Y CN2293146Y CN 97211731 CN97211731U CN2293146Y CN 2293146 Y CN2293146 Y CN 2293146Y CN 97211731 CN97211731 CN 97211731 CN 97211731 U CN97211731 U CN 97211731U CN 2293146 Y CN2293146 Y CN 2293146Y
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- CN
- China
- Prior art keywords
- resistance
- contactor
- piezo
- power supply
- control circuit
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model discloses a contactor power supply overvoltage protection circuit which is connected between a control power supply of a contactor and a control circuit. When a power supply overvoltage impulse is generated, voltages at both ends of a varistor is effectively limited by a current-limiting resistor, a rectifier diode in a contactor control circuit is prevented from being broken down and damaged, and the contactor whose control circuit is provided with rectifier elements can be safely operated in a situation that various inductances and capacitive loads are frequently operated and switched.
Description
The utility model belongs to power operation over-voltage protection technique field, specifically a kind of power operation excess voltage protection of contactor control circuit.
The vacuum contactor of domestic production at present is as the CKJ of unit consolidations such as Shanghai Electric Appliances Science Inst design
5-250A AC vacuum contactor is the product of representative, its action adhesive device adopts the direct current magnetic system, when this contactor is used for ac control power supply work, adopt full-wave bridge rectifier circuit that exchange conversion is become direct current in the control circuit, supply the DC electromagnet adhesive and keep usefulness.Rectification circuit generally all directly is attempted by on the power frequency supply, as 220V or 380V etc. when connecting.The diode that rectification is used has the parameter of high reverse breakdown voltage, and diode is with punch through damage when the reverse breakdown voltage of transdiode.Just often because the reverse breakdown voltage of rectifier diode greater than the crest voltage of control power supply, is gone back deficiency so that diode breakdown.When the contactor major loop is applied in the rotating switching of perception and the switching of capacitive load, motor, will produce the pulse operation overvoltage of several times even nearly ten times in the power supply, moment just punctures the rectifier diode in the control circuit.For the present manufacturer of head it off generally at the input (just controlling both ends of power) of control circuit and connect piezo-resistance; in order to the suppressor pulse switching overvoltage; the protection rectifier diode; though played certain effect; but also do not deal with problems fully; its reason is: the piezo-resistance of input is directly to be attempted by on the power supply; the internal resistance of power supply is very for a short time to be similar to zero; when the very big pulse operation overvoltage of produce power in the power supply; this voltage will directly be added on the piezo-resistance; make the electric current that flows through piezo-resistance surpass its peak inrush current; light then make the lost of life of piezo-resistance; heavy then make cloudy explosion of pressure-sensitive electricity or puncture; and rectifier diode is also too high often breakdown because of the voltage at piezo-resistance two ends, and this is because the voltage that the piezo-resistance two ends can be limited is and flows through the current related of piezo-resistance.The nominal voltage value of piezo-resistance is meant the magnitude of voltage the when electric current that flows through piezo-resistance is 1mA, when the pulse current that flows through piezo-resistance is tens of peaces, hundreds of peace even thousands of ampere-hour, the deboost at piezo-resistance two ends will be the several times of nominal voltage, the big more voltage that can limit of electric current is just high more, and the possibility of the anti-phase punch through damage of rectifier diode is just big more.Because the rectifier diode reverse breakdown voltage of using in the contactor control circuit has been used the higher level of common tube, piezo-resistance is also owing to reasons such as volume, cost can not be with the bigger grade of through-current capacity, so present vacuum contactor in, still have certain difficulty in the application of the frequent operation occasion of powerful perception and capacitive load, especially 380V and 220V control electric pressure, and many users use the back have to be forced to change because of the control circuit poor reliability.
The purpose of the present utility model is: solve the rectifier cell in the present vacuum contactor control circuit; because of the power operation overvoltage often punch through damage cause the problem that contactor can not reliability service; provide a kind of and can effectively suppress the superpotential protective circuit of power operation, guarantee that the rectifier diode in the contactor control circuit can trouble free service.
For solving above-mentioned task; solution of the present utility model is: between the input of control power supply and contactor control circuit; connect shirtsleeve operation excess voltage protection of forming by resistance and piezo-resistance; especially the current-limiting resistance that is connected in series between the power supply of piezo-resistance and control; the pulse current of piezo-resistance when being used for limiting switching overvoltage, thus the deboost at assurance piezo-resistance two ends is in allowed limits.
The present utility model is to utilize the pressure limiting of the metering function of resistance and piezo-resistance to be used for playing to the superpotential inhibition of power operation, and wherein series resistance mainly is when having the pulse operation overvoltage to produce piezo-resistance to be played metering function and dividing potential drop effect.Because the existence of series resistance is arranged, just can not produce very big even infinitely-great pulse current in the piezo-resistance, pulse current in the big more piezo-resistance of resistance is just more little, otherwise then big, so this resistance can play the effect of the pulse current in effective restriction piezo-resistance.Resistance and piezo-resistance are to be attempted by after the series connection on the control power supply in addition, when overvoltage pulse produces, piezo-resistance will reduce internal resistance moment and produce through-flow effect, it and current-limiting resistance are formed bleeder circuit together, except that certain deboost that piezo-resistance produced, the voltage of overage will all fall on current-limiting resistance.Suitably the electric current in the big I assurance piezo-resistance of selection current-limiting resistance is less than the peak inrush current of its permission, the voltage at piezo-resistance two ends is less than its maximum constraints voltage, also less than the reverse breakdown voltage of rectifier diode, thereby guarantee that the rectifier diode in the contactor control circuit can punch through damage.Again because the pulse through-current capacity of piezo-resistance is very big, also reaching more than the 1KA of 10K type so in fact current-limiting resistance very little, general several ohm resistance just can play good metering function to piezo-resistance, and so little resistance is to the starting adhesive of contactor control circuit with keep almost and have no impact.
The switching overvoltage protective circuit that has adopted the simplest resistance and piezo-resistance to form in the above-mentioned solution; can effectively suppress too high pulse operation overvoltage and enter the contactor control circuit; thereby protected the rectifier diode in the control circuit; make the AC vacuum contactor of direct current magnetic system, can be applied in the occasion of the frequent operation of various perception and capacitive load reliably.
Fig. 1 is the electrical schematic diagram of contactor power operation excess voltage protection of the present utility model.
Fig. 2,3 is the electrical schematic diagram of several embodiment of the present utility model.
Among Fig. 1: (1), (5) are the control power input, and (3), (5) are the protective circuit output, and current-limiting resistance (2) is serially connected with between input (1) and the output (3), and piezo-resistance (4) is attempted by between output (3), (5).When having the switching overvoltage pulse to produce between the input (1) of controlling power supply, (5), piezo-resistance (4) moment produces through-flow effect, the effect of the limited size leakage resistance (2) of its electric current and being controlled in certain scope, the piezo-resistance two ends produce a deboost immediately, the pulse surge that surpasses the deboost part will all fall on current-limiting resistance (2), thereby the overvoltage Limiting between assurance output (3), (5) in allowed limits, guarantees the contactor control circuit safe operation of back.
Fig. 2 is the vacuum contactor control circuit electrical schematic diagram that the switching overvoltage protection is arranged of double winding, two-wire bag pattern.Among the figure: V
1-V
4Be rectifier diode, Y
1A, Y
2A is the electromagnet actuating coil, Y
1B, Y
2BFor keeping coil, S is used to the auxiliary switch that starts and keep.
Fig. 3 is the vacuum contactor control circuit electrical schematic diagram that the switching overvoltage protection is arranged of single line bag pattern.Among the figure: V
1-V
4Be rectifier diode, Y is an electromagnet coil, and C is for keeping element, and S is used to the auxiliary switch that starts and keep.
Though the contactor control circuit in Fig. 2, the 3 two kinds of embodiments is different, the circuit that they are used for the switching overvoltage protection is identical, so same Fig. 1 of principle of switching overvoltage protection.(1), (5) two termination contactors control power supply during operate as normal, the nominal voltage of piezo-resistance is greater than the crest voltage of control power supply, this moment, piezo-resistance was in open-circuit condition, current-limiting resistance (2) in fact is serially connected in the input circuit of contactor control circuit, because the resistance of current-limiting resistance is very little, the pressure drop that it produced is to the starting adhesive of contactor control circuit and keep almost and have no impact.
The application of protective circuit also is not limited to the form of above-mentioned several control circuits, can also be other form.For the contactor finished product that does not have the switching overvoltage protection, then only need the device of an additional switching overvoltage protective circuit to get final product.Use AC power when protective circuit also can be applicable to the starting of alternating magnetic system structure, be converted to after the adhesive on the vacuum of keeping with the direct voltage behind the diode rectification or air contactor.
Optimum implementation of the present utility model is: the resistance of current-limiting resistance (2) can generally be chosen in 0.5 Ω～20 Ω scopes according to the contactor control circuit of different electric currents, electric pressure.
Claims (2)
1, a kind of contactor power operation excess voltage protection; mainly formed by piezo-resistance (4); its input (1), (5) are connected with contactor control power supply; output (3), (5) are connected with the input of contactor control circuit; it is characterized in that a current-limiting resistance (2) in addition; its end is connected with the input (1) of control power supply, and the other end is connected with output (3) with piezo-resistance (4).
2, a kind of contactor power operation excess voltage protection according to claim 1 is characterized in that the resistance of current-limiting resistance (2) is generally chosen in 0.5 Ω～20 Ω scopes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97211731 CN2293146Y (en) | 1997-03-04 | 1997-03-04 | Contactor power supply overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97211731 CN2293146Y (en) | 1997-03-04 | 1997-03-04 | Contactor power supply overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2293146Y true CN2293146Y (en) | 1998-09-30 |
Family
ID=33930146
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 97211731 Expired - Fee Related CN2293146Y (en) | 1997-03-04 | 1997-03-04 | Contactor power supply overvoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2293146Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022151653A1 (en) * | 2021-01-14 | 2022-07-21 | 南方电网数字电网研究院有限公司 | Switching circuit, power supply device, and electrical device |
-
1997
- 1997-03-04 CN CN 97211731 patent/CN2293146Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022151653A1 (en) * | 2021-01-14 | 2022-07-21 | 南方电网数字电网研究院有限公司 | Switching circuit, power supply device, and electrical device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |