CN211908342U - Alternating-current multi-gear overcurrent protection circuit - Google Patents
Alternating-current multi-gear overcurrent protection circuit Download PDFInfo
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- CN211908342U CN211908342U CN202020208467.6U CN202020208467U CN211908342U CN 211908342 U CN211908342 U CN 211908342U CN 202020208467 U CN202020208467 U CN 202020208467U CN 211908342 U CN211908342 U CN 211908342U
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Abstract
The utility model discloses an AC multi-gear overcurrent protection circuit, which comprises a voltage stabilizing circuit, a sampling circuit and a relay circuit; the voltage stabilizing circuit is used for providing working voltage; the primary end of an alternating current transformer of the sampling circuit is coupled with a load, the secondary end of the alternating current transformer is coupled with two input ends of an operational amplifier respectively, the output end of the operational amplifier is coupled with a light emitter of an optical coupler, one end of a gear switch is coupled with the reverse input end of the operational amplifier, the other end of the gear switch is coupled with the output end of the operational amplifier, and the gear switch is used for adjusting the voltage of the output end of the operational amplifier; one end of a relay coil of the relay circuit is coupled with the voltage stabilizing circuit, the other end of the relay coil is coupled with the light receiver of the optical coupler and then grounded, the normally closed contact is coupled between the commercial power and the alternating current transformer, and the normally open contact is grounded. The utility model discloses in when the electric current exceeded the current protection value, the optical coupler switched on, and the relay coil got electric, and the common port of relay is connected rather than the normally closed end, and the load outage realizes overcurrent protection.
Description
Technical Field
The embodiment of the utility model provides a protection circuit is related to particularly, relates to an exchange many gears overcurrent protection circuit.
Background
The overcurrent protector is widely applied to various electrical appliances and electronic circuits, and mainly plays a role in overcurrent protection in circuits. The overcurrent protector commonly used in the market at present is mainly a overcurrent device with a fixed ampere, has the defect that the overcurrent protection value cannot be adjusted when an electrical appliance is changed, and in addition, more overcurrent protection circuits adopt a resistance sampling method, so that the circuits are easy to burn due to overlarge sampling resistance power when the current is large.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to the above-mentioned defect among the prior art, provide a can adjust many gears of interchange overcurrent protection circuit of current protection value.
In order to realize the purpose of the utility model, the utility model adopts the following technical scheme:
an alternating current multi-gear overcurrent protection circuit comprises a voltage stabilizing circuit, a sampling circuit and a relay circuit; the voltage stabilizing circuit is used for providing working voltage; the sampling circuit comprises an alternating current transformer, an operational amplifier, an optical coupler and a gear switch, wherein a primary end of the alternating current transformer is coupled with a load, a secondary end of the alternating current transformer is coupled with two input ends of the operational amplifier respectively, an output end of the operational amplifier is coupled with a light emitter of the optical coupler, one end of the gear switch is coupled with a reverse input end of the operational amplifier, the other end of the gear switch is coupled with an output end of the operational amplifier, and the gear switch is used for adjusting the voltage of the output end of the operational amplifier; the relay circuit comprises a coil, a normally closed contact and a normally open contact, one end of the coil is coupled with the voltage stabilizing circuit, the other end of the coil is coupled with the light receiver of the optical coupler and then grounded, the normally closed contact is coupled between the commercial power and the alternating current transformer, and the normally open contact is grounded.
Furthermore, the utility model discloses still provide following subsidiary technical scheme:
the gear switch comprises three resistance circuits which are connected in parallel, and each resistance circuit comprises a switch and a resistor which are connected in series.
The relay circuit further includes an over-current protection indication circuit coupled to the normally open contact of the relay circuit, which includes a first resistor and a first light emitting diode connected in series with each other.
The voltage stabilizing circuit comprises an alternating current step-down transformer, a bridge rectifier and a voltage stabilizing chip which are coupled in sequence, wherein the voltage stabilizing chip outputs a 12V voltage power supply.
The voltage stabilizing chip is LM7812, the input end of the voltage stabilizing chip is coupled with a filter capacitor C1, the output end of the voltage stabilizing chip is coupled with a filter capacitor C3 and a decoupling capacitor C5, and the filter capacitor C3 and the decoupling capacitor C5 are mutually connected in parallel.
The voltage stabilizing circuit further comprises a power supply indicating circuit, wherein the power supply indicating circuit is coupled between the bridge rectifier and the voltage stabilizing chip and comprises a resistor R5 and a second light emitting diode which are connected in series.
Compared with the prior art, the utility model has the advantages that: the utility model discloses a voltage stabilizing circuit, relay circuit and sampling circuit, gear switch through sampling circuit can adjust overcurrent current protection value, and when the electric current exceeded current protection value, the optical coupler among the sampling circuit switched on, and the relay coil was electrified, and the relay normally closed end communicates, and the load outage realizes overcurrent protection; the AC transformer is adopted to sample overcurrent, so that large current can be sampled, the circuit can be effectively prevented from being burnt, and the circuit safety is improved.
Drawings
In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments or related technologies will be briefly introduced below, and it is obvious that the drawings in the following description only relate to some embodiments of the present invention and are not limiting to the present invention.
Fig. 1 is a circuit diagram of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the present invention, taken in conjunction with the accompanying drawings and the detailed description, is given in a non-limiting manner.
As shown in fig. 1, the ac multi-tap overcurrent protection circuit includes a voltage stabilizing circuit, a sampling circuit and a relay circuit, the voltage stabilizing circuit is used for providing a working voltage, the sampling circuit is used for obtaining a load current value, and the relay circuit is used for controlling whether a load is powered.
The voltage stabilizing circuit is used for outputting 12V voltage and comprises an alternating current step-down transformer T2, a bridge rectifier Z2, a power supply indicating circuit, a filter capacitor C1, a voltage stabilizing chip U3, a filter capacitor C3 and a decoupling capacitor C5, wherein the power supply indicating circuit comprises a resistor R5 and a second light emitting diode LED 2. An ac step-down transformer T2 is coupled between the mains and the bridge rectifier Z2 for stepping down 220 vac to 15 vac. The bridge rectifier Z2 is also coupled to the input of the regulator chip U3, which rectifies the ac power to dc power and then feeds the dc power to the regulator U3. Resistor R5 and second LED2 are coupled in series between the input of the regulator and ground. The filter capacitor C1 is coupled between the input terminal of the voltage regulator chip U3 and the ground, and the filter capacitor C3 and the decoupling capacitor C5 are coupled between the output terminal of the voltage regulator U3 and the ground after being connected in parallel. In this embodiment, the resistance of the resistor R5 is 10K, the specification of the filter capacitor C1 is 1000UF/35V, the specification of the filter capacitor C3 is 100UF/25V, the model of the decoupling capacitor C5 is 104 capacitor, and the second LED2 is a green LED.
The sampling circuit comprises an alternating current transformer CT1, an operational amplifier U1A, an optical coupler U2 and a gear switch S1. The ac transformer CT1 has a primary terminal coupled to the load FZL1, a secondary terminal coupled to two input terminals of the operational amplifier U1A, and an output terminal of the operational amplifier U1A coupled to the optocoupler U2. The model of the operational amplifier U1A is OP07, and is used for converting current into voltage; the type of the optocoupler U2 is PC817, and the operational amplifier U1A of the type is a one-way optocoupler with the turn-on voltage of 1.2V. One end of the shift switch S1 is coupled with the inverting input end of the operational amplifier, the other end is coupled with the output end of the operational amplifier, the shift switch S1 comprises three paths of mutually parallel resistance circuits, each path of resistance circuit comprises a switch and a resistor which are mutually connected in series, wherein the resistance value of the first path of resistor R2 is 240 Ω, the resistance value of the second path of resistor R4 is 120 Ω, and the resistance value of the third path of resistor R3 is 80 Ω.
The relay circuit comprises a coil JD1, a normally closed contact, a normally open contact and an overcurrent protection indicating circuit, wherein the overcurrent protection indicating circuit comprises a first resistor R1 and a first light-emitting diode D1. One end of the coil JD1 is coupled to the voltage regulator chip U3, and the other end is coupled to the photo-detector of the photo-coupler U2 and then grounded. The normally closed contact is coupled between the commercial power and the alternating current transformer CT1, the normally open contact is coupled with one end of a first resistor R1, the other end of the first resistor R1 is coupled with the anode of a first light-emitting diode D1, and the cathode of the first light-emitting diode D1 is coupled with a bridge rectifier Z2 of the voltage stabilizing circuit. Coil JD1 has one end connected to 12V voltage and the other end connected to ground through optocoupler U2. In this embodiment, the first resistor R1 has a resistance of 36K, and the first led D1 is a red led.
The utility model discloses a theory of operation is:
when the gear switch S1 is turned on in the first path, when the total current in the load line exceeds 10A, the current at the secondary terminal of the ac transformer CT1 will exceed 5mA, and the current flowing through the resistor R2 will also exceed 5mA, so the voltage drop across the resistor R2 will exceed 5mA × 240 Ω to 1.2V, which causes the optocoupler U2 to be turned on, and then the coil JD1 is electrically operated, the common terminal is disconnected from the normally closed terminal and is connected to the normally open terminal, the load FZL1 is powered off, and the first light emitting diode D1 is turned on;
when the second path of the gear switch S1 is switched on, when the total current in the load line exceeds 20A, the current at the secondary terminal of the ac transformer CT1 will exceed 10mA, and the current flowing through the resistor R4 will also exceed 10mA, so the voltage drop across the resistor R4 will exceed 10mA by 120 Ω to 1.2V, which causes the optocoupler U2 to be turned on, and then the coil JD1 is electrically operated, the common terminal is disconnected from the normally closed terminal and is switched on with the normally open terminal, the load FZL1 is powered off, and the first light emitting diode D1 is turned on;
when the total current in the load line exceeds 30A when the gear switch S1 is turned on, the current at the secondary side of the ac transformer CT1 will exceed 15mA, and the current flowing through the resistor R3 will also exceed 15mA, so the voltage drop across the resistor R3 will exceed 15mA by 80 Ω to 1.2V, which will turn on the optocoupler U2, and then the coil JD1 is electrically operated, the common terminal is disconnected from the normally closed terminal and is connected with the normally open terminal, the load FZL1 is powered off, and the first light emitting diode D1 is turned on.
Claims (6)
1. An alternating current multi-gear overcurrent protection circuit is characterized by comprising a voltage stabilizing circuit, a sampling circuit and a relay circuit;
the voltage stabilizing circuit is used for providing working voltage;
the sampling circuit comprises an alternating current transformer, an operational amplifier, an optical coupler and a gear switch, wherein a primary end of the alternating current transformer is coupled with a load, a secondary end of the alternating current transformer is coupled with two input ends of the operational amplifier respectively, an output end of the operational amplifier is coupled with a light emitter of the optical coupler, one end of the gear switch is coupled with a reverse input end of the operational amplifier, the other end of the gear switch is coupled with an output end of the operational amplifier, and the gear switch is used for adjusting the voltage of the output end of the operational amplifier;
the relay circuit comprises a coil, a normally closed contact and a normally open contact, one end of the coil is coupled with the voltage stabilizing circuit, the other end of the coil is coupled with the light receiver of the optical coupler and then grounded, the normally closed contact is coupled between the commercial power and the alternating current transformer, and the normally open contact is grounded.
2. An alternating current multi-tap overcurrent protection circuit according to claim 1, wherein: the gear switch comprises three resistance circuits which are connected in parallel, and each resistance circuit comprises a switch and a resistor which are connected in series.
3. An alternating current multi-tap overcurrent protection circuit according to claim 1, wherein: the relay circuit further comprises an overcurrent protection indicating circuit, the overcurrent protection indicating circuit is coupled with the normally open contact of the relay circuit and comprises a first resistor and a first light emitting diode which are connected in series.
4. An alternating current multi-tap overcurrent protection circuit according to claim 1, wherein: the voltage stabilizing circuit comprises an alternating current step-down transformer, a bridge rectifier and a voltage stabilizing chip which are coupled in sequence, wherein the voltage stabilizing chip outputs a 12V voltage power supply.
5. An alternating current multi-tap overcurrent protection circuit according to claim 4, wherein: the voltage stabilizing chip is LM7812, the input end of the voltage stabilizing chip is coupled with a filter capacitor C1, the output end of the voltage stabilizing chip is coupled with a filter capacitor C3 and a decoupling capacitor C5, and the filter capacitor C3 and the decoupling capacitor C5 are connected in parallel.
6. An alternating current multi-tap overcurrent protection circuit according to claim 4, wherein: the voltage stabilizing circuit further comprises a power supply indicating circuit, wherein the power supply indicating circuit is coupled between the bridge rectifier and the voltage stabilizing chip and comprises a resistor R5 and a second light emitting diode which are connected in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020208467.6U CN211908342U (en) | 2020-02-25 | 2020-02-25 | Alternating-current multi-gear overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020208467.6U CN211908342U (en) | 2020-02-25 | 2020-02-25 | Alternating-current multi-gear overcurrent protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN211908342U true CN211908342U (en) | 2020-11-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020208467.6U Expired - Fee Related CN211908342U (en) | 2020-02-25 | 2020-02-25 | Alternating-current multi-gear overcurrent protection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114243633A (en) * | 2021-12-22 | 2022-03-25 | 国网江苏省电力有限公司宿迁供电分公司 | 10kV metering TV high-voltage overcurrent self-recovery protection hardware circuit and device |
-
2020
- 2020-02-25 CN CN202020208467.6U patent/CN211908342U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114243633A (en) * | 2021-12-22 | 2022-03-25 | 国网江苏省电力有限公司宿迁供电分公司 | 10kV metering TV high-voltage overcurrent self-recovery protection hardware circuit and device |
| CN114243633B (en) * | 2021-12-22 | 2023-07-04 | 国网江苏省电力有限公司宿迁供电分公司 | High-voltage overcurrent self-recovery protection hardware circuit and device for 10kV metering TV |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20201110 Termination date: 20210225 |
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| CF01 | Termination of patent right due to non-payment of annual fee |