TW201941511A - Relay protection device - Google Patents

Abstract

The semiconductor device comprises a first semiconductor, a second semiconductor, a first resistor, a photocoupler and a relay, constituting an application circuit having a load overload or short-circuit protection function, which avoids the damage caused by overload or short-circuit at both terminals of the load.

Description

Relay protection

The relay protection device of the present invention has the protection function of overload or short circuit occurring at both ends of a load during a circuit application process, and an electronic technology field including a first semiconductor, a second semiconductor, a first resistor, a photocoupler, and a relay.

As shown in FIG. 1, it is a circuit diagram of a conventional battery protection device. When the switch 83 is closed, the current of the DC power source 81 passes the positive terminal of the DC power source 81 through the fuse 82 or the thermal circuit breaker, and then supplies power to the relay circuit through the switch 83 The first end C1 of the electromagnetic coil 85 and the second end C2 of the electromagnetic coil return to the negative electrical end of the DC power supply 81 to complete the power supply action of the relay 85. At this time, the first contact K1 and the second contact K2 of the relay 85 The conductive DC power source 81 supplies power to the load 84. When a short circuit occurs across the load 84, the fuse 82 is blown or the thermal circuit breaker is tripped to protect the battery 81 from damage. It has the following disadvantages:

1. When the DC power supply and the fuse are connected in series to the load, if a short circuit occurs at the load end, the fuse will blow when the short-circuit current reaches the melting point of the fuse, and the DC power supply will open circuit with the load. In addition, sparks are generated when the fuse is blown, which may cause a fire hazard and replace the fuse. It takes a waste of time.

2. When the DC power supply is connected to the thermal circuit breaker in series to supply power to the load, if a short circuit occurs at the load end, when the short-circuit current reaches the thermal circuit breaker's heat, the contact point of the thermal circuit breaker trips, and the DC power supply opens to the load end. The disadvantages are the current loss of the thermal circuit breaker before it trips, and the cooling time or manual pressure recovery action of the thermal circuit breaker to restore the original state, and the temperature at which the contact point trips is different from the recovery temperature. The Thermal Circuit Breaker has a life limit for the number of operations.

Purpose of the invention:

The invention applies the first semiconductor, the second semiconductor, the first resistor, the photocoupler and the relay, and can protect the DC power supply when the load is overloaded or short-circuited during the DC power supply.

The present invention uses a first semiconductor, a second semiconductor, a first resistor, a photocoupler, and a relay, plus a full-wave rectifier, to protect the AC power source when the load is overloaded or short-circuited during the AC power supply.

When the load is short-circuited, the invention uses the first semiconductor and the relay to perform the open circuit action of the second semiconductor in a very short time, to achieve the function of protecting the DC power supply or the AC power supply and avoiding various disasters caused by the load short-circuit.

The present invention uses a photocoupler to perform the reset function of the present invention. When the cause of the short circuit is eliminated, it is not necessary to resend the DC power or AC power.

The invention has the following features:

1. The relay of the present invention is provided with an electromagnetic coil and two contacts, which are responsible for supplying power to the load by turning off and on the DC power source or the AC power source.

2. The first semiconductor of the present invention, which is responsible for controlling the electromagnetic of the relay The coil opens and conducts.

3. The second semiconductor of the present invention is responsible for controlling the opening and conducting actions of the first semiconductor circuit.

4. The photocoupler of the present invention is responsible for the reset function. When the load is short-circuited, it is not necessary to restart the open circuit and conduction of the DC power supply or AC power supply.

5. The first semiconductor of the present invention is an N-channel metal oxide semiconductor field effect transistor.

6. The second semiconductor of the present invention includes an N-type transistor or an N-channel metal oxide semiconductor field effect transistor. Both can be selected according to demand.

7. The photocoupler used in the present invention has a transistor output type and a thyristor output type, which can be selected according to demand.

8. The time control circuit of the present invention selects a resistance-capacitance time constant circuit or other time control circuits.

11‧‧‧First Semiconductor

12‧‧‧Second Semiconductor

13‧‧‧Photocoupler transistor output type

14‧‧‧ Relay

15‧‧‧Third Semiconductor

16‧‧‧Photocoupler brake fluid output type

17‧‧‧full wave rectifier

21‧‧‧first resistor

22‧‧‧Second resistor

23‧‧‧first capacitor

30‧‧‧ the first end

40‧‧‧ second end

50‧‧‧ third end

60‧‧‧First switch

R‧‧‧ the main contact of the first switch

V‧‧‧ the first contact of the first switch

U‧‧‧ the second contact of the first switch

T‧‧‧ the third contact of the first switch

100‧‧‧ Relay protection device of the present invention

200‧‧‧ load

300‧‧‧DC Power

310‧‧‧First DC Power Supply

320‧‧‧second DC power supply

400‧‧‧AC power

500‧‧‧AC load

FIG. 1 is a circuit diagram of a conventional battery protection device.

FIG. 2 is a circuit diagram of a relay protection device according to the present invention.

FIG. 3 is a first embodiment of a relay protection device according to the present invention.

FIG. 4 is a second embodiment of the relay protection device of the present invention.

FIG. 5 is a third embodiment of the relay protection device of the present invention.

As shown in FIG. 2, it is a circuit diagram of the relay protection device of the present invention. As can be seen from the figure, the relay protection device 100 of the present invention includes a first semiconductor 11 (First Semiconductor, 11), a second semiconductor 12 (Second Semiconductor, 12), First resistor 21 (First Resistor, 21), Photocoupler 13 (Photocoupler, 13) and Relay 14 (Relay, 14); the first end is connected to First Switch 60 (First Switch, 60), Time Control Circuit 70 (Time Controll Circuit, 70), load 200 (Load, 200), DC power source 300 (DC Power Source, 300); the source S (Source, S) of the first semiconductor 11 is connected to the emitter E (Emitter, E) of the second semiconductor 12, The cathode terminal N (Cathode, N) of the photocoupler 13, the second contact K2 and the third terminal 50 of the relay 14; the gate G (Gate, G) of the first semiconductor 11 is connected to the collector C of the second semiconductor 12 (Collector, C) and the other end of the first resistor 21, one end of the first resistor 21 is connected to the first end C1 and the first end 30 of the electromagnetic coil of the relay 14, and the second end C2 of the electromagnetic coil of the relay 14 is connected to the first The drain D (Drain, D) of the semiconductor 11; the base G (Base, B) of the second semiconductor 12 is connected to the emitter E of the photocoupler 13, and the collector C of the photocoupler 13 is connected to the first connection of the relay 14. Point K2 and the second terminal 40; the anode terminal P (Anode, P) of the photocoupler 13 is connected to the output terminal 72 of the time controller 70; the first terminal 30 is connected to the main contact R of the first switch 60 and the time control circuit 70 Lose At the input 71, the first switch 60 is provided with a main contact R, a first contact V, a second contact U, and a third contact T. The first contact V is connected to the positive electrical terminal of the DC power source 300 and the load 200. At one end, the other end of the load 200 is connected to the second end 40, the negative electrical end of the DC power supply 300 and the ground end 73 of the time control circuit 70 are connected to the third end 50; the first semiconductor 11 is an N-channel metal oxide semiconductor field effect transistor. The two semiconductors 12 are N-type transistors; the photocoupler 13 is a transistor output type. The input side is a light emitting diode (LED) and the output side is a transistor. The relay 14 is provided with an electromagnetic coil (Electric Magnetic Coil) First end C1, second end C2 of the electromagnetic coil, first contact K1 and second contact K2, the first The contact K1 and the second contact K2 constitute a group of contacts to perform the Open and On actions of the circuit.

As shown in FIG. 2, when the main contact R of the first switch 60 is turned to the first contact V, the positive terminal of the DC power source 300 is supplied to the first terminal 30 and the input terminal 71 of the time control circuit 70 at the same time. The power supply 300 supplies power from one end of the load 200 to the other end of the load 200 to the second end 40, and the negative electrical end of the DC power supply 300 is connected to the third end 50. At this time, the first end 30 supplies power to the first end of the electromagnetic coil of the relay 14. C1 and one end of the first resistor 21 pass through the other end of the first resistor 21 to the gate G of the first semiconductor 11 and the collector C of the second semiconductor 12, so the drain D and the source of the first semiconductor 11 S is turned on, and the solenoid coil of the relay 14 is supplied with voltage. The first contact K1 and the second contact K2 are conducted. The DC power source 300 supplies power to the load 200, and then the output terminal 72 of the time control circuit 70 supplies power to the photocoupler 13. The anode terminal P to the cathode terminal N. At this time, the collector C and the emitter E of the photocoupler 13 are turned on. Because the first contact K1 and the second contact K2 of the relay 14 are turned on, the base B of the second semiconductor 12 is turned on. Since the voltage with the emitter E is low, the collector C and the emitter E of the second semiconductor 12 are open.

As shown in FIG. 2, when the main contact R of the first switch 60 is turned to the second contact U, the DC power source 300 does not supply power to the first terminal 30. At this time, the drain D and the source S of the first semiconductor 11 are at this time. Open circuit, the solenoid coil of relay 14 has no voltage supply, its first contact K1 and second contact K2 are open, DC power supply 300 is not supplying power to load 100, and at the same time, collector C and emitter E of photocoupler 13 are open circuit. The base B and the emitter E of the two semiconductors 12 have no voltage.

As shown in FIG. 2, when a DC power source 300 is connected to the first terminal 30, the DC power source 300 supplies power to both ends of the load 200. If the two ends of the load 200 are short-circuited, it is equivalent to powering the positive voltage of the DC power source 300 to The collector C of the photocoupler 13 is at this time because the collector C and the emitter E of the second semiconductor 12 are turned on, and the gate G and the source S of the first semiconductor 11 are turned on, so the drain of the first semiconductor 11 is turned on. D is open to the source S, and the solenoid coil of the relay 14 has no voltage supply. The first contact K1 and the second contact K2 are open. The DC power source 300 does not supply power to the load 200, and the short-circuit protection of the first DC power source 300 is achieved. purpose.

As shown in FIG. 2, when a DC power source 300 is connected to the first end 30, the DC power source 300 supplies power to both ends of the load 200. When a short circuit occurs in the load 200, the cause of the short circuit at both ends of the load 200 is removed, and then the first The main contact R of the switch 60 is turned to the second contact U and then to the first contact V. At this time, the collector C of the photocoupler 13 is connected to the emitter E, and the base B and the emitter E of the second semiconductor 12 are turned on. The voltage across the two terminals is low, the collector C and the emitter E of the second semiconductor 12 are open, and the gate G of the first semiconductor 11 receives a positive voltage. Therefore, the drain D and the source S of the first semiconductor 11 are turned on. The electromagnetic coil has a voltage supply, and the first contact K1 and the second contact K2 are turned on, and the DC power source 300 supplies power to the load 200. If the main contact R of the first switch 60 is turned to the second contact U, the DC power source 300 does not Power is supplied to the first terminal 30. At this time, the DC power supply 300 is not powered to the load 200.

As shown in FIG. 2, when a DC power source 300 is connected to the first terminal 30, the DC power source 300 supplies power to both ends of the load 200. If the load 200 is increased, the load 200 current is increased. When the voltage drop between the two points of a contact K1 and the second contact K2 is greater than the base-emitter on-voltage of the second semiconductor 12, the collector C and the emitter E of the second semiconductor 12 are turned on, and the gate of the first semiconductor 11 is turned on. Both ends of the electrode G and the source S are conducted, so that the drain D of the first semiconductor 11 and the source S are open, and the electromagnetic coil of the relay 14 has no voltage. Supply, its first contact K1 and second contact K2 are open, and the DC power source 300 does not supply power to the load 200, but achieves the purpose of overcurrent protection of the DC power source 300.

As shown in FIG. 3, this is the first embodiment of the relay protection device of the present invention. As can be seen from the figure, the time control circuit 70 selects a resistance-capacitance time constant circuit. The resistance in the resistance-capacitance time constant circuit is the second resistor 22. The capacitance in the resistance-capacitance time constant circuit is the first capacitor 23, one end of the second resistor 22 is connected to the first terminal 30 in the relay protection device 100 of the present invention, and the other end of the second resistor 22 is connected to the positive terminal of the first capacitor 23. The electrical terminal and the anode terminal P of the photocoupler 13, the negative electrical terminal of the first capacitor 23 is connected to the third terminal 50; the positive electrical terminal of the first DC power source 310 (First DC Power Source, 310) is connected to the first terminal of the first switch 60 A contact V and one end of the load 200, the other end of the load 200 is connected to the second end 40, the negative electrical end of the first DC power source 310 is connected to the third end 50, and the second DC power source 320 (Second DC Power Source, 320) The positive electrical terminal is connected to the third contact T of the first switch 60, and the negative electrical terminal of the second DC power source 320 is connected to the third terminal 50.

As shown in FIG. 3, the positive electric terminal of the first DC power source 310 is supplied to the main contact R of the first switch 60 and one end of the load 200, and then the other end of the load 200 is connected to the second end 40. The main contact R of the switch 60 is turned to the first contact V. The positive electrical terminal of the first DC power source 310 is supplied to one of the first terminal 30 and the second resistor 22. The positive voltage is provided to the first resistor 21 to the first. The gate G of the semiconductor 11 and the collector C of the second semiconductor 12 are connected. Therefore, the drain D of the first semiconductor 11 is connected to the source S, and the electromagnetic coil of the relay 14 is supplied with voltage. The first contact K1 is connected to the second contact. The point K2 is turned on, the first DC power source 300 supplies power to the load 200, and then the other end of the second resistor 22 supplies power to the anode terminal P of the photocoupler 13 to the cathode. Extreme N. At this time, the collector C and the emitter E of the photocoupler 13 are turned on, and the voltage between the base B and the emitter E of the second semiconductor 12 is low. Therefore, the collector C and the emitter E of the second semiconductor 12 are open. The second resistor 22 and the first capacitor 23 constitute a time constant circuit, which can control the conduction time between the anode terminal P and the cathode terminal N of the photocoupler 13 to achieve the control of the reset time. The circuit can be replaced by an equivalent function time controller without limitation.

As shown in FIG. 3, when the main contact R of the first switch 60 is turned to the second contact U, the first DC power source 310 does not supply power to the first terminal 30. At this time, the drain D of the first semiconductor 11 and the The source S is open, and the solenoid coil of the relay 14 has no voltage supply. The first contact K1 and the second contact K2 are open. The first DC power source 310 does not supply power to the load 200. The collector C of the photocoupler 13 and The electrode E is open, and the base B and the emitter E of the second semiconductor 12 have no voltage.

As shown in FIG. 3, when the main contact R of the first switch 60 is turned to the third contact T, the positive terminal of the second DC power source 320 is supplied to the first terminal 30 and the positive terminal of the first DC power source 310. The terminal is powered from the load 200 to the second terminal 40, and the negative terminal of the first DC power source 310 and the negative terminal of the second DC power source 320 are connected to the third terminal 50 because the second DC power source 320 is powered by the first terminal 30. At this time, the first terminal 30 supplies power to the gate G of the first resistor 21 to the first semiconductor 11 and the collector C of the second semiconductor 12. At this time, the drain D of the first semiconductor 11 and the source S are turned on, and the relay 14 The electromagnetic coil has a voltage supply. The first contact K1 and the second contact K2 are turned on. The first DC power source 310 supplies power to the load 200, and then supplies the anode terminal P and the photocoupler 13 via the second resistor 22. The cathode terminal N, at this time, the collector C and the emitter E of the photocoupler 13 are turned on, and the voltage between the base B and the emitter E of the second semiconductor 12 is low, so the second half The collector C and the emitter E of the conductor 12 are open.

As shown in FIG. 3, when the first terminal 30 is connected to the second DC power source 320, the first DC power source 310 supplies power to both ends of the load 200. If the two ends of the load 200 are short-circuited, it is equivalent to the first DC power source 310. The positive voltage is supplied to the collector C of the photocoupler 13. At this time, the collector C and the emitter E of the second semiconductor 12 are turned on, which is the same as that the gate G and the source S of the first semiconductor 11 are turned on, so the first The drain D and the source S of the semiconductor 11 are open-circuited, and the electromagnetic coil of the relay 14 has no voltage supply. The first contact K1 and the second contact K2 are open. The first DC power source 310 is not supplied to the load 200, and a short circuit is reached. Purpose of protecting the first DC power source 310.

As shown in FIG. 3, when the first terminal 30 is connected to the second DC power supply 320, the first DC power supply 310 supplies power to both ends of the load 200. When the load 200 is short-circuited, the cause of the short-circuit at both ends of the load 200 is removed first. Then, the main contact R of the first switch 60 is turned to the second contact U, and then to the third contact T. At this time, the collector C of the photocoupler 13 is connected to the emitter E, and the base of the second semiconductor 12 is turned on. The voltage across B and the emitter E is low, the collector C of the second semiconductor 12 is open with the emitter E, and the gate G of the first semiconductor 11 receives a positive voltage, so the drain D and the source S of the first semiconductor 11 When it is turned on, the electromagnetic coil of the relay 14 is supplied with voltage. The first contact K1 and the second contact K2 are conducted, that is, the first DC power source 310 supplies power to the load 200. If the main contact R of the first switch 60 is turned to The second contact U and the second DC power source 320 are not powered by the first terminal 30. At this time, the first DC power source 310 is not powered by the load 200.

As shown in FIG. 3, when the first terminal 30 is connected to the second DC power source 320, the first DC power source 310 supplies power to both ends of the load 200. If the load 200 is increased, the load 200 current is increased. If between the first contact K1 and the second contact K2 of the relay 14 When the voltage drop is greater than the base-emitter on-voltage of the second semiconductor 12, the collector C and the emitter E of the second semiconductor 12 are turned on, which is the same as that the gate G and the source S of the first semiconductor 11 are turned on, so the first The drain D and the source S of the semiconductor 11 are open-circuited, and the electromagnetic coil of the relay 14 is not supplied with voltage. The first contact K1 and the second contact K2 are open. The first DC power source 310 does not supply power to the load 200, and has reached The purpose of the current protection of the first DC power source 310.

As shown in FIG. 4, this is a second embodiment of the relay protection device of the present invention. As can be seen from the figure, the third semiconductor 15 is replaced by the second semiconductor 12 of FIG. 2, and the drain D of the third semiconductor 15 is replaced by the second semiconductor 12. The collector C, the source S of the third semiconductor 15 replaces the emitter E of the second semiconductor 12, and the gate G of the third semiconductor 15 replaces the base B of the second semiconductor 12. The photocoupler 16 is used as the gate fluid output. Type (Thyristor Output Type) replaces the phototransistor output type of the photocoupler 13 in FIG. 2. The input side of the photocoupler 16 is a light emitting diode (LED), and the output side is a gate fluid. The gate fluid has a first end. A1 and the second terminal A2, and other circuit components are the same as the relay protection device circuit 100 of the present invention in FIG.

As shown in FIG. 4, the positive electric terminal of the first DC power source 310 is supplied to the main contact R of the first switch 60 and one end of the load 200, and then the other end of the load 200 is connected to the second end 40. The main contact R of the switch 60 is turned to the first contact V. The positive electrical terminal of the first DC power source 310 is supplied to one of the first terminal 30 and the second resistor 22. The positive voltage is provided to the first resistor 21 to the first. The gate G of the semiconductor 11 and the drain D of the third semiconductor 15 are connected. Therefore, the drain D of the first semiconductor 11 is connected to the source S. The electromagnetic coil of the relay 14 is supplied with voltage. The first contact K1 is connected to the second contact. Point K2 is turned on, the first DC power source 300 supplies power to the load 200, and then the second resistor The other end of 22 is supplied from the anode terminal P to the cathode terminal N of the photocoupler 16. At this time, the first terminal A1 and the second terminal A2 of the photocoupler 16 are turned on, and the voltage of the gate G and the source S of the third semiconductor 15 is turned on. Low, so the drain D and the source S of the third semiconductor 15 are open; the second resistor 22 and the first capacitor 23 form a time constant circuit, which can control the conduction between the anode terminal P and the cathode terminal N of the photocoupler 16 Time to achieve the reset time control, its time constant circuit can be replaced with an equivalent function of the time controller without self-limiting.

As shown in FIG. 4, when the main contact R of the first switch 60 is turned to the second contact U, the first DC power source 310 does not supply power to the first terminal 30. At this time, the drain D of the first semiconductor 11 and the The source S is open, and the solenoid coil of the relay 14 has no voltage supply. The first contact K1 and the second contact K2 are open. The first DC power source 310 does not supply power to the load 200. The first end A1 of the photocoupler 16 and The second terminal A2 is open, and the gate G and the source S of the third semiconductor 15 have no voltage.

As shown in FIG. 4, when the main contact R of the first switch 60 is turned to the third contact T, the positive electric terminal of the second DC power source 320 supplies power to the first terminal 30 and the positive electric power of the first DC power source 300. The terminal is powered from the load 200 to the second terminal 40, and the negative terminal of the first DC power source 310 and the negative terminal of the second DC power source 320 are connected to the third terminal 50 because the second DC power source 320 is powered by the first terminal 30. At this time, the first terminal 30 supplies power to the gate G of the first resistor 21 to the first semiconductor 11 and the drain D of the third semiconductor 15. At this time, the drain D of the first semiconductor 11 and the source S are turned on, and the relay 14 The electromagnetic coil has a voltage supply, and its first contact K1 and the second contact K2 are turned on. The first DC power source 310 supplies power to the load 100, and then supplies power to the first end A1 of the photocoupler 16 through the second resistor 22. And the second terminal A2, at this time the first terminal A1 and the second terminal A2 of the photocoupler 16 When the gate G and the source S of the third semiconductor 15 are turned on, the drain D and the source S of the third semiconductor 15 are open.

As shown in FIG. 4, when the first terminal 30 is connected to the second DC power source 320, the first DC power source 310 supplies power to both ends of the load 200. If the two ends of the load 200 are short-circuited, it is equivalent to the first DC power source 310. A positive voltage is supplied to the first terminal A1 of the photocoupler 16. At this time, the drain D and the source S of the third semiconductor 15 are turned on, which is the same as that the gate G and the source S of the first semiconductor 11 are turned on. A semiconductor 11 has its drain D and its source S open, and the solenoid coil of the relay 14 has no voltage supply. Its first contact K1 and second contact K2 are open. The first DC power source 310 does not supply power to the load 200, but reaches Purpose of short circuit protection of the first DC power source 310.

As shown in FIG. 4, when the first terminal 30 is connected to the second DC power source 320, the first DC power source 310 supplies power to both ends of the load 200. When a short circuit occurs at the load 200, the cause of the short circuit at both ends of the load 200 is removed first. Then, the main contact R of the first switch 60 is turned to the second contact U and then to the third contact T. At this time, the first terminal A1 and the second terminal A2 of the photocoupler 16 are turned on, and the third semiconductor 15 The voltage across the gate G and the source S is low, the drain D of the third semiconductor 15 is open to the source S, and the gate G of the first semiconductor 11 receives a positive voltage, so the drain D and the source of the first semiconductor 11 are The pole S is turned on, and the electromagnetic coil of the relay 14 is supplied with voltage. The first contact K1 and the second contact K2 are turned on, that is, the first DC power source 310 supplies power to the load 200. If the first contact 60 is the main contact, R turns to the second contact U, and the second DC power source 320 is not powered by the first terminal 30. At this time, the first DC power source 310 is not powered by the load 200.

As shown in FIG. 4, when the first terminal 30 is connected to the second DC power source 320, the first DC power source 310 supplies power to both ends of the load 200. If the load 200 is increased, the load 200 current is increased. If When the voltage drop between the two points of the first contact K1 and the second contact K2 of the relay 14 is greater than the gate-source turn-on voltage of the third semiconductor 15, the drain D of the third semiconductor 15 and the source S are turned on, which is equivalent to the first The gate G and the source S of a semiconductor 11 are electrically connected to each other, so the drain D of the first semiconductor 11 and the source S are open, and the electromagnetic coil of the relay 14 has no voltage supply, and the first contact K1 and the second contact thereof K2 is open, and the first DC power source 310 does not supply power to the load 200, but achieves the purpose of protecting the first DC power source 310 from overcurrent.

As shown in FIG. 5, it is a third embodiment of the relay protection device of the present invention. As can be seen from the figure, the first terminal 30 in the relay protection device 100 of the present invention is connected to the main contact R of the first switch 60 and the second resistor 22. One end, the other end of the second resistor 22 is connected to the positive electrical end of the first capacitor 23, the negative electrical end of the first capacitor 23 is connected to the third end 50, and the third contact T of the first switch 60 is connected to the second DC power source 320 The positive terminal of the second DC power source 320 is connected to the third terminal 50, the second terminal 40 is connected to the positive terminal V + of the full-wave rectifier 17, and the third terminal 50 is connected to the negative terminal V- of the full-wave rectifier 17, The first AC terminal AC1 of the wave rectifier 17 is connected to the first contact K1 of the relay 14, the first contact K1 of the relay 14 is connected to the other end of the AC load 500, one end of the AC load 500 is connected to one end of the AC power supply 400, and the AC power supply 400 The other end is connected to the second contact K2 of the relay 14 and the second contact K2 of the relay 14 is connected to the second AC terminal AC2 of the full-wave rectifier 17. The combination of the above circuits constitutes a group of AC power 400 for overload or short circuit protection. Device.

As shown in FIG. 5, when the main contact R of the first switch 60 is turned to the third contact T, the positive electric terminal of the second DC power source 320 is supplied to the first terminal 30 and the negative electric terminal of the second DC power source 320 is supplied. Connect to the third terminal 50. At this time, the first terminal 30 supplies power to the first resistor 21 to the first half. The gate G of the conductor 11 is connected to the drain D of the first semiconductor 11 and the source S. The electromagnetic coil of the relay 14 is supplied with voltage. The first contact K1 and the second contact K2 are conducted. The AC power source 400 is powered by AC load 500.

As shown in FIG. 5, if the main contact R of the first switch 60 is turned to the second contact U, the second DC power source 320 does not supply power to the first terminal 30, and the gate G of the first semiconductor 11 has no voltage. When the drain D of the first semiconductor 11 and the source S are open, the solenoid coil of the relay 14 has no voltage supply, and the first contact K1 and the second contact K2 are open. The AC power source 400 does not supply power to the AC load 500.

As shown in FIG. 5, when the first terminal 30 is connected to the second DC power source 320, the AC power source 400 supplies power to the AC load 500. If the two ends of the AC load 500 are short-circuited, it is equivalent to passing the AC power source 400 through the full-wave rectifier 17. The positive voltage of the electric terminal V + is directly supplied to the second terminal 40. At this time, the collector C and the emitter E of the second semiconductor 12 are turned on, which is the same as that the gate G and the source S of the first semiconductor 11 are turned on, so the first The drain D and the source S of the semiconductor 11 are open, and the electromagnetic coil of the relay 14 has no voltage supply. The first contact K1 and the second contact K2 are open. The AC power source 400 is not supplied to the AC load 500 and reaches the AC load 500. Purpose of short circuit protection AC power supply 400.

As shown in FIG. 5, when the first terminal 30 is connected to the second DC power supply 320, the AC power supply 400 supplies power to both ends of the AC load 500. When the AC load 500 is short-circuited, the cause of the short-circuit at both ends of the AC load 500 is removed first. Then, the main contact R of the first switch 60 is turned to the second contact U, and then to the third contact T. At this time, the first terminal 30 supplies power to the gate G of the first resistor 21 to the first semiconductor 11, Therefore, the drain D and the source S of the first semiconductor 11 are conducted, and the electromagnetic coil of the relay 14 is supplied with a voltage. The first contact K1 and the second contact K1 The contact K2 is turned on, and the AC power source 400 supplies power to the AC load 500.

As shown in FIG. 5, when the first terminal 30 is connected to the second DC power source 320, the AC power source 400 supplies power to both ends of the AC load 500. If the AC load 500 is increased, the AC load 500 current is increased. If the voltage drop between the first contact K1 and the second contact K2 of the relay 14 passes through the full-wave rectifier 17 and the positive voltage of the positive terminal V + is greater than the base-emitter on-voltage of the second semiconductor 12, the second The collector C and the emitter E of the semiconductor 12 are turned on, and the gate G of the first semiconductor 11 and the both ends of the source S are turned on, so that the drain D and the source S of the first semiconductor 11 are open, and the electromagnetic coil of the relay 14 has no voltage. Supply, the first contact K1 and the second contact K2 are open, and the AC power source 400 does not supply power to the AC load 500, but achieves the purpose of protecting the AC power source 400 from overload of the AC load 500.

The inventor has been engaged in electronic technology research for more than 50 years. The examples of the present invention have proved their success through experiments and implementations, and can be implemented according to them. The above-mentioned examples are merely to fully illustrate the advantages of the present invention. In the embodiments, the protection scope of the present invention is not limited thereto, and equivalent substitutions or transformations made by those skilled in the art based on the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the scope of patent application.

Claims (10)

A relay protection device is characterized in that it is applied to a DC power circuit with a protection function when a load is overloaded or short-circuited. The relay protection device includes: a first semiconductor having a drain, a source, and a gate; Two semiconductors having a collector, an emitter, and a base, the collector is connected to the gate of the first semiconductor, the emitter is connected to the source of the first semiconductor; a first resistor has two connection ends The other end is connected to the gate of the first semiconductor and the collector of the second semiconductor. A photocoupler having an anode terminal, a cathode terminal, a collector, and an emitter, the emitter is connected to the base of the second semiconductor, and the cathode is connected to the emitter of the second semiconductor; and a relay having An electromagnetic coil, a first contact, and a second contact. A first end of the electromagnetic coil is connected to one end of the first resistor. A second end of the electromagnetic coil is connected to a drain of the first semiconductor. A contact is connected to the collector of the photocoupler, and the second contact is connected to the source of the first semiconductor. For example, the relay protection device of the first scope of the patent application, wherein the first semiconductor is an N-channel metal oxide semiconductor field effect transistor, and the second semiconductor is an N-type transistor or an N channel metal oxide semiconductor field effect transistor. For example, the relay protection device of the scope of patent application, wherein the photocoupler is a transistor output type or the photocoupler is a sluice output type. For example, the relay protection device of the first patent application diagram, wherein one end of the first resistor is connected to the main contact of the first switch and one end of the second resistor, and the main contact of the first switch is connected to the first contact. The positive terminal of the DC power supply and one end of the load. The other end of the load is connected to the relay. The first contact of the appliance, the negative electrical terminal of the DC power supply is connected to the second contact of the relay. For example, the relay protection device of the first patent application diagram, wherein the anode end of the photocoupler is connected to the other end of the second resistor and the positive electrical end of the first capacitor, and the negative electrical end of the first capacitor is connected to the photoelectricity. The cathode terminal of the coupler. For example, the relay protection device of item 4 of the patent application chart, wherein a first contact of the first switch is connected to a first DC power source, and a third contact of the first switch is connected to a second DC power source. For example, the relay protection device of item 5 of the patent application chart, wherein the second resistor and the first capacitor constitute a resistance-capacitance time constant circuit, which can control the conduction time between the anode terminal and the cathode terminal of the photocoupler or can be controlled by Equivalent time controller replacement. For example, the relay protection device of the first patent application diagram, wherein the first contact of the relay is connected to the other end of the AC load and the first AC end of the full-wave rectifier, and one end of the AC load is connected to one end of the AC power source. For example, the relay protection device of the first patent application diagram, wherein the second contact of the relay is connected to the second AC end of the full-wave rectifier and the other end of the AC power source. For example, the relay protection device of items 8 and 9 of the patent application diagram, wherein the positive electric terminal of the full-wave rectifier is connected to the collector of the photocoupler, the negative electric terminal of the full-wave rectifier is connected to the source of the first semiconductor, and A group of AC power source protection devices are formed in which the AC power source is overloaded or short-circuited in the AC load.