Circuit and method for eliminating electric spark generated by relay contact in working process

Abstract

The invention discloses a circuit and a method for eliminating electric sparks generated by relay contacts during working, belongs to the circuit control technology, and aims to solve the problem that the service life of a product is seriously affected due to the fact that the existing circuit using a relay to control a load to work forwards or backwards generates the sparks when the contacts of the relay are closed or released. A relay and a switch tube are connected in series in a load power supply loop; when a load is started, the relay is actuated firstly, and then the switch tube is turned on; when the load is stopped, the switching tube is firstly closed, and then the relay is released. Therefore, when the relay is closed and released, the switching tube is not connected with a loop, no current passes through the contact of the relay during action, and no electric spark is generated. The rated on-load 100,000-time electrical service life of the relay reaches 1,000,000-time mechanical service life, and the enabling service life of the relay is greatly prolonged.

Description

Technical Field

[0001] The invention belongs to circuit control technology, and in particular relates to a circuit and a method for eliminating electric sparks generated by relay contacts during operation. Background Art

[0002] A circuit that uses a relay to control the forward or reverse operation of a motor or motor-type load. Sparks will be generated when the relay contacts are energized or released, seriously affecting the service life of the product. Summary of the invention

[0003] The technical problem to be solved and the technical task proposed by the present invention is to overcome the defect that in the existing circuit using relays to control the forward or reverse operation of the load, sparks will be generated when the contacts of the relay are energized or released, which seriously affects the service life of the product, and to provide a circuit and method for eliminating the sparks generated by the relay contacts during operation, thereby improving the enabling life of the relay.

[0004] To achieve the above purpose, the circuit of the present invention for eliminating sparks generated by relay contacts during operation includes a relay connected in series in a load power supply circuit, and a switch tube for controlling the on and off of the entire load power supply circuit is also connected in series in the load power supply circuit.

[0005] Accordingly, when starting the load, the relay is first closed and then the switch is turned on; when stopping the load, the switch is first closed and then the relay is released. The switch can be a controllable device that can connect or disconnect a circuit, such as a MOS tube or a switch transistor.

[0006] When the relay is under rated load, the electrical life is generally 100,000 times, and the mechanical life is generally 1 million times. By adding a switching tube, the relay will not generate sparks when it is energized and released (because the switching tube is not connected to the circuit when the relay is energized and released, and no current flows through the contacts of the relay when it is in action, so no sparks are generated), directly bringing the electrical life of the relay to the level of its mechanical life, greatly improving the enabling life of the relay.

[0007] In one embodiment: there is one load; the relay includes a first relay and a second relay for changing the current direction of the load power supply circuit, the first relay and the second relay are connected in series in the load power supply circuit and are configured to change the current direction of the load power supply circuit by switching their working states.

[0008] Preferably: the first relay and the second relay each have a first pin, a second pin and a third pin, the first pin of each relay is connected to the load power supply circuit, and each relay changes its state of attraction and release so that its second pin and third pin are selectively connected to its first pin to be connected to the load power supply circuit.

[0009] In another embodiment: the load includes a first load and a second load; the relay includes a first relay and a second relay for changing the current direction of the load power supply circuit and a third relay for selectively switching the first load and the second load to the load power supply circuit, the first relay and the second relay are connected in series in the load power supply circuit and are configured to change the current direction of the load power supply circuit by switching their working states, and the third relay is connected in series in the load power supply circuit and is configured to selectively switch the first load and the second load to the load power supply circuit by switching its working states.

[0010] Preferably: the first relay, the second relay and the third relay all have a first pin, a second pin and a third pin, the first pin of each relay is connected to the load power supply circuit, and each relay changes its state of attraction and release so that its second pin and third pin are selectively connected to its first pin to be connected to the load power supply circuit.

[0011] Optionally, each relay is a normally open relay or a normally closed relay.

[0012] Preferably: the switch tube is connected in series at the end of the current flow direction of the load power supply loop.

[0013] Preferably: a diode is connected to the load power supply circuit, and the diode absorbs the reverse induced electromotive force generated by the internal coil of the load when the load stops.

[0014] Preferably: according to the current direction of the load when it is working, the positive electrode of the diode is connected to the front end of the switch tube, and the negative electrode of the diode is connected to the load power supply. When the switch tube disconnects the load power supply circuit, no matter what the direction of the load working current is, the diode can always establish a reverse induced electromotive force absorption circuit to absorb the reverse induced electromotive force generated by the internal coil of the load.

[0015] The method of eliminating the electric sparks generated by the relay contacts during operation of the present invention is to connect the relay and the switch tube in series in the load power supply circuit; when starting the load, the relay is firstly attracted, and then the switch tube is turned on; when stopping the load, the switch tube is firstly turned off, and then the relay is released. Therefore, when the relay is attracted and released, the switch tube is not connected to the circuit, and no current flows through the contacts of the relay when it is in action, and no electric sparks are generated.

[0016] When the relay is under rated load, the electrical life is generally 100,000 times, and the mechanical life is generally 1 million times. By adding a switching tube, the relay will not generate sparks when it is energized and released, and the electrical life of the relay can be directly extended to the level of mechanical life, greatly improving the enabling life of the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a circuit diagram of embodiment 1 of the present invention;

[0018] Figure 2 It is a schematic diagram of a load power supply circuit being switched to a current direction according to Embodiment 1 of the present invention;

[0019] Figure 3 It is a schematic diagram of a load power supply circuit being switched to another current direction according to Embodiment 1 of the present invention;

[0020] Figure 4 is a circuit diagram of embodiment 2 of the present invention;

[0021] Figure 5 This is a schematic diagram of switching a first load to a load power supply circuit and operating in a current direction according to Embodiment 2 of the present invention;

[0022] Figure 6 This is a schematic diagram of switching the first load to the load power supply circuit and operating in another current direction according to Embodiment 2 of the present invention;

[0023] Figure 7 This is a schematic diagram of switching the second load to the load power supply circuit and operating in one current direction according to Embodiment 2 of the present invention;

[0024] Figure 8 This is a schematic diagram of switching the second load to the load power supply circuit and operating in another current direction according to Embodiment 2 of the present invention;

[0025] Description of the numbers in the figure:

[0026] 100 load, 110 first load, 120 second load;

[0027] 210 first relay, 211 first foot, 212 second foot, 212 third foot;

[0028] 220 second relay, 221 first foot, 222 second foot, 223 third foot;

[0029] 230 the third relay, 231 the first foot, 232 the second foot, 233 the third foot;

[0030] 300 switch tube;

[0031] 400 diodes. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusions. For example, a method or product comprising a series of technical features is not necessarily limited to those technical features clearly listed, but may also include other technical features that are not clearly listed and can be included in the method or product.

[0034] In the description of the present invention, it is necessary to understand that the technical features defined by the terms "first", "second" and the like with sequential concepts are only for the purpose of clearly describing the defined technical features so that the defined technical features can be clearly distinguished from other technical features, but do not represent such naming in actual implementation, and therefore cannot be understood as a limitation of the present invention.

[0035] The present invention is described in detail below in conjunction with specific embodiments and accompanying drawings.

[0036] Example 1

[0037] like Figure 1-3 The circuit for eliminating the sparks generated by the relay contacts during operation shown in the figure has one load 100, and a first relay 210, a second relay 220 and a switch tube 300 are connected in series in the load power supply circuit, and the first relay 210 and the second relay 220 are configured to change the current direction of the load power supply circuit by switching their working states. The switch tube 300 controls the on and off of the entire load power supply circuit. In this embodiment, the switch tube 300 is a switch transistor. In other embodiments, the switch transistor can be replaced by a controllable device such as a MOS tube that has the function of connecting or disconnecting a circuit.

[0038] Specifically, the first relay 210 has a first pin 211, a second pin 212 and a third pin 213, and the second relay 220 has a first pin 221, a second pin 222 and a third pin 223. The first pin of each relay is connected to the load power supply circuit, and each relay changes its state of attraction and release so that its second pin and third pin are selectively connected to its first pin to be connected to the load power supply circuit.

[0039] In the figure, the switch tube 300 is connected in series at the end of the current flow direction of the load power supply loop.

[0040] In this embodiment, each relay is a normally open relay. When the first relay 210 is in the default state, the first pin 211 is connected to the second pin 212, and the first pin 211 is disconnected from the third pin 212; when the first relay 210 is in the attracted state, the first pin 211 is connected to the third pin 212, and the first pin 211 is disconnected from the second pin 212. When the second relay 220 is in the default state, the first pin 221 is connected to the second pin 222, and the first pin 221 is disconnected from the third pin 223; when the second relay 220 is in the attracted state, the first pin 221 is connected to the third pin 223, and the first pin 221 is disconnected from the second pin 222. In view of the fact that the relay switches the circuit by its attraction and release, in other embodiments, the normally open relay can be replaced by connecting the circuit with a normally closed relay and changing its wiring and control method.

[0041] Figure 1-3 In the figure, VCC is the load power supply, VDD is the relay working power supply, GND is grounding, R is a resistor, + is the positive pole of the load power supply, - is the negative pole of the load power supply, S, D, G are the three pins of the switching transistor, and P RY controls the corresponding relay to be attracted and released.

[0042] like Figure 2 As shown, when the load 100 is to be started, the first relay 210 is first set to the default state (normally open state), the second relay 220 is set to the energized state, and then the switch tube 300 is turned on, the load power supply circuit is connected, and the load working current direction is negative (-) on the left and positive (+) on the right. When the load is to be stopped, the switch tube 300 is first turned off, and then the first relay 210 is set to the default state (normally open state), and the second relay 220 is set to the default state (normally open state), the load power supply circuit is disconnected by the second relay, and the load 100 stops working. Figure 2 In the figure, the single-dotted line represents the connected load power supply circuit.

[0043] like Figure 3 As shown, when the load 100 is to be started, the first relay 210 is first placed in the energized state, the second relay 220 is placed in the default state (normally open state), and then the switch tube 300 is turned on, the load power supply circuit is connected, and the load working current direction is positive (+) on the left and negative (-) on the right. When the load is to be stopped, the switch tube 300 is first turned off, and then the first relay 210 is placed in the default state (normally open state), and the second relay 220 is placed in the default state (normally open state), the load power supply circuit is disconnected by the first relay, and the load 100 stops working. Figure 3 In the figure, the single-dotted line represents the connected load power supply circuit.

[0044] As mentioned above, Figure 2 The working current direction of the medium load 100 is Figure 3 The working current direction of the medium load 100 is opposite.

[0045] Therefore, by switching the closing and releasing states of the first relay 210 and the second relay 220 , the current direction of the load power supply circuit can be changed, so that the load 100 can be switched to work (such as changing the direction of the motor).

[0046] As mentioned above, when the relay is energized or released, the switch tube does not connect the circuit, and no current flows through the contacts of the relay when it is in action, so no electric sparks are generated, which increases the enabling life of the relay.

[0047] Furthermore, when the switch tube 300 is turned off to stop the load, the internal coil of the load 100 will generate a reverse induced electromotive force, which is unfavorable to the switch tube 300. In order to eliminate this disadvantage, a diode 400 is connected to the load power supply circuit, specifically, the positive electrode of the diode 400 is connected between the second relay 220 and the switch tube 300, and the negative electrode of the diode 400 is connected to the load power supply. When the switch tube 300 is turned off to stop the load, no matter what the direction of the load working current is, the diode can always establish an absorption circuit of the reverse induced electromotive force to absorb the reverse induced electromotive force generated by the internal coil of the load. Therefore, the connection position of the diode should be suitable for the load to change the direction of the working current, and to establish an absorption circuit of the reverse induced electromotive force. According to the current direction when the load is working, it is appropriate for the positive electrode of the diode 400 to be connected to the front end of the switch tube 300.

[0048] Example 2

[0049] like Figure 4-8 The circuit for eliminating the sparks generated by the relay contacts during operation shown in the figure includes a first load 110 and a second load 120; the relay includes a first relay 210 and a second relay 220 for changing the current direction of the load power supply circuit and a third relay 230 for selectively switching the first load 110 and the second load 120 to the load power supply circuit. The first relay 210 and the second relay 220 are connected in series in the load power supply circuit and are configured to change the current direction of the load power supply circuit by switching their working states; the third relay 230 is connected in series in the load power supply circuit and is configured to selectively switch the first load 110 and the second load 120 to the load power supply circuit by switching its working state; and the switch tube 300 is connected in series in the load power supply circuit to control the on and off of the entire load power supply circuit. In this embodiment, the switch tube 300 is a switch transistor. In other embodiments, the switch transistor can be replaced by a controllable device with a circuit connected or disconnected, such as a MOS tube.

[0050] Specifically, the first relay 210 has a first pin 211, a second pin 212 and a third pin 213, the second relay has a first pin 221, a second pin 222 and a third pin 223, and the third relay 230 has a first pin 231, a second pin 232 and a third pin 233. The first pin of each relay is connected to the load power supply circuit, and each relay changes its state of attraction and release so that its second pin and third pin are selectively connected to its first pin to connect to the load power supply circuit.

[0051] In the figure, the switch tube 300 is connected in series at the end of the current flow direction of the load power supply loop.

[0052] In this embodiment, each relay is a normally open relay. When the first relay 210 is in the default state, the first pin 211 is connected to the second pin 212, and the first pin 211 is disconnected from the third pin 212; when the first relay 210 is in the attracted state, the first pin 211 is connected to the third pin 212, and the first pin 211 is disconnected from the second pin 212. When the second relay 220 is in the default state, the first pin 221 is connected to the second pin 222, and the first pin 221 is disconnected from the third pin 223; when the second relay 220 is in the attracted state, the first pin 221 is connected to the third pin 223, and the first pin 221 is disconnected from the second pin 222. When the third relay 230 is in the default state, the first pin 231 is connected to the second pin 232, and the first pin 231 is disconnected from the third pin 232; when the third relay 230 is in the attracted state, the first pin 231 is connected to the third pin 232, and the first pin 231 is disconnected from the second pin 232.

[0053] Since the relay switches the circuit by its closure and release, in other embodiments, the normally open relay can be replaced by connecting the normally closed relay to the circuit and changing its wiring and control method.

[0054] Figure 4-8 In the figure, VCC is the load power supply, VDD is the relay working power supply, GND is grounding, R is a resistor, + is the positive pole of the load power supply, - is the negative pole of the load power supply, S, D, and G are the three pins of the switch tube, and P RY controls the corresponding relay to be attracted and released.

[0055] like Figure 5-6 As shown, the third relay 230 is in the energized state, the first load 110 is switched into the load power supply circuit, and the second load 120 is switched out of the load power supply circuit.

[0056] like Figure 5As shown, when the first load 110 is to be started, the first relay 210 is first set to the default state (normally open state), the second relay 220 is set to the energized state, and then the switch tube 300 is turned on, the load power supply circuit is connected, and the load working current direction is negative (-) at the top and positive (+) at the bottom. When the first load 110 is to be stopped, the switch tube 300 is first turned off, and then the first relay 210 is set to the default state (normally open state), the second relay 220 is set to the default state (normally open state), the load power supply circuit is disconnected by the second relay 220, and the first load 110 stops working. Figure 5 In the figure, the single-dotted line represents the connected load power supply circuit.

[0057] like Figure 6 As shown, when the first load 110 is to be started, the first relay 210 is first placed in the energized state, the second relay 220 is placed in the default state (normally open state), and then the switch tube 300 is turned on, the load power supply circuit is connected, and the load working current direction is positive (+) at the top and negative (-) at the bottom. When the first load 110 is to be stopped, the switch tube 300 is first turned off, and then the first relay 210 is placed in the default state (normally open state), the second relay 220 is placed in the default state (normally open state), the load power supply circuit is disconnected by the first relay 210, and the first load 110 stops working. Figure 6 In the figure, the single-dotted line represents the connected load power supply circuit.

[0058] As mentioned above, Figure 5 The working current direction of the first load 110 is Figure 6 The working current direction of the first load 110 is opposite.

[0059] like Figure 7-8 As shown, the third relay 230 is in a default state (normally open state), the second load 120 is switched into the load power supply circuit, and the first load 110 is switched out of the load power supply circuit.

[0060] like Figure 7 As shown, when the second load 120 is to be started, the first relay 210 is first set to the default state (normally open state), the second relay 220 is set to the energized state, and then the switch tube 300 is turned on, the load power supply circuit is connected, and the working current direction of the second load 120 is negative (-) at the top and positive (+) at the bottom. When the second load 120 is to be stopped, the switch tube 300 is first turned off, and then the first relay 210 is set to the default state (normally open state), and the second relay 220 is set to the default state (normally open state), the load power supply circuit is disconnected by the second relay 220, and the second load 120 stops working. Figure 7 In the figure, the single-dotted line represents the connected load power supply circuit.

[0061] like Figure 8As shown, when the second load 120 is to be started, the first relay 210 is first placed in the energized state, the second relay 220 is placed in the default state (normally open state), and then the switch tube 300 is turned on, the load power supply circuit is connected, and the working current direction of the second load 120 is positive (+) at the top and negative (-) at the bottom. When the second load 120 is to be stopped, the switch tube 300 is first turned off, and then the first relay 210 is placed in the default state (normally open state), and the second relay 220 is placed in the default state (normally open state), the load power supply circuit is disconnected by the first relay 210, and the second load 120 stops working. Figure 8 In the figure, the single-dotted line represents the connected load power supply circuit.

[0062] As mentioned above, Figure 7 The working current direction of the second load 120 is Figure 8 The working current direction of the second load 120 is opposite.

[0063] Therefore, by switching the third relay on and off, the first load and the second load can be switched to the load power supply circuit. By switching the first relay and the second relay on and off, the current direction of the load power supply circuit can be changed, so that the load can be switched (such as changing the direction of the motor).

[0064] As mentioned above, when the relay is energized or released, the switch tube does not connect the circuit, and no current flows through the contacts of the relay when it is in action, so no electric sparks are generated, which increases the enabling life of the relay.

[0065] In this embodiment, when the switch tube 300 is turned off to stop the first load or the second load, the internal coils of the first load and the second load will generate reverse induced electromotive force, which is unfavorable to the switch tube 300. In order to eliminate this disadvantage, the load power supply circuit is connected with a diode 400, specifically, the positive electrode of the diode 400 is connected between the second relay 220 and the switch tube, and the negative electrode of the diode 400 is connected to the load power supply. When the switch tube 300 is turned off to stop the first load or the second load, no matter what the direction of the working current of the first load or the second load is, the diode can always establish an absorption circuit of the reverse induced electromotive force to absorb the reverse induced electromotive force generated by the internal coil of the first load or the second load. Therefore, the connection position of the diode should be suitable for the first load and the second load to change the working current direction, and to establish an absorption circuit of the reverse induced electromotive force. According to the current direction of the first load and the second load when working, it is appropriate for the positive electrode of the diode 400 to be connected to the front end of the switch tube 300.

Claims

1. A circuit for eliminating sparks generated by relay contacts during operation, comprising a relay connected in series in a load power supply circuit, characterized in that: A switch tube (300) for controlling the on / off of the entire load power supply circuit is also connected in series in the load power supply circuit.

2. The circuit according to claim 1, characterized in that: There is one load (100); the relay comprises a first relay (210) and a second relay (220) for changing the current direction of the load power supply circuit; the first relay and the second relay are connected in series in the load power supply circuit and are configured to change the current direction of the load power supply circuit by switching their working states.

3. The circuit according to claim 2, characterized in that: The first relay (210) and the second relay (220) both have a first pin, a second pin and a third pin. The first pin of each relay is connected to a load power supply circuit. As the state of each relay is changed between being attracted and released, the second pin and the third pin of each relay are selectively connected to the first pin to be connected to the load power supply circuit.

4. The circuit according to claim 1, characterized in that: The load comprises a first load (110) and a second load (120); the relay comprises a first relay (210) and a second relay (220) for changing the current direction of a load power supply circuit, and a third relay (230) for selectively switching the first load and the second load to the load power supply circuit, the first relay and the second relay are connected in series in the load power supply circuit and are configured to change the current direction of the load power supply circuit by switching their working states, and the third relay is connected in series in the load power supply circuit and is configured to selectively switch the first load and the second load to the load power supply circuit by switching its working state.

5. The circuit according to claim 4, characterized in that: The first relay (210), the second relay (220) and the third relay (230) all have a first pin, a second pin and a third pin. The first pin of each relay is connected to a load power supply circuit. As the state of each relay is changed between being attracted and released, the second pin and the third pin of each relay are selectively connected to the first pin to be connected to the load power supply circuit.

6. The circuit according to any one of claims 1 to 5, characterized in that: Each relay is either a normally open relay or a normally closed relay.

7. The circuit according to any one of claims 1 to 5, characterized in that: The switch tube is connected in series at the end of the load power supply loop where the current flows.

8. The circuit according to any one of claims 1 to 5, characterized in that: The load power supply circuit is connected to a diode (400), and the diode (400) absorbs the reverse induced electromotive force generated by the coil inside the load when the load stops.

9. The circuit according to claim 8, characterized in that: According to the current direction when the load is working, the anode of the diode (400) is connected to the front end of the switch tube (300), and the cathode of the diode (400) is connected to the load power supply.

10. A method for eliminating sparks generated by relay contacts during operation, characterized in that: A relay and a switch tube are connected in series in the load power supply circuit; when starting the load, the relay is first closed and then the switch tube is turned on; when stopping the load, the switch tube is first closed and then the relay is released.

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