Contactor contact adhesion protection circuit for positive and negative rotation of motor
By designing the contact sticking protection circuit for the front and reverse motor, using the cooperation of the intermediate relay and switch, the motor failure and safety accidents caused by the contact sticking of the contacts are solved, and the normal operation and use of the motor are achieved.
Patent Information
- Application Number
- CN202421320856.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-11
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-06-11
AI Technical Summary
In the motor forward and reverse control, the contactor contacts are prone to sticking due to frequent use and harsh environments, which causes the motor to fail to stop or reverse normally, and may even cause safety accidents.
A contact sticking protection circuit for contacts with forward and reverse rotation of the motor is designed. Through the combination of the main circuit and the control circuit, the intermediate relay and the switch are used to ensure that the intermediate relay cannot be turned on when the contacts are stuck, thereby preventing phase-to-phase short circuits.
It effectively prevents motor failure and safety accidents caused by the adhesion of contacts, and ensures the normal operation and safety of the motor.
Smart Images
Figure CN222654812U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of motor control, in particular to a contact point adhesion protection circuit for a contactor of a motor in forward and reverse rotation. Background Art
[0002] The forward and reverse control of the motor actually changes the direction of rotation of the motor. When the motor rotates forward, the output shaft rotates in a certain direction, and when it rotates reversely, it rotates in the opposite direction. The forward and reverse rotation of the motor is widely used in daily use, such as cranes, electric planers for woodworking, bench drills, wire cutters, spin dryers and lathes. Initially, people needed to replace the motor wires to reverse some equipment, but this method was cumbersome in actual use.
[0003] With the birth of contactors, the forward and reverse circuits of motors have also been further developed. At present, the forward and reverse rotation of motors is generally controlled by using two contactors to form a circuit. This method avoids the need to replace the motor wires for the initial reversal, and can control the forward and reverse rotation of the motor more flexibly and conveniently. However, the two contactors cannot be attracted at the same time. If they are attracted at the same time, a short circuit accident of the power supply will occur. In order to prevent such accidents, an interlocking protection circuit is added to the circuit so that the two contactors will not be attracted at the same time, realizing low voltage and long-distance frequent control.
[0004] However, in actual production work, due to frequent overload of the starting motor, the contactor contacts are worn and oxidized, or the contactor is exposed to high temperature, humidity, dust and other harsh working environments for too long, the contactor contacts may become stuck. When the contactor contacts stick, the motor may not be able to stop or reverse start to cause a phase-to-phase short circuit, thereby damaging the motor and even causing a safety accident. Summary of the invention
[0005] An embodiment of the utility model provides a contactor contact adhesion protection circuit for forward and reverse rotation of a motor, comprising a main circuit and a control circuit, wherein the main circuit comprises a first contactor electrically connected to a three-phase AC power supply, a second contactor and a third contactor electrically connected to the first contactor respectively, and the second contactor and the third contactor are electrically connected to the motor respectively; the control circuit comprises an intermediate relay, a first switch and a second switch, wherein only one of the first switch and the second switch is closed at the same time, and the closure of any switch can control the intermediate relay to be turned on, and after the intermediate relay is turned on, it controls the first contactor, the second contactor to be turned on, or the first contactor, the third contactor to be turned on with different switches.
[0006] In one possible implementation, the first end of the normally open contact of the first contactor is electrically connected to the three-phase AC power supply, the second end of the normally open contact of the first contactor is electrically connected to the first end of the normally open contact of the second contactor and the first end of the normally open contact of the third contactor, respectively, and the second end of the normally open contact of the second contactor and the second end of the normally open contact of the third contactor are electrically connected to the motor, respectively.
[0007] In a possible implementation, a first end of the first normally open contact of the intermediate relay is electrically connected to the three-phase AC power supply, a second end of the first normally open contact of the intermediate relay is electrically connected to a first end of the coil of the first contactor, and a second end of the coil of the first contactor is electrically connected to the three-phase AC power supply;
[0008] The first end of the first switch is electrically connected to the three-phase AC power supply, the second end of the first switch is electrically connected to the first end of the second normally open contact of the intermediate relay, the first end of the first normally closed contact of the first contactor and the first end of the third normally open contact of the intermediate relay, the second end of the second normally open contact of the intermediate relay is electrically connected to the first end of the second normally closed contact of the third contactor, the second end of the second normally closed contact of the third contactor is electrically connected to the first end of the coil of the second contactor, and the second end of the coil of the second contactor is electrically connected to the three-phase AC power supply;
[0009] The second end of the first normally closed contact of the first contactor is electrically connected to the first end of the first normally closed contact of the second contactor, the second end of the first normally closed contact of the second contactor is electrically connected to the first end of the first normally closed contact of the third contactor, the second end of the first normally closed contact of the third contactor is electrically connected to the second end of the third normally open contact of the intermediate relay and the first end of the coil of the intermediate relay, respectively, and the second end of the coil of the intermediate relay is electrically connected to the three-phase AC power supply;
[0010] A first end of the second switch is electrically connected to the three-phase AC power supply, a second end of the second switch is electrically connected to a first end of a first normally closed contact of the first contactor, a first end of a third normally open contact of the intermediate relay, and a first end of a fourth normally open contact of the intermediate relay, respectively, a second end of the fourth normally open contact of the intermediate relay is electrically connected to a first end of a second normally closed contact of the second contactor, a second end of the second normally closed contact of the second contactor is electrically connected to a first end of a coil of the third contactor, and a second end of the coil of the third contactor is electrically connected to the three-phase AC power supply.
[0011] In a possible implementation, a circuit breaker is provided between the three-phase AC power supply and the first contactor, the input terminal of the circuit breaker is electrically connected to the three-phase AC power supply, and the output terminal of the circuit breaker is electrically connected to the first end of the normally open contact of the first contactor.
[0012] The utility model controls the conduction of the intermediate relay by closing the first switch or the second switch. After the intermediate relay is turned on, it controls the conduction of the first contactor and the second contactor or the conduction of the first contactor and the third contactor with different switches to control the forward or reverse rotation of the motor. When the contacts of the first contactor, the second contactor and the third contactor are stuck, pressing the first switch or the second switch cannot turn on the intermediate relay, thus realizing the protection of the forward and reverse rotation circuit of the motor and avoiding safety accidents such as phase short circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 A schematic diagram of a contactor contact adhesion protection circuit structure for a motor forward and reverse rotation provided by an embodiment of the utility model;
[0014] Figure 1 The symbols are: KM1-first contactor, KM2-second contactor, KM3-third contactor, M1-motor, QF1-circuit breaker, SB1-first switch, SB2-second switch, KA1-intermediate relay, KA1-1-first normally open contact of intermediate relay, KA1-2-second normally open contact of intermediate relay, KA1-3-third normally open contact of intermediate relay, KA1-4-fourth normally open contact of intermediate relay, KM1-4-first normally closed contact of first contactor, KM2-4-first normally closed contact of second contactor, KM2-5-second normally closed contact of second contactor, KM3-4-first normally closed contact of third contactor, KM3-5-second normally closed contact of third contactor. DETAILED DESCRIPTION
[0015] The present solution is described below in conjunction with the accompanying drawings and specific implementation methods.
[0016] Figure 1 A schematic diagram of a contactor contact adhesion protection circuit structure for a motor forward and reverse rotation provided by the utility model, see Figure 1, the utility model embodiment includes a main circuit and a control circuit, the main circuit includes a first contactor KM1 electrically connected to a three-phase AC power supply, a second contactor KM2 and a third contactor KM3 electrically connected to the first contactor KM1 respectively, the second contactor KM2 and the third contactor KM3 are electrically connected to the motor M1 respectively; the control circuit includes an intermediate relay KA1, a first switch SB1 and a second switch SB2, only one of the first switch SB1 and the second switch SB2 is closed at the same time, and any switch closure can control the intermediate relay KA1 to be turned on, and after the intermediate relay KA1 is turned on, it controls the first contactor KM1, the second contactor KM2 to be turned on or the first contactor KM1, the third contactor KM3 to be turned on with different switches. In this embodiment, when the first switch SB1 is pressed, the intermediate relay KA1 will be turned on, and then the first contactor KM1 and the second contactor KM2 are turned on to control the forward rotation of the motor; or, when the second switch SB2 is pressed, the intermediate relay KA1 will be turned on, and then the first contactor KM1 and the third contactor KM3 are turned on to control the reverse rotation of the motor.
[0017] Furthermore, the first end of the normally open contact of the first contactor KM1 is electrically connected to the three-phase AC power supply, the second end of the normally open contact of the first contactor KM1 is electrically connected to the first end of the normally open contact of the second contactor KM2 and the first end of the normally open contact of the third contactor KM3, respectively, and the second end of the normally open contact of the second contactor KM2 and the second end of the normally open contact of the third contactor KM3 are electrically connected to the motor M1, respectively.
[0018] Further, the first end of the first normally open contact KA1-1 of the intermediate relay is electrically connected to the three-phase AC power supply, the second end of the first normally open contact KA1-1 of the intermediate relay is electrically connected to the first end of the coil of the first contactor KM1, and the second end of the coil of the first contactor KM1 is electrically connected to the three-phase AC power supply;
[0019] A first end of the first switch SB1 is electrically connected to the three-phase AC power supply, a second end of the first switch SB1 is electrically connected to a first end of the second normally open contact KA1-2 of the intermediate relay, a first end of the first normally closed contact KM1-4 of the first contactor and a first end of the third normally open contact KA1-3 of the intermediate relay, a second end of the second normally open contact KA1-2 of the intermediate relay is electrically connected to a first end of the second normally closed contact KM3-5 of the third contactor, a second end of the second normally closed contact KM3-5 of the third contactor is electrically connected to a first end of the coil of the second contactor KM2, and a second end of the coil of the second contactor KM2 is electrically connected to the three-phase AC power supply;
[0020] The second end of the first normally closed contact KM1-4 of the first contactor is electrically connected to the first end of the first normally closed contact KM2-4 of the second contactor, the second end of the first normally closed contact KM2-4 of the second contactor is electrically connected to the first end of the first normally closed contact KM3-4 of the third contactor, the second end of the first normally closed contact KM3-4 of the third contactor is electrically connected to the second end of the third normally open contact KA1-3 of the intermediate relay and the first end of the coil of the intermediate relay KA1, respectively, and the second end of the coil of the intermediate relay KA1 is electrically connected to the three-phase AC power supply;
[0021] The first end of the second switch SB2 is electrically connected to the three-phase AC power supply, and the second end of the second switch SB2 is electrically connected to the first end of the first normally closed contact KM1-4 of the first contactor, the first end of the third normally open contact KA1-3 of the intermediate relay and the first end of the fourth normally open contact KA1-4 of the intermediate relay, respectively, the second end of the fourth normally open contact KA1-4 of the intermediate relay is electrically connected to the first end of the second normally closed contact KM2-5 of the second contactor, the second end of the second normally closed contact KM2-5 of the second contactor is electrically connected to the first end of the coil of the third contactor KM3, and the second end of the coil of the third contactor KM3 is electrically connected to the three-phase AC power supply.
[0022] In this embodiment, when the first switch SB1 is pressed, the coil of the intermediate relay KA1 is energized, the first normally open contact KA1-1 of the intermediate relay, the second normally open contact KA1-2 of the intermediate relay, the third normally open contact KA1-3 of the intermediate relay and the fourth normally open contact KA1-4 of the intermediate relay are closed, the coil of the first contactor KM1 and the coil of the second contactor KM2 are energized, the normally open contact of the first contactor KM1 and the normally open contact of the second contactor KM2 are closed, the first normally closed contact KM1-4 of the first contactor, the first normally closed contact KM2-4 of the second contactor and the second normally closed contact KM2-5 of the second contactor are disconnected, and the motor M1 rotates forward at this time. Because the coil of the third contactor KM3 is connected in series with the second normally closed contact KM2-5 of the second contactor, even if the second switch SB2 is pressed at this time, the coil of the third contactor KM3 will not be energized.
[0023] When the second switch SB2 is pressed, the coil of the intermediate relay KA1 is energized, the first normally open contact KA1-1 of the intermediate relay, the second normally open contact KA1-2 of the intermediate relay, the third normally open contact KA1-3 of the intermediate relay and the fourth normally open contact KA1-4 of the intermediate relay are closed, the coil of the first contactor KM1 and the coil of the third contactor KM3 are energized, the normally open contact of the first contactor KM1 and the normally open contact of the third contactor KM3 are closed, the first normally closed contact KM1-4 of the first contactor, the first normally closed contact KM3-4 of the third contactor and the second normally closed contact KM3-5 of the third contactor are disconnected, and the motor M1 is reversed at this time. Because the coil of the second contactor KM2 is connected in series with the second normally closed contact KM3-5 of the third contactor, even if the first switch SB1 is pressed at this time, the coil of the second contactor KM2 will not be energized, thus realizing the interlocking of the second contactor KM2 and the third contactor KM3.
[0024] Since all the contacts of the contactor are fixed on the armature, the normally closed contact acts together with the normally open contact. When the normally open contacts of one or more of the first contactor KM1, the second contactor KM2 and the third contactor KM3 are stuck, one or more of the corresponding KM1-4, KM2-4, and KM3-4 are disconnected. At this time, no matter whether the first switch SB1 or the second switch SB2 is pressed, the coil of the intermediate relay KA1 cannot be energized. Then, the coils of the three contactors KM1, KM2 and KM3 are not energized, and the entire circuit is in a disconnected state, thereby realizing the contactor contact adhesion protection for the forward and reverse rotation of the motor.
[0025] In this embodiment, a circuit breaker QF1 is provided between the three-phase AC power supply and the first contactor KM1, the inlet terminal of the circuit breaker QF1 is electrically connected to the three-phase AC power supply, and the outlet terminal of the circuit breaker QF1 is electrically connected to the first end of the normally open contact of the first contactor KM1. The circuit breaker protects the power supply line and the motor, and can automatically cut off the circuit when a serious overload or short circuit or undervoltage fault occurs. Its function is equivalent to a combination of a fuse switch and an over-underheating relay.
[0026] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.
[0027] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A contactor contact adhesion protection circuit for motor forward and reverse rotation, characterized in that: The invention comprises a main circuit and a control circuit, wherein the main circuit comprises a first contactor electrically connected to a three-phase AC power supply, a second contactor and a third contactor electrically connected to the first contactor respectively, and the second contactor and the third contactor are electrically connected to a motor respectively; the control circuit comprises an intermediate relay, a first switch and a second switch, wherein only one of the first switch and the second switch is closed at the same time, and any switch closure can control the intermediate relay to be turned on, and after the intermediate relay is turned on, it controls the first contactor, the second contactor to be turned on, or the first contactor, the third contactor to be turned on with different switches.
2. The contactor contact adhesion protection circuit for motor forward and reverse rotation according to claim 1, characterized in that: The first end of the normally open contact of the first contactor is electrically connected to the three-phase AC power supply, the second end of the normally open contact of the first contactor is electrically connected to the first end of the normally open contact of the second contactor and the first end of the normally open contact of the third contactor, respectively, and the second end of the normally open contact of the second contactor and the second end of the normally open contact of the third contactor are electrically connected to the motor, respectively.
3. The contactor contact adhesion protection circuit for motor forward and reverse rotation according to claim 1, characterized in that: A first end of the first normally open contact of the intermediate relay is electrically connected to the three-phase AC power supply, a second end of the first normally open contact of the intermediate relay is electrically connected to a first end of the coil of the first contactor, and a second end of the coil of the first contactor is electrically connected to the three-phase AC power supply; The first end of the first switch is electrically connected to the three-phase AC power supply, the second end of the first switch is electrically connected to the first end of the second normally open contact of the intermediate relay, the first end of the first normally closed contact of the first contactor and the first end of the third normally open contact of the intermediate relay, the second end of the second normally open contact of the intermediate relay is electrically connected to the first end of the second normally closed contact of the third contactor, the second end of the second normally closed contact of the third contactor is electrically connected to the first end of the coil of the second contactor, and the second end of the coil of the second contactor is electrically connected to the three-phase AC power supply; The second end of the first normally closed contact of the first contactor is electrically connected to the first end of the first normally closed contact of the second contactor, the second end of the first normally closed contact of the second contactor is electrically connected to the first end of the first normally closed contact of the third contactor, the second end of the first normally closed contact of the third contactor is electrically connected to the second end of the third normally open contact of the intermediate relay and the first end of the coil of the intermediate relay, respectively, and the second end of the coil of the intermediate relay is electrically connected to the three-phase AC power supply; A first end of the second switch is electrically connected to the three-phase AC power supply, a second end of the second switch is electrically connected to a first end of a first normally closed contact of the first contactor, a first end of a third normally open contact of the intermediate relay, and a first end of a fourth normally open contact of the intermediate relay, respectively, a second end of the fourth normally open contact of the intermediate relay is electrically connected to a first end of a second normally closed contact of the second contactor, a second end of the second normally closed contact of the second contactor is electrically connected to a first end of a coil of the third contactor, and a second end of the coil of the third contactor is electrically connected to the three-phase AC power supply.
4. The contactor contact adhesion protection circuit for motor forward and reverse rotation according to claim 2, characterized in that: A circuit breaker is provided between the three-phase AC power supply and the first contactor, the incoming line end of the circuit breaker is electrically connected to the three-phase AC power supply, and the outgoing line end of the circuit breaker is electrically connected to the first end of the normally open contact of the first contactor.