Motor control system
By employing pulse relays and self-locking circuits in the motor control system, the problem of abnormal motor shutdown caused by interference with PLC control signals is solved, enabling precise remote start/stop control and multiple protections for the motor, thus improving the stability and reliability of the system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-21
- Publication Date
- 2026-03-06
AI Technical Summary
PLC control signals are susceptible to interference, which can cause motor operation signal interruption and abnormal shutdown. In particular, shutdown is not allowed in critical core equipment and personnel safety systems.
The system employs pulse relays and self-locking circuits, using pulse signals to control the energization and de-energization of the relays to form a self-locking circuit, ensuring remote start-stop control and multiple protections for the motor.
It improves the stability and reliability of the motor control system, reduces the impact of remote controller failures on motor operation, achieves precise control of motor start-stop and multiple protections, and improves the continuity and stability of the production line.
Smart Images
Figure CN223978588U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of motor operation control technology, and in particular to a motor control system. Background Technology
[0002] With the development of automation systems in various industrial enterprises, the use of PLCs (Programmable Logic Controllers) to control the start and stop of field motors has become a very common technology. However, this technology suffers from the problem that PLC control signals are susceptible to interference, leading to interruptions in motor operation signals and abnormal shutdowns. This is especially true in critical and core areas of enterprises, such as the water beam cooling system of the heating furnace in a hot rolling mill, the blast furnace air supply system in an ironmaking plant, and other pump and fan systems related to equipment and personnel safety. In these cases, shutdowns due to external interference are unacceptable.
[0003] Therefore, ensuring the stability and reliability of motor operation during PLC control is a pressing technical problem that needs to be solved. Utility Model Content
[0004] In view of the above problems, this disclosure is made in order to provide a motor control system that overcomes or at least partially solves the above problems. By adopting pulse relays and self-locking circuits, the system stability and reliability are effectively improved, the impact of remote controller failures on motor operation is reduced, and precise control and multiple protections for remote motor start and stop are realized.
[0005] This disclosure provides a motor control system, including a main power supply circuit for supplying power to a controlled motor, and a control circuit for controlling the on / off state of the main power supply circuit. The main power supply circuit includes a main contactor connected in series between the controlled motor and the power supply. The control circuit includes:
[0006] The main control circuit includes a first start relay and a stop button. The coil of the first start relay is connected in series with the stop button to form a first main control circuit. The first set of normally open contacts of the first start relay is connected in series with the coil of the main contactor to form a second main control circuit. The second main control circuit is connected in parallel with the first main control circuit, and the two ends of the first main control circuit are respectively connected to the phase line and the neutral line.
[0007] The remote start / stop control module includes a third and fourth connection point of a selector switch, a second start relay, a stop relay, and a remote controller. The third connection point, the fourth connection point, and the normally open contact of the second start relay are connected in series to form a remote start / stop control circuit. The third set of normally open contacts of the first start relay and the normally closed contacts of the stop relay are connected in series to form a self-locking circuit, and the self-locking circuit is connected in parallel with the normally open contact of the second start relay. The remote start / stop control circuit is connected in series between the stop button and the coil of the first start relay.
[0008] Wherein, both the second start relay and the stop relay are pulse relays, and the coils of the second start relay and the stop relay are electrically connected to the remote controller. The remote controller is used to output corresponding pulse signals to control the coils of the second start relay or the stop relay to be energized or de-energized, so that the contacts of the second start relay or the stop relay are closed or opened, and the controlled motor is remotely started or remotely stopped.
[0009] Optionally, the second start relay is connected to the first output terminal of the remote controller, the stop relay is connected to the second output terminal of the remote controller, and the remote controller is connected to a host computer for communication.
[0010] The remote controller is configured such that when the host computer instructs the controlled motor to start, the first output terminal outputs a first pulse signal to energize the coil of the second start relay, causing the normally open contact of the second start relay to close; when the host computer instructs the controlled motor to stop, the second output terminal outputs a second pulse signal to energize the coil of the second start relay, causing the normally closed contact of the stop relay to open.
[0011] Optionally, the main power supply circuit includes an overload protection relay, the main contactor, a fuse, and a circuit breaker. The main contactor includes normally open contacts and normally closed contacts. The normally closed contacts of the overload protection relay, the normally open contacts of the main contactor, the fuse, and the circuit breaker are connected in series.
[0012] One end of the main power supply circuit is connected to the phase line of the power supply, and the other end is connected to the controlled motor;
[0013] The main contactor is configured such that when the coil of the main contactor is energized, the normally open contact of the main contactor closes and the normally closed contact opens, thus connecting the main power supply circuit; when the coil of the main contactor is de-energized, the normally open contact of the main contactor opens and the normally closed contact closes, thus disconnecting the main power supply circuit.
[0014] Optionally, the first input terminal of the remote controller is connected in series with the normally open contact of the main contactor, and the remote controller is configured to determine the operating status of the controlled motor based on the working signal input at the first input terminal;
[0015] When the normally open contact of the main contactor is open, a first working signal is input to the first input terminal, which is used to instruct the controlled motor to stop; when the normally open contact of the main contactor is closed, a second working signal is input to the first input terminal, which is used to instruct the controlled motor to start running.
[0016] Optionally, the overload protection relay includes a normally open contact and a normally closed contact, and the normally closed contact of the overload protection relay is connected in series with the first main control circuit.
[0017] The overload protection relay is configured such that when the motor experiences an overload fault, the normally closed contact of the overload protection relay opens and the normally open contact closes.
[0018] Optionally, the second input terminal of the remote controller is connected in series with the normally open contact of the overload protection relay, and the remote controller is configured to:
[0019] When the normally open contact of the overload protection relay is closed, the first output terminal outputs the second pulse signal to control the coil of the stop relay to be energized, thereby remotely stopping the controlled motor.
[0020] Optionally, the control circuit further includes a fault indication module for indicating whether the motor power supply is faulty. The fault indication module includes a fault indicator light, which is connected in series with the normally open contact of the overload protection relay to form a fault indication circuit. The fault indicator light is configured to light up when the normally open contact of the overload protection relay is closed. The two ends of the fault indication circuit are connected to the phase line and the neutral line, respectively.
[0021] Optionally, the control circuit further includes a stop indication module for indicating whether the motor has stopped. The stop indication module includes a stop indicator light, which is connected in series with the normally closed contact of the main contactor to form a stop indication circuit. The stop indicator light is configured to light up when the normally closed contact of the main contactor is opened. The two ends of the stop indication circuit are connected to the phase line and the neutral line, respectively.
[0022] Optionally, the control circuit further includes a running indicator module for indicating whether the motor has started. The running indicator module includes a running indicator light, which is connected in series with the normally open contact of the main contactor to form a running indicator circuit. The running indicator light is configured to light up when the normally open contact of the main contactor is closed. The two ends of the running indicator circuit are connected to the phase line and the neutral line, respectively.
[0023] Optionally, the control loop further includes:
[0024] The machine-side start-stop control module includes a first connection point and a second connection point of a selector switch, and a start button. The first connection point, the second connection point, and the start button are connected in series, and the second set of normally open contacts of the first start relay are connected in parallel with the start button to form a machine-side start-stop control circuit. The machine-side start-stop control circuit is connected in series between the stop button and the coil of the first start relay.
[0025] The technical solutions provided in this disclosure have at least the following technical effects or advantages:
[0026] This disclosure provides a motor control system that uses pulse relays as the second start and stop relays in a remote start / stop control module. These relays receive pulse signals from the remote controller only when needed to energize or de-energize, enabling remote start or stop of the motor. This effectively avoids the problems of control circuit susceptibility to interference and relay damage caused by prolonged relay energization, significantly improving the stability and reliability of the entire motor control system. Furthermore, the third set of normally open contacts of the first start relay and the normally closed contacts of the stop relay form a self-locking circuit. This self-locking circuit ensures that even after the second start relay is de-energized, the first start relay remains energized, thus guaranteeing the closure of the first set of normally open contacts of the first start relay in the second main control circuit, energizing the coil of the main contactor, and allowing the motor to continue running. This self-locking mechanism not only simplifies the control logic but also improves the system's fault tolerance. During remote start / stop operation of the motor, the second start relay and the remote controller no longer participate in control. Even if they fail, it will not affect the normal operation of the motor. It features uninterrupted operation even if the remote controller program crashes or the remote controller module fails. The motor's start and stop primarily rely on the state of the physical relays rather than the execution of the remote controller program, thereby reducing the impact of remote controller system failures on motor operation, improving the continuity and stability of the production line, and significantly enhancing the daily maintainability of the motor remote start / stop control module. On the other hand, by adding a motor stop relay to the control circuit, and receiving a pulse signal to disconnect the self-locking circuit when the motor needs to stop, precise control of motor shutdown is achieved. This design not only improves control flexibility but also ensures the accuracy and reliability of shutdown operations. Furthermore, to ensure equipment safety, this disclosure retains the function of the stop button, allowing it to function in emergency shutdowns at the machine site, overload shutdowns, etc., achieving multiple protections.
[0027] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are described below. Attached Figure Description
[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:
[0029] Figure 1 This is a schematic diagram of the structure of a main power supply circuit provided in an embodiment of this disclosure;
[0030] Figure 2 It is a circuit diagram of a control loop provided in related technologies;
[0031] Figure 3 This is a PLC circuit diagram provided in related technologies;
[0032] Figure 4 This is a schematic diagram of the structure of a motor control system provided in an embodiment of this disclosure;
[0033] Figure 5 This is a PLC circuit diagram provided in an embodiment of the present disclosure. Detailed Implementation
[0034] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to the accompanying drawings and specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of this disclosure, rather than limitations on the technical solutions of this disclosure. In the absence of conflict, the embodiments of this disclosure and the technical features in the embodiments can be combined with each other.
[0035] To better understand this disclosure, the following is a brief description of the specific structure of a typical main power supply circuit to which this disclosure applies:
[0036] Figure 1 This is a schematic diagram of the structure of a main power supply circuit provided in an embodiment of this disclosure, as shown below. Figure 1 As shown, the main power supply circuit is used to supply power to the controlled motor. The main power supply circuit includes an overload protection relay FR1, a main contactor KM1, a fuse FU1 and a circuit breaker QL1 connected in series. One end of the main power supply circuit is connected to the phase line of the power supply, and the other end is connected to the controlled motor M.
[0037] Figure 2 It is a circuit diagram of a control loop provided in related technologies, such as Figure 2 As shown, this control circuit is used to control the opening and closing of the contacts of the main contactor KM1 in the main power supply circuit. The control circuit includes:
[0038] The main control circuit includes a first start relay KA1 and a stop button SB1. The coil of the first start relay KA1, the normally closed contact of the overload protection relay FR1, and the stop button SB1 are connected in series to form the first main control circuit. The first set of normally open contacts of the first start relay KA1 are connected in series with the coil of the main contactor KM1 to form the second main control circuit. The second main control circuit is connected in parallel with the first main control circuit, and the two ends of the first main control circuit are connected to the phase line L and the neutral line N, respectively.
[0039] The remote start / stop control module includes the third and fourth connection points of the selector switch SA, the second start relay KA2, and the remote controller (i.e., PLC, see...) Figure 3 The third connection point, the fourth connection point, and the normally open contact of the second starting relay KA2 are connected in series to form a remote start / stop mechanism. Figure 3 This is also known as the PLC start / stop control circuit. The remote start / stop control circuit is connected in series between the stop button SB1 and the coil of the first start relay KA1.
[0040] The machine-side start-stop control module includes a first connection point and a second connection point of the selector switch SA, and a start button SB2. The first connection point, the second connection point, and the start button SB2 are connected in series, and the second set of normally open contacts of the first start relay KA1 are connected in parallel with the start button SB2 to form a machine-side start-stop control circuit. The machine-side start-stop control circuit is connected in series between the stop button SB1 and the coil of the first start relay KA1.
[0041] The coil of the second start relay KA2 is electrically connected to the remote controller PLC. The remote controller PLC is used to continuously output control signals to control the coil of the second start relay KA2 to be energized or de-energized, so that the controlled motor M can be remotely started or remotely stopped.
[0042] Figure 3 It is a PLC circuit diagram provided in related technologies, such as Figure 3 As shown, the PLC communicates with the host computer via a network cable. The PLC's first input terminal DI1 is connected to the normally open contact of the main contactor KM1 to receive the motor's running signal. The PLC's second input terminal DI2 is connected to the normally open contact of the overload protection relay FR1 to receive the motor's fault signal. The PLC's first output terminal DO1 is connected to one end of the coil of the second starting relay KA2. The other end of the coil of the second starting relay KA2 is connected to the negative terminal of the power supply, and the positive terminal of the power supply is connected to the PLC's COM terminal. When the host computer instructs the PLC to start the controlled motor, the program in the PLC runs, causing the first output terminal DO1 to output 1 and maintain it, energizing the coil of the second starting relay KA2. When the host computer instructs the PLC to stop the controlled motor, the program in the PLC runs, causing the first output terminal DO1 to output 0, de-energizing the coil of the second starting relay KA2.
[0043] The aforementioned motor control system has two start-stop methods: "machine-side start / stop" and "PLC start / stop".
[0044] (1) When the selector switch SA connects the first connection point ① and the second connection point ②, the "machine-side start / stop" function can be used. Pressing the start button SB2 energizes the first start relay KA1. The normally open contact of the first start relay KA1 will press the start button SB2, realizing the power supply self-locking function of the first start relay KA1. On the other hand, the normally open contact of the first start relay KA1 closes, energizing the coil of the main contactor KM1, thus starting the main circuit motor. When the stop button SB1 is pressed, the motor is stopped. If an overload fault occurs during motor operation (e.g.) Figure 1 The motor will also stop if the normally closed contact of the overload protection relay FR1 opens. This function requires personnel to operate at the machine and is generally used for equipment debugging; it is rarely used during normal production.
[0045] (2) When the selector switch SA connects the third connection point ③ and the fourth connection point ④, the "PLC Start / Stop" function can be used. Click the "Start" command on the host computer screen, and the PLC program will run. Figure 3 The coil of the second starting relay KA2 is energized. Figure 2 The normally open contact of the second starting relay KA2 closes, energizing the coil of the first starting relay KA1. The normally open contact of the first starting relay KA1 then closes, energizing the coil of the main contactor KM1, thus achieving remote motor start. When the "Stop" command is clicked on the host computer screen, the PLC program runs. Figure 3 The coil of the second starting relay KA2 in the middle is de-energized. Figure 2 The normally open contact of the second starting relay KA2 opens, de-energizing the coil of the first starting relay KA1, which in turn de-energizes the coil of the main contactor KM1, thus remotely stopping the motor. If, during motor operation, the PLC detects that the stop button SB1 is pressed or a motor overload fault occurs (e.g., ...), ... Figure 1 When the normally closed contact of the overload protection relay FR1 opens, the input of either the first input terminal DI1 or the second input terminal DI2 of the PLC becomes 1. The PLC then controls the output of the first output terminal DO1 to change from 1 to 0, thereby de-energizing the coil of the second starting relay KA2 and stopping the motor. This function is integrated into the PLC system and is commonly used in daily production.
[0046] However, when using the aforementioned motor control system to control the start and stop of the motor, it is necessary to [do something] during motor operation. Figure 3 The coil of the second starting relay KA2 is constantly energized. If the second starting relay KA2 loses power due to external interference or an internal fault, the control circuit will not meet requirements, causing the motor to stop. Furthermore... Figure 3 A malfunction in the PLC's DO output module can also cause the coil of the second start relay KA2 to lose power, resulting in motor shutdown. Furthermore, when... Figure 3When the hardware configuration of a PLC needs to be modified, the PLC module must be powered off and restarted. This will also cause the second start relay KA2 to lose power, resulting in the motor stopping. However, critical equipment such as water pumps and fans cannot be shut down during production and can only be modified when the company is not in operation. This leads to poor daily maintainability of the PLC.
[0047] Therefore, in order to solve the above-mentioned technical problems, the present disclosure provides a new motor control system. By adopting pulse relays and self-locking circuits, the system stability and reliability are effectively improved, the impact of remote controller failures on motor operation is reduced, and precise control and multiple protections for remote motor start and stop are realized.
[0048] The motor control system provided in this disclosure includes, as follows: Figure 1 The diagram shows the main power supply circuit for supplying power to the controlled motor, and the control circuit for controlling the on / off state of the main power supply circuit. The main power supply circuit includes a main contactor KM1 connected in series between the controlled motor M and the power supply. The control circuit is used to control the coil of the main contactor KM1 to be energized or de-energized, thereby controlling the contacts of the main contactor KM1 to close or close, thus realizing the on / off control of the main power supply circuit. Figure 4 This is a schematic diagram of the structure of a motor control system provided in an embodiment of this disclosure, as shown below. Figure 4 As shown, the control loop includes:
[0049] The main control circuit includes a first start relay KA1 and a stop button SB1. The coil of the first start relay KA1 is connected in series with the stop button SB1 to form the first main control circuit. The first set of normally open contacts of the first start relay KA1 is connected in series with the coil of the main contactor KM1 to form the second main control circuit. The second main control circuit is connected in parallel with the first main control circuit, and the two ends of the first main control circuit are connected to the phase line L and the neutral line N, respectively.
[0050] The remote start / stop control module includes the third and fourth connection points of the selector switch SA, the second start relay KA2, the stop relay KA3, and the remote controller (i.e., PLC, see...) Figure 5 The third connection point, the fourth connection point, and the normally open contact of the second starting relay KA2 are connected in series to form a remote start-stop control circuit. The third set of normally open contacts of the first starting relay KA1 is connected in series with the normally closed contact of the stop relay KA3 to form a self-locking circuit, which is connected in parallel with the normally open contact of the second starting relay KA2. The remote start-stop control circuit is connected in series between the stop button SB1 and the coil of the first starting relay KA1.
[0051] Among them, the second start relay KA2 and the stop relay KA3 are both pulse relays, and the coils of the second start relay KA2 and the stop relay KA3 are electrically connected to the remote controller PLC. The remote controller PLC is used to output corresponding pulse signals to control the coils of the second start relay KA2 or the stop relay KA3 to be energized or de-energized, so that the contacts of the second start relay KA2 or the stop relay KA3 are closed or opened, and the controlled motor M is remotely started or remotely stopped.
[0052] In the above implementation, both the first starting relay KA1 and the second starting relay KA2 are normally open relays, and the stop relay KA3 is a normally closed relay. When the coil of the first starting relay KA1 is energized, the first, second, and third normally open contacts of the first starting relay KA1 are all closed; when the coil of the first starting relay KA1 is de-energized, the first, second, and third normally open contacts of the first starting relay KA1 are all open. When the coil of the second starting relay KA2 is energized, the normally open contacts of the second starting relay KA2 are closed; when the coil of the second starting relay KA2 is de-energized, the normally open contacts of the second starting relay KA2 are open. When the coil of the stop relay KA3 is energized, the normally closed contacts of the stop relay KA3 are open; when the coil of the stop relay KA3 is de-energized, the normally closed contacts of the stop relay KA3 are closed.
[0053] It should be noted that the main contactor KM1 includes normally open contacts and normally closed contacts, such as... Figure 1 As shown, the normally closed contact of the overload protection relay FR1, the normally open contact of the main contactor KM1, the fuse FU1, and the circuit breaker QL1 are connected in series to form the main power supply circuit. One end of the main power supply circuit is connected to the phase line of the power supply, and the other end is connected to the controlled motor. The main contactor KM1 is configured such that when the coil of the main contactor KM1 is energized, the normally open contact of the main contactor KM1 closes and the normally closed contact opens, connecting the main power supply circuit; when the coil of the main contactor KM1 is de-energized, the normally open contact of the main contactor KM1 opens and the normally closed contact closes, disconnecting the main power supply circuit.
[0054] In some implementations, such as Figure 4 As shown, the control loop also includes:
[0055] The machine-side start / stop control module includes a first and second connection point of a selector switch SA, and a start button SB2. The first and second connection points and the start button SB2 are connected in series, and the second set of normally open contacts of the first start relay KA1 is connected in parallel with the start button SB2, forming a machine-side start / stop control circuit. The machine-side start / stop control circuit is connected in series between the stop button SB1 and the coil of the first start relay KA1. By setting up the machine-side start / stop control module, operators can manually start and stop the motor on-site.
[0056] In some implementations, such as Figure 4 As shown, the overload protection relay FR1 includes a normally open contact and a normally closed contact. The normally closed contact of the overload protection relay FR1 is connected in series with the first main control circuit. The overload protection relay FR1 is configured such that when an overload fault occurs in the motor, the normally closed contact of the overload protection relay FR1 opens and the normally open contact closes, thereby achieving power supply protection.
[0057] Figure 5 This is a PLC circuit diagram provided in an embodiment of the present disclosure, such as... Figure 5 As shown, the second start relay KA2 is connected to the first output terminal DO1 of the remote controller PLC, and the stop relay KA3 is connected to the second output terminal DO2 of the remote controller PLC. The remote controller PLC is connected to the host computer for communication.
[0058] The remote controller PLC is configured such that when the host computer instructs the controlled motor M to start, the first output terminal DO1 outputs a first pulse signal to energize the coil of the second start relay KA2, causing the normally open contact of the second start relay KA2 to close; when the host computer instructs the controlled motor M to stop, the second output terminal DO2 outputs a second pulse signal to energize the coil of the second start relay KA2, causing the normally closed contact of the stop relay KA3 to open.
[0059] For example, one end of the coil of the second start relay KA2 is connected to the first output terminal DO1, and the other end is connected to the negative terminal of the power supply. One end of the coil of the stop relay KA3 is connected to the second output terminal DO2, and the other end is connected to the negative terminal of the power supply. The positive terminal of the power supply is connected to the COM terminal of the remote controller PLC. When the first output terminal DO1 outputs a first pulse signal with a duration of 1 second, the coil of the second start relay KA2 is energized for 1 second, causing the normally open contact of the second start relay KA2 to close for 1 second. When the second output terminal DO2 outputs a second pulse signal with a duration of 1 second, the coil of the stop relay KA3 is energized for 1 second, causing the normally closed contact of the stop relay KA3 to open for 1 second.
[0060] Among them, the remote controller PLC is a programmable logic controller, and the staff can set the internal program of the remote controller PLC as needed to meet the above control requirements.
[0061] In some implementations, such as Figure 5 As shown, the first input terminal DI1 of the remote controller PLC is connected in series with the normally open contact of the main contactor KM1. The remote controller PLC is configured to determine the operating status of the controlled motor M based on the working signal input at the first input terminal DI1.
[0062] Specifically, when the normally open contact of the main contactor KM1 is open, the first input terminal DI1 receives a first working signal, which is used to indicate that the controlled motor M is stopped; when the normally open contact of the main contactor KM1 is closed, the first input terminal DI1 receives a second working signal, which is used to indicate that the controlled motor M is started.
[0063] In some implementations, such as Figure 5 As shown, the second input terminal DI2 of the remote controller PLC is connected in series with the normally open contact of the overload protection relay FR1. The remote controller PLC is configured as follows:
[0064] During the operation of the controlled motor M, when the normally open contact of the overload protection relay FR1 closes, the first output terminal DO1 outputs a second pulse signal, which controls the coil of the stop relay KA3 to be energized, thereby causing the controlled motor M to stop remotely.
[0065] In the above implementation, when the normally open contact of the overload protection relay FR1 closes during the operation of the controlled motor M, it indicates that the motor has an overload fault and the controlled motor M needs to be stopped in time.
[0066] In some implementations, the selection switch SA is configured as follows:
[0067] When manual control of motor start and stop is required, the connection between the first connection point ① and the second connection point ② is maintained, while the connection between the third connection point ③ and the fourth connection point ④ is disengaged; when automatic control of motor start and stop is required, the connection between the third connection point ③ and the fourth connection point ④ is maintained, while the connection between the first connection point ① and the second connection point ② is disengaged.
[0068] Combination Figure 4 and Figure 5 As can be seen, the motor control system provided in this embodiment has two start-stop methods: "machine-side start-stop" and "PLC start-stop".
[0069] (1) When the selector switch SA connects the first connection point ① and the second connection point ②, the "machine-side start / stop" function can be used. Pressing the start button SB2 energizes the first start relay KA1. The normally open contact of the first start relay KA1 will press the start button SB2, realizing the power supply self-locking function of the first start relay KA1. On the other hand, the normally open contact of the first start relay KA1 closes, energizing the coil of the main contactor KM1, thus starting the main circuit motor. When the stop button SB1 is pressed, the motor is stopped. If an overload fault occurs during motor operation (e.g.) Figure 1 The motor will also stop if the normally closed contact of the overload protection relay FR1 opens. This function requires personnel to operate at the machine and is generally used for equipment debugging; it is rarely used during normal production.
[0070] (2) When the selector switch SA is connected to the third connection point ③ and the fourth connection point ④, the "PLC Start / Stop" function is effective. At this time, clicking the "Start" command on the host computer screen will cause the program in the PLC of the remote controller to run. Figure 5 The remote controller PLC outputs a first pulse signal with a duration of 1 second at its first output terminal DO1, causing the normally open contact of the second start relay KA2 to close for 1 second. At this time... Figure 4 When the coil of the first starting relay KA1 is energized, the third set of normally open contacts of the first starting relay KA1 and the normally closed contacts of the stop relay KA3 form a new self-locking circuit. Therefore, when the normally open contact of the second starting relay KA2 closes for 1 second and then opens, the coil of the first starting relay KA1 remains energized. The first set of normally open contacts of the first starting relay KA1 energizes the main contactor KM1, and the controlled motor M starts running. During the operation of the controlled motor M, the second starting relay KA2 and the remote controller PLC no longer participate in control. Damage to the second starting relay KA2 and the remote controller PLC will not affect the normal operation of the controlled motor M. However, to improve the safety of equipment operation and prevent sudden failures, the stop button SB1 and the overload protection relay FR1 still function in the main control circuit, enabling the protection functions of emergency stop and overload stop at the machine.
[0071] When a normal shutdown is required, clicking the "Stop" command on the host computer screen will activate the remote controller PLC program. Figure 5 The second output terminal DO2 of the medium- and long-range controller PLC outputs a second pulse signal with a duration of 1 second. This energizes the coil of stop relay KA3 for 1 second, causing the normally closed contact of stop relay KA3 to open for 1 second, thus... Figure 4When the self-locking circuit in the circuit is disconnected, the coil of the first starting relay KA1 is de-energized, the first set of contacts of the first starting relay KA1 is opened, which in turn causes the coil of the main contactor KM1 in the second main control circuit to be de-energized, the normally open contact of the main contactor KM1 in the main power supply circuit to open, and the controlled motor M stops running.
[0072] In some implementations, such as Figure 4 As shown, the control circuit also includes a running indicator module for indicating whether the motor has started. The running indicator module includes a running indicator light HG1, which is connected in series with the normally open contact of the main contactor KM1 to form a running indicator circuit. The running indicator light HG1 is configured to illuminate when the normally open contact of the main contactor KM1 is closed. The two ends of the running indicator circuit are connected to the phase line L and the neutral line N, respectively. By setting up the running indicator module, operators can easily determine whether the motor has started based on the running indicator light HG1.
[0073] In some implementations, such as Figure 4 As shown, the control circuit also includes a stop indication module for indicating whether the motor has stopped. The stop indication module includes a stop indicator light HR1, which is connected in series with the normally closed contact of the main contactor KM1 to form a stop indication circuit. The stop indicator light HR1 is configured to illuminate when the normally closed contact of the main contactor KM1 opens. The two ends of the stop indication circuit are connected to the phase line L and the neutral line N, respectively. By setting up the stop indication module, operators can easily determine whether the motor has stopped based on the stop indicator light HR1.
[0074] In some implementations, such as Figure 4 As shown, the control circuit also includes a fault indication module for indicating whether the motor power supply is faulty. The fault indication module includes a fault indicator light HY1, which is connected in series with the normally open contact of the overload protection relay FR1 to form a fault indication circuit. The two ends of the fault indication circuit are connected to the phase line L and the neutral line N, respectively. The fault indicator light HY1 is configured to illuminate when the normally open contact of the overload protection relay FR1 is closed. Figure 1 As shown, the normally closed contact of the overload protection relay FR1 is connected in series in the main power supply circuit. When the motor is overloaded, the normally closed contact of the overload protection relay FR1 opens and the normally open contact closes, indicating that the motor has an overload fault. The operator can determine whether the motor has a power supply fault through the fault indicator light HY1.
[0075] The technical solutions provided in this disclosure have at least the following technical effects or advantages:
[0076] This disclosure provides a motor control system that uses pulse relays as the second start and stop relays in a remote start / stop control module. These relays receive pulse signals from the remote controller only when needed to energize or de-energize, enabling remote start or stop of the motor. This effectively avoids the problems of control circuit susceptibility to interference and relay damage caused by prolonged relay energization, significantly improving the stability and reliability of the entire motor control system. Furthermore, the third set of normally open contacts of the first start relay and the normally closed contacts of the stop relay form a self-locking circuit. This self-locking circuit ensures that even after the second start relay is de-energized, the first start relay remains energized, thus guaranteeing the closure of the first set of normally open contacts of the first start relay in the second main control circuit, energizing the coil of the main contactor, and allowing the motor to continue running. This self-locking mechanism not only simplifies the control logic but also improves the system's fault tolerance. During remote start / stop operation of the motor, the second start relay and the remote controller no longer participate in control. Even if they fail, it will not affect the normal operation of the motor. It features uninterrupted operation even if the remote controller program crashes or the remote controller module fails. The motor's start and stop primarily rely on the state of the physical relays rather than the execution of the remote controller program, thereby reducing the impact of remote controller system failures on motor operation, improving the continuity and stability of the production line, and significantly enhancing the daily maintainability of the motor remote start / stop control module. On the other hand, by adding a motor stop relay to the control circuit, and receiving a pulse signal to disconnect the self-locking circuit when the motor needs to stop, precise control of motor shutdown is achieved. This design not only improves control flexibility but also ensures the accuracy and reliability of shutdown operations. Furthermore, to ensure equipment safety, this disclosure retains the function of the stop button, allowing it to function in emergency shutdowns at the machine site, overload shutdowns, etc., achieving multiple protections.
[0077] In this disclosure, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.
[0078] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.
[0079] Furthermore, the use of terms such as "first" and "second" in this disclosure is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this disclosure.
[0080] In the description of this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0081] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.
[0082] Although preferred embodiments of the present disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.
[0083] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.
Claims
1. An electric motor control system comprising a main power supply circuit for supplying power to a motor to be controlled, and a control circuit for controlling the on-off of said main power supply circuit, said main power supply circuit comprising a main contactor connected in series between said motor to be controlled and a power source, characterized in that, The control circuit comprises: A main control circuit comprising a first start relay and a stop button, a coil of the first start relay being connected in series with the stop button to form a first main control circuit, a first group of normally open contacts of the first start relay being connected in series with a coil of the main contactor to form a second main control circuit, the second main control circuit being connected in parallel with the first main control circuit, and two ends of the first main control circuit being connected with a phase line and a zero line respectively; A remote start-stop control module comprising a third connection point and a fourth connection point of a selection switch, a second start relay, a stop relay and a remote controller, the third connection point, the fourth connection point and a normally open contact of the second start relay being connected in series to form a remote start-stop control circuit, a third group of normally open contacts of the first start relay being connected in series with a normally closed contact of the stop relay to form a self-locking holding circuit, and the self-locking holding circuit being connected in parallel with the normally open contact of the second start relay, the remote start-stop control circuit being connected in series between the stop button and the coil of the first start relay; The second start relay and the stop relay are both pulse relays, a coil of the second start relay and a coil of the stop relay are both electrically connected with the remote controller, the remote controller is configured to output corresponding pulse signals to control the coil of the second start relay or the coil of the stop relay to be powered on or powered off, so that the contacts of the second start relay or the stop relay are closed or opened, and the controlled motor is remotely started or remotely stopped.
2. The motor control system of claim 1, wherein, The second start relay is connected with a first output end of the remote controller, the stop relay is connected with a second output end of the remote controller, and the remote controller is communicatively connected with an upper computer; When the upper computer instructs to control the controlled motor to start, the first output end outputs a first pulse signal to control the coil of the second start relay to be powered on, so that the normally open contact of the second start relay is closed; when the upper computer instructs to control the controlled motor to stop, the second output end outputs a second pulse signal to control the coil of the second start relay to be powered on, so that the normally closed contact of the stop relay is opened.
3. The motor control system of claim 2, wherein, The main power supply circuit comprises an overload protection relay, the main contactor, a fuse and a circuit breaker, the main contactor comprises normally open contacts and normally closed contacts, the normally closed contact of the overload protection relay, the normally open contact of the main contactor, the fuse and the circuit breaker are connected in series; One end of the main power supply circuit is connected with a phase line of a power supply, and the other end is connected with the controlled motor; When the coil of the main contactor is powered on, the normally open contact of the main contactor is closed, the normally closed contact is opened, and the main power supply circuit is connected; when the coil of the main contactor is powered off, the normally open contact of the main contactor is opened, the normally closed contact is closed, and the main power supply circuit is disconnected.
4. The motor control system of claim 3, wherein, The first input end of the remote controller is connected in series with the normally open contact of the main contactor, and the remote controller is configured to determine the running state of the controlled motor based on a working signal input by the first input end. When the normally open contact of the main contactor is open, the first input end inputs a first working signal, and the first working signal is used to instruct the controlled motor to stop; when the normally open contact of the main contactor is closed, the first input end inputs a second working signal, and the second working signal is used to instruct the controlled motor to start running.
5. The motor control system of claim 3, wherein, The overload protection relay comprises a normally open contact and a normally closed contact, and the normally closed contact of the overload protection relay is connected in series with the first main control circuit. When the motor generates an overload fault, the normally closed contact of the overload protection relay is open, and the normally open contact is closed.
6. The motor control system of claim 5, wherein, The second input end of the remote controller is connected in series with the normally open contact of the overload protection relay, and the remote controller is configured to: When the normally open contact of the overload protection relay is closed, the first output end outputs the second pulse signal to control the coil of the stop relay to be powered, so that the controlled motor is remotely stopped.
7. The motor control system of claim 5, wherein, The control circuit further comprises a fault indication module for indicating whether the power supply of the motor is faulty, the fault indication module comprises a fault indication lamp, the fault indication lamp is connected in series with the normally open contact of the overload protection relay to form a fault indication circuit, and the fault indication lamp is configured to emit light when the normally open contact of the overload protection relay is closed. The two ends of the fault indication circuit are connected with the phase line and the zero line respectively.
8. The motor control system of claim 3, wherein, The control circuit further comprises a stop indication module for indicating whether the motor is stopped, the stop indication module comprises a stop indication lamp, the stop indication lamp is connected in series with the normally closed contact of the main contactor to form a stop indication circuit, and the stop indication lamp is configured to emit light when the normally closed contact of the main contactor is open. The two ends of the stop indication circuit are connected with the phase line and the zero line respectively.
9. The motor control system of claim 3, wherein, The control circuit further comprises a running indication module for indicating whether the motor is started, the running indication module comprises a running indication lamp, the running indication lamp is connected in series with the normally open contact of the main contactor to form a running indication circuit, and the running indication lamp is configured to emit light when the normally open contact of the main contactor is closed. The two ends of the running indication circuit are connected with the phase line and the zero line respectively.
10. The motor control system of claim 1, wherein, The control circuit further comprises: The machine-side start-stop control module comprises a first connection point and a second connection point of a selection switch and a start button, the first connection point, the second connection point and the start button are connected in series, and the second group of normally open contacts of the first start relay are connected in parallel with the start button to form a machine-side start-stop control circuit; the machine-side start-stop control circuit is connected in series between the stop button and the coil of the first start relay.