Motor frequency conversion control circuit

Abstract

The utility model relates to a frequency conversion control circuit of a motor. A frequency converter is arranged in a main circuit; the frequency converter is electrically connected with a motor; connecting the frequency converter to a remote control circuit; a remote control point location is arranged in the remote control circuit; on-off of point positions is remotely controlled, and the motor is remotely and automatically controlled through a control frequency converter of a remote control circuit; input and output control is used, starting and stopping control can be achieved in a remote control mode, and the problems that in an existing motor frequency conversion control circuit, starting and stopping are generally controlled through a local control mode or frequency conversion control is conducted through remote control in a communication mode, but remote control point position control is rarely used are solved. In a place where communication interference is severe, the technical problems that starting and stopping are controlled in a local control mode, the temperature is too high, approaching is not easy, remote control is prone to electromagnetic interference, and control fails are solved.

Description

Technical Field

[0001] The embodiments of the utility model relate to a motor control circuit, and in particular to a motor frequency conversion control circuit. Background Art

[0002] In existing motor frequency conversion control circuits, local control methods are generally used to control start and stop, or remote control uses communication methods for frequency conversion control. Remote control point control is rarely used. However, in places where communication interference is relatively strong, such as liquid crystal polymer melting occasions, in the case of commonly used high-power electromagnetic induction furnaces, when local control methods are used to control start and stop, the temperature is too high and it is difficult to access. Remote control is easily affected by electromagnetic interference, resulting in control failure. Utility Model Content

[0003] The purpose of the embodiment of the present utility model is to provide a remote control point control method, which can realize start and stop control using a remote control method.

[0004] In order to achieve the above-mentioned purpose, the embodiment of the present invention designs a motor frequency conversion control circuit, comprising:

[0005] Main circuit;

[0006] A frequency converter is provided in the main circuit;

[0007] a motor, electrically connected to the frequency converter;

[0008] a remote control circuit, connecting the frequency converter to the remote control circuit;

[0009] A remote control point is set in the remote control circuit; the remote control point is turned on and off, and the inverter is controlled by the remote control circuit to remotely and automatically control the motor.

[0010] Furthermore, in the motor frequency conversion control circuit of the present utility model, the main circuit further includes:

[0011] A circuit breaker is connected to the line-in terminal of the frequency converter and the line-out terminal of the circuit breaker;

[0012] A main power supply, connected to the line inlet terminal of the circuit breaker;

[0013] The output reactor is connected to the output terminal of the frequency converter; and the motor is connected to the output terminal of the output reactor.

[0014] Furthermore, in the motor frequency conversion control circuit of the present invention, the model of the frequency converter is ACS880-01-D-3.

[0015] Furthermore, in the motor frequency conversion control circuit of the present invention, the reactor is a LOCH series reactor.

[0016] Furthermore, in the motor frequency conversion control circuit of the present utility model, the remote control circuit further includes:

[0017] Control power supply;

[0018] Miniature circuit breaker, connecting the control power supply to the line inlet terminal of the miniature circuit breaker;

[0019] A transfer switch, wherein the outlet terminal of the miniature circuit breaker is connected to the fifth terminal of the transfer switch;

[0020] A stop button, wherein the outlet terminal of the miniature circuit breaker is connected to the inlet terminal of the stop button; the outlet terminal of the stop button is connected to the first terminal of the transfer switch and the third terminal of the transfer switch;

[0021] The output terminals of the miniature circuit breaker are respectively connected to the first output contact of the frequency converter, the first contact of the fifth intermediate relay, the second output contact of the frequency converter, the third output contact of the frequency converter, and the input terminals of the first contact of the sixth intermediate relay;

[0022] The sixth terminal of the transfer switch is connected to the input terminal of the third intermediate relay coil; the output terminal of the third intermediate relay coil is connected to the neutral line;

[0023] The second end of the transfer switch is connected to the input end of the start button and the input end of the first contact of the fourth intermediate relay respectively; the output end of the start button is connected to the output end of the first contact of the fourth intermediate relay, and then connected to the input end of the first contact of the second intermediate relay;

[0024] The second end of the transfer switch is connected to the incoming end of the first contact of the first intermediate relay and the second contact of the fourth intermediate relay respectively; the outgoing end of the first contact of the first intermediate relay and the second contact of the fourth intermediate relay are connected, and then connected to the incoming end of the first contact of the second intermediate relay;

[0025] The outgoing terminal of the first contact of the second intermediate relay is connected to the incoming terminal of the second contact of the sixth intermediate relay; the outgoing terminal of the second contact of the sixth intermediate relay is connected to the incoming terminal of the fourth intermediate relay coil; the outgoing terminal of the fourth intermediate relay coil is connected to the neutral line;

[0026] The outgoing terminal of the first output contact of the frequency converter is connected to the incoming terminal of the fifth intermediate relay coil; the outgoing terminal of the fifth intermediate relay coil is connected to the neutral line;

[0027] The outgoing terminal of the first contact of the fifth intermediate relay is connected to the incoming terminal of the operation indicator light; the outgoing terminal of the operation indicator light is connected to the neutral line;

[0028] The outgoing line end of the second output contact of the frequency converter is connected to the incoming line end of the frequency converter ready indicator light; the outgoing line end of the frequency converter ready indicator light is connected to the neutral line;

[0029] The outgoing terminal of the third output contact of the frequency converter is connected to the incoming terminal of the sixth intermediate relay coil; the outgoing terminal of the sixth intermediate relay coil is connected to the neutral line;

[0030] The outgoing terminal of the first contact of the sixth intermediate relay is connected to the incoming terminal of the fault indicator light; and the outgoing terminal of the fault indicator light is connected to the neutral line.

[0031] Furthermore, in the motor frequency conversion control circuit of the present invention, the XD24.4 port of the frequency converter is connected to the third contact of the fourth intermediate relay, the first contact of the third intermediate relay, and the incoming line terminal of the thermal resistor in the motor body respectively;

[0032] The output terminal of the third contact of the fourth intermediate relay is connected to the XD 1.1 port of the frequency converter;

[0033] The outlet end of the first contact of the third intermediate relay is connected to the XD 1.5 port of the frequency converter;

[0034] The outlet end of the thermal resistor in the motor body is connected to the XD 1.6 port of the inverter;

[0035] Setting a Profibus DP port on the frequency converter to communicate with the DCS communication interface;

[0036] Set the first analog speed control input port on the XAI.4 port and XAI.5 port of the inverter;

[0037] Connect the first analog speed control output port to the XAO.1 port and XAO.2 port of the frequency converter respectively.

[0038] Furthermore, in the motor frequency conversion control circuit of the present invention, a controller output endpoint is provided on the remote control circuit to control the start and stop of the frequency converter.

[0039] Furthermore, in the motor frequency conversion control circuit of the present invention, the remote control point is a DCS output point.

[0040] Furthermore, in the motor frequency conversion control circuit of the present utility model, the DCS output point further includes:

[0041] A first DCS output point, one end of a first intermediate relay coil is connected to the first DCS output point, and the other end of the first intermediate relay coil is connected to a 24V power supply;

[0042] The second DCS output point is connected to the second DCS output point at one end of the second intermediate relay coil, and the other end of the second intermediate relay coil is connected to a 24V power supply.

[0043] Furthermore, in the motor frequency conversion control circuit of the present invention, the first DCS output point controls the first intermediate relay coil to be energized and closed to start the inverter; the second DCS output point controls the second intermediate relay coil to be energized and closed to stop the inverter.

[0044] Compared with the prior art, the implementation method of the present invention adopts the following methods: a frequency converter is set in the main circuit; a motor is electrically connected to the frequency converter; the frequency converter is connected to a remote control circuit; a remote control point is set in the remote control circuit; the remote control point is turned on and off, and the motor is remotely and automatically controlled by controlling the frequency converter of the remote control circuit; the present invention uses input and output control to realize start and stop control by remote control, which solves the technical problem that in the existing motor frequency conversion control circuit, local control is generally used to control start and stop, or remote control uses communication to perform frequency conversion control, and remote control point control is rarely used. However, in places where communication interference is relatively strong, the temperature is too high and it is difficult to access the local control method for start and stop control, and the remote control is easily affected by electromagnetic interference, resulting in control failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the main circuit of the utility model;

[0046] Figure 2 This is a schematic diagram of the control circuit of the utility model;

[0047] Figure 3 This is a schematic diagram of the remote control points of the utility model;

[0048] Figure 4 This is a schematic diagram of the frequency converter control of the present utility model. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in various embodiments of the present invention to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the claims of this application can be achieved.

[0050] The first embodiment of the present invention relates to a motor frequency conversion control circuit, such as Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, including:

[0051] The main circuit in this embodiment is the motor frequency conversion control circuit in this embodiment to perform main circuit control;

[0052] Set up a frequency converter VFD in the main circuit;

[0053] The motor M3 is electrically connected to the frequency converter VFD; the frequency converter VFD controls the speed of the motor M3 and performs speed regulation;

[0054] Connect the frequency converter VFD to the remote control circuit; the remote control circuit controls the frequency converter VFD to switch on and off and adjust the speed;

[0055] A remote control point is set in the remote control circuit; the on and off of the remote control point is used to remotely and automatically control the motor M3~ through the control frequency converter VFD of the remote control circuit. The remote control point realizes remote control of the frequency converter VFD; this embodiment uses remote control point control to realize start and stop control using a remote control method, which solves the technical problem that in existing motor frequency conversion control circuits, local control methods are generally used for control start and stop, or remote control uses communication methods for frequency conversion control, and remote control point control is rarely used. However, in areas with strong communication interference, the use of local control methods for control start and stop is too high, difficult to access, and remote control is easily affected by electromagnetic interference, resulting in control failure.

[0056] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the main circuit also includes:

[0057] The line input terminal of the frequency converter VFD is connected to the line output terminal of the circuit breaker QF; the circuit breaker QF is used to open and close the main circuit;

[0058] The main power supplies L1, L2, L3, and N are connected to the line input terminal of the circuit breaker QF. The main power supplies L1, L2, L3, and N provide power for the motor frequency conversion control circuit in this embodiment.

[0059] Connect the input terminal of the output reactor L to the output terminal of the inverter VFD; connect the motor M3 to the output terminal of the output reactor L. The output reactor L is used to suppress the starting current during the startup process of the inverter VFD.

[0060] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown in the figure, the model of the frequency converter VFD is ACS880-01-D-3.

[0061] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the reactor is a LOCH series reactor.

[0062] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the remote control circuit also includes:

[0063] Control power supplies UPS+ and UPS- of the remote control circuit in the motor frequency conversion control circuit of this embodiment;

[0064] Connect the control power supplies UPS+ and UPS- to the incoming line terminals of the miniature circuit breaker QF1; the miniature circuit breaker QF1 is used to switch the control power supplies UPS+ and UPS- on and off.

[0065] The outgoing terminal of miniature circuit breaker QF1 is connected to the fifth terminal of transfer switch 1SA; transfer switch 1SA is used to switch between manual mode and remote control mode;

[0066] The output terminal of the miniature circuit breaker QF1 is connected to the input terminal of the stop button 1SS; the output terminal of the stop button 1SS is connected to the first terminal and the third terminal of the transfer switch 1SA; the stop button 1SS is used to stop the frequency converter VFD;

[0067] The outgoing terminals of the miniature circuit breaker QF1 are respectively connected to the incoming terminals of the first output contact VFD-1 of the inverter, the first contact KA5-1 of the fifth intermediate relay, the second output contact VFD-2 of the inverter, the third output contact VFD-3 of the inverter, and the first contact KA6-1 of the sixth intermediate relay;

[0068] The sixth terminal of the transfer switch 1SA is connected to the input terminal of the third intermediate relay coil KA3; the output terminal of the third intermediate relay coil KA3 is connected to the neutral line N; the above circuit realizes automatic control bit expansion.

[0069] The second terminal of the transfer switch 1SA is connected to the input terminal of the start button 1SF and the input terminal of the first contact KA4-1 of the fourth intermediate relay respectively; the output terminal of the start button 1SF is connected to the output terminal of the first contact KA4-1 of the fourth intermediate relay, and then connected to the input terminal of the first contact KA2-1 of the second intermediate relay;

[0070] The second terminal of the transfer switch 1SA is connected to the incoming line terminals of the first contact KA1-1 of the first intermediate relay and the second contact KA4-2 of the fourth intermediate relay respectively; the outgoing line terminals of the first contact KA1-1 of the first intermediate relay and the second contact KA4-2 of the fourth intermediate relay are connected, and then connected to the incoming line terminal of the first contact KA2-1 of the second intermediate relay;

[0071] The output terminal of the first contact KA2-1 of the second intermediate relay is connected to the input terminal of the second contact KA6-2 of the sixth intermediate relay; the output terminal of the second contact KA6-2 of the sixth intermediate relay is connected to the input terminal of the fourth intermediate relay coil; the output terminal of the fourth intermediate relay coil is connected to the neutral line N; the above circuit realizes the frequency converter VFD controlling the motor M3~, and starts and stops the motor M3~ in manual mode and remote mode.

[0072] The output terminal of the first output contact VFD-1 of the inverter is connected to the input terminal of the fifth intermediate relay coil KA5; the output terminal of the fifth intermediate relay coil KA5 is connected to the neutral line N; the above circuit realizes the operation extension output.

[0073] The outgoing terminal of the first contact KA5-1 of the fifth intermediate relay is connected to the incoming terminal of the operation indicator light HR; the outgoing terminal of the operation indicator light HR is connected to the neutral line N; the above circuit realizes the lighting of the operation indicator light HR.

[0074] The outgoing terminal of the second output contact VFD-2 of the inverter is connected to the incoming terminal of the inverter ready indicator HG; the outgoing terminal of the inverter ready indicator HG is connected to the neutral line N; the above circuit is used to light up the inverter ready indicator HG.

[0075] The output terminal of the third output contact VFD-3 of the inverter is connected to the input terminal of the sixth intermediate relay coil KA6; the output terminal of the sixth intermediate relay coil KA6 is connected to the neutral line N; the above circuit is used to output the fault expansion signal.

[0076] The outgoing line of the first contact KA6-1 of the sixth intermediate relay is connected to the incoming line of the fault indicator light HY; the outgoing line of the fault indicator light HY is connected to the neutral line N. The above circuit is used to light up the fault indicator light (HY)

[0077] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the XD24.4 port of the frequency converter VFD is connected to the third contact KA4-3 of the fourth intermediate relay, the first contact KA3-1 of the third intermediate relay, and the incoming line terminal of the thermal resistor PTC in the motor body;

[0078] The output terminal of the third contact KA4-3 of the fourth intermediate relay is connected to the XDI.1 port of the frequency converter VFD; the operating status of the control circuit is input to the XDI.1 port of the frequency converter VFD, thereby realizing the input confirmation of the operating status.

[0079] The output terminal of the first contact KA3-1 of the third intermediate relay is connected to the XDI.5 port of the frequency converter VFD; the automatic state of the control circuit is input to the XDI.5 port of the frequency converter VFD, thereby realizing automatic state input confirmation.

[0080] The output terminal of the thermal resistor PTC in the motor body is connected to the XDI.6 port of the inverter VFD; the thermal resistor PTC is used to protect the motor M3~ by detecting the heating condition of the motor.

[0081] Set up the Profibus DP port on the VFD to connect with the DCS communication interface for remote communication;

[0082] The first analog speed control input port is set on the XAI.4 port and XAI.5 port of the frequency converter VFD to be used for connecting to the analog speed regulator.

[0083] The first analog speed control output port is connected to the XAO.1 port and XAO.2 of the frequency converter VFD respectively for outputting analog speed control.

[0084] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the controller output endpoint is set on the remote control circuit to control the start and stop of the inverter VFD.

[0085] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the remote control point is the DCS output point.

[0086] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, DCS output points also include:

[0087] One end of the first intermediate relay coil KA1 is connected to the first DCS output point DCS-1, and the other end of the first intermediate relay coil KA1 is connected to a 24V power supply; the first DCS output point DCS-1 is used to start the remote control point output.

[0088] One end of the second intermediate relay coil KA2 is connected to the second DCS output point DCS-2, and the other end of the second intermediate relay coil KA2 is connected to a 24V power supply. The second DCS output point DCS-2 is used to stop the remote control point output.

[0089] In order to achieve the above technical problems, the motor frequency conversion control circuit in this embodiment is as follows: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the first DCS output point DCS-1 controls the first intermediate relay coil KA1 to be energized and closed to start the frequency converter VFD; the second DCS output point DCS-2 controls the second intermediate relay coil KA2 to be energized and closed to stop the frequency converter VFD.

[0090] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A motor frequency conversion control circuit, characterized in that: include: Main circuit; a frequency converter (VFD), wherein the frequency converter (VFD) is provided in the main circuit; a motor (M3-), electrically connected to the frequency converter (VFD); a remote control circuit, connecting the variable frequency drive (VFD) to the remote control circuit; A remote control point is set in the remote control circuit; the remote control point is turned on and off, and the frequency converter (VFD) is controlled by the remote control circuit to remotely and automatically control the motor (M3~).

2. The motor frequency conversion control circuit according to claim 1, characterized in that: The main circuit further includes: a circuit breaker (QF), connected to the output terminal of the circuit breaker (QF) at the input terminal of the frequency converter (VFD); The main power supply (L1, L2, L3, N) is connected to the incoming terminal of the circuit breaker (QF). An output reactor (L) is connected to the input terminal of the output reactor (L) at the output terminal of the frequency converter (VFD); and the motor (M3) is connected to the output terminal of the output reactor (L).

3. The motor frequency conversion control circuit according to claim 1, characterized in that: The model of the frequency converter (VFD) is ACS880-01-D-3.

4. The motor frequency conversion control circuit according to claim 2, characterized in that: The reactor is a LOCH series reactor.

5. The motor frequency conversion control circuit according to claim 1, characterized in that: The remote control circuit further includes: Control power supply (UPS+, UPS-); Miniature circuit breaker (QF1), connecting the control power supply (UPS+, UPS-) to the incoming line terminal of the miniature circuit breaker (QF1); A transfer switch (1SA), wherein the outlet terminal of the miniature circuit breaker (QF1) is connected to the fifth terminal of the transfer switch (1SA); A stop button (1SS), the outlet end of the miniature circuit breaker (QF1) is connected to the inlet end of the stop button (1SS); the outlet end of the stop button (1SS) is connected to the first terminal of the transfer switch (1SA) and the third terminal of the transfer switch (1SA); The output terminal of the miniature circuit breaker (QF1) is respectively connected to the input terminal of the first output contact of the frequency converter (VFD-1), the first contact of the fifth intermediate relay (KA5-1), the second output contact of the frequency converter (VFD-2), the third output contact of the frequency converter (VFD-3), and the first contact of the sixth intermediate relay (KA6-1); The sixth terminal of the transfer switch (1SA) is connected to the incoming terminal of the third intermediate relay coil (KA3); the outgoing terminal of the third intermediate relay coil (KA3) is connected to the neutral line (N); The second end of the transfer switch (1SA) is respectively connected to the incoming end of the start button (1SF) and the incoming end of the first contact (KA4-1) of the fourth intermediate relay; the outgoing end of the start button (1SF) is connected to the outgoing end of the first contact (KA4-1) of the fourth intermediate relay, and then connected to the incoming end of the first contact (KA2-1) of the second intermediate relay; The second end of the transfer switch (1SA) is connected to the incoming end of the first contact (KA1-1) of the first intermediate relay and the second contact (KA4-2) of the fourth intermediate relay respectively; the outgoing end of the first contact (KA1-1) of the first intermediate relay and the second contact (KA4-2) of the fourth intermediate relay are connected and then connected to the incoming end of the first contact (KA2-1) of the second intermediate relay; The outgoing line terminal of the first contact point (KA2-1) of the second intermediate relay is connected to the incoming line terminal of the second contact point (KA6-2) of the sixth intermediate relay; the outgoing line terminal of the second contact point (KA6-2) of the sixth intermediate relay is connected to the incoming line terminal of the fourth intermediate relay coil; the outgoing line terminal of the fourth intermediate relay coil is connected to the neutral line (N); The output terminal of the first output contact of the frequency converter (VFD-1) is connected to the input terminal of the fifth intermediate relay coil (KA5); the output terminal of the fifth intermediate relay coil (KA5) is connected to the neutral line (N); The outgoing line terminal of the first contact point (KA5-1) of the fifth intermediate relay is connected to the incoming line terminal of the operation indicator light (HR); the outgoing line terminal of the operation indicator light (HR) is connected to the neutral line (N); The outgoing terminal of the second output contact of the inverter (VFD-2) is connected to the incoming terminal of the inverter ready indicator light (HG); the outgoing terminal of the inverter ready indicator light (HG) is connected to the neutral line (N); The output terminal of the third output contact (VFD-3) of the frequency converter is connected to the input terminal of the sixth intermediate relay coil (KA6); the output terminal of the sixth intermediate relay coil (KA6) is connected to the neutral line (N); The outgoing line end of the first contact point (KA6-1) of the sixth intermediate relay is connected to the incoming line end of the fault indicator light (HY); the outgoing line end of the fault indicator light (HY) is connected to the neutral line (N).

6. The motor frequency conversion control circuit according to claim 1, characterized in that: The XD24.4 port of the frequency converter (VFD) is connected to the third contact of the fourth intermediate relay (KA4-3), the first contact of the third intermediate relay (KA3-1), and the incoming line terminal of the thermal resistor (PTC) in the motor body; The outgoing terminal of the third contact (KA4-3) of the fourth intermediate relay is connected to the XDI.1 port of the frequency converter (VFD); The outlet end of the first contact (KA3-1) of the third intermediate relay is connected to the XDI.5 port of the frequency converter (VFD); The outgoing terminal of the thermal resistor (PTC) in the motor body is connected to the XDI.6 port of the frequency converter (VFD); Setting a Profibus DP port on the frequency converter (VFD) to communicate with the DCS communication interface; A first analog speed control input port is set on the XAI.4 port and the XAI.5 port of the frequency converter (VFD); The first analog speed control output port is connected to the XAO.1 port and XAO.2 port of the frequency converter (VFD) respectively.

7. The motor frequency conversion control circuit according to claim 5, characterized in that: A controller output terminal is set on the remote control circuit to control the start and stop of the variable frequency drive (VFD).

8. The motor frequency conversion control circuit according to claim 1, characterized in that: The remote control point is a DCS output point.

9. The motor frequency conversion control circuit according to claim 8, characterized in that: The DCS output point also includes: A first DCS output point (DCS-1), one end of a first intermediate relay coil (KA1) is connected to the first DCS output point (DCS-1), and the other end of the first intermediate relay coil (KA1) is connected to a 24V power supply; The second DCS output point (DCS-2) is connected to the second DCS output point (DCS-2) at one end of the second intermediate relay coil (KA2), and the other end of the second intermediate relay coil (KA2) is connected to a 24V power supply.

10. The motor frequency conversion control circuit according to claim 9, characterized in that: The first DCS output point (DCS-1) controls the first intermediate relay coil (KA1) to be energized and closed, thereby starting the frequency converter (VFD); the second DCS output point (DCS-2) controls the second intermediate relay coil (KA2) to be energized and closed, thereby stopping the frequency converter (VFD).

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