CN218997961U - Locked rotor control circuit - Google Patents

Abstract

The utility model relates to a locked rotor control circuit, which comprises a detection element, wherein the detection element is used for acquiring signals of a motor; the DCS control unit is connected with the detection element and is used for receiving the signals acquired by the detection element and judging whether the motor is blocked or not according to the received signals acquired by the detection element; and the DCS control unit is used for controlling the motor forward and backward rotation control circuit, so that the motor is controlled by the motor forward and backward rotation control circuit to switch the running state of the motor during locked rotation. According to the utility model, through the detection element and the DCS control system, the motor can be controlled to switch the motion state in time when the motor is blocked, so that the problem of blocking of the motor is solved, and blocked materials are dredged.

Description

Locked rotor control circuit

Technical Field

The utility model belongs to the technical field of active coke desulfurization and denitrification devices, and particularly relates to a locked rotor control circuit.

Background

In the active coke desulfurization and denitrification device, the materials in the reactor and the regenerator are frequently blocked in the blanking process, the volumes of the reactor and the regenerator are overlarge, the materials are more stored, a large amount of manpower and material resources are required if the materials are blocked by adopting a conventional method for disassembling and dredging the materials in a power failure, and the longer power failure time is required and can influence the normal operation of the active coke desulfurization and denitrification device.

Disclosure of Invention

In order to solve all or part of the problems, the utility model aims to provide a locked rotor control circuit, which detects whether locked rotor occurs or not through a detection element, so that a DCS control system can timely control a motor to switch operation states during locked rotor, and thus blocked materials can be dredged.

According to an aspect of the present utility model, there is provided a stall control circuit comprising:

the detection element is used for acquiring signals of the motor;

the DCS control unit is connected with the detection element and is used for receiving the signals acquired by the detection element and judging whether the motor is locked or not according to the received signals acquired by the detection element;

the motor forward and backward rotation circuit comprises a motor forward and backward rotation working circuit and a motor forward and backward rotation control circuit, the DCS control unit is connected with the motor forward and backward rotation control circuit and used for controlling the motor forward and backward rotation control circuit, and the DCS control unit is convenient for switching the motor running state when the motor is controlled by the motor forward and backward rotation control circuit to stop rotating.

Further, the motor forward and reverse rotation control circuit comprises a forward rotation control circuit, a reverse rotation control circuit and an emergency stop control circuit which are arranged between the control line L1 and the zero line N;

the DCS forward rotation control circuit is provided with a DCS forward rotation normally-open contact, an SB1 forward rotation button and a normally-open contact of an alternating current contactor KM1, both ends of the DCS forward rotation normally-open contact and both ends of the normally-open contact of the alternating current contactor KM1 are connected in parallel with both ends of the SB1 forward rotation button, one end of the SB1 forward rotation button is connected with a control line L1, and a normally-closed contact of an alternating current contactor KM2, a coil of the alternating current contactor KM1 and a normally-closed contact of a current relay KA1 are sequentially connected between the other end of the SB1 forward rotation button and a zero line N;

the reversing control circuit is provided with a DCS reversing normally open contact, an SB2 reversing button and a normally open contact of an alternating current contactor KM2, both ends of the DCS reversing normally open contact and both ends of the normally open contact of the alternating current contactor KM2 are connected in parallel with both ends of the SB2 reversing button, one end of the SB2 reversing button is connected with a control line L1, the other end of the SB2 reversing button is connected with one end of a normally closed contact of the alternating current contactor KM1, the other end of the normally closed contact of the alternating current contactor KM1 is connected with one end of a coil of the alternating current contactor KM2, and one end of the coil of the alternating current contactor KM1 is connected between the coil of the alternating current contactor KM1 and the normally closed contact of the current relay KA 1;

the emergency stop control circuit is provided with a DCS (distributed control system) stop button and an SB3 emergency stop button, the DCS stop button is connected with the SB3 emergency stop button in parallel, one end of the SB3 emergency stop button is connected with the control line L1, the other end of the SB3 emergency stop button is connected with one end of a coil of the current relay KA1, and the other end of the coil of the current relay KA1 is connected to the zero line N;

the DCS forward rotation normally open contact, the DCS reverse rotation normally open contact and the DCS stop button are all connected with the DCS control unit;

the motor forward and backward rotation working circuit is provided with a normally open contact of an alternating current contactor KM1 and a normally open contact of an alternating current contactor KM2, when the normally open contact of the alternating current contactor KM1 is closed, the motor rotates forward, and when the normally open contact of the alternating current contactor KM2 is closed, the motor rotates backward.

Further, the detection element is a temperature detection resistor, and two ends of the temperature detection resistor are respectively connected with an 11 output end and a 14 output end of the protection relay;

the power A1 end of the protection relay is connected with the control line L1, and the power A2 end of the protection relay is connected with the zero line N.

Further, the intelligent power supply further comprises an alternating current relay KA2, wherein the T1 end of the protective relay is connected with the control line L1, the T2 end of the protective relay is connected with one end of a coil of the current relay KA2, and the other end of the coil of the current relay KA2 is connected with the zero line N;

the normally closed contact of the current relay KA2 is arranged between the normally closed contact of the current relay KA1 and the neutral line N.

Further, the detection element is a current transformer, a primary side winding of the current transformer is connected in series to the motor forward and reverse rotation operating circuit, and an ammeter is connected between two ends of a secondary side winding of the current transformer.

Further, two ends of the ammeter are respectively connected with the control line L1 and the zero line N, the control line L1 is connected with one end of the secondary side winding of the current transformer, and the zero line N is connected with the other end of the secondary side winding of the current transformer.

Further, the control line L1 is connected with one end of a normally open contact of the ac contactor KM1, the other end of the normally open contact of the ac contactor KM1 is connected with one end of a forward rotation indicator lamp, and the other end of the forward rotation indicator lamp is connected with the zero line N;

the control line L1 is connected with one end of a normally open contact of the alternating current contactor KM2, the other end of the normally open contact of the alternating current contactor KM2 is connected with one end of a reverse indicator lamp, and the other end of the reverse indicator lamp is connected with the zero line N;

the control line L1 is connected with one end of a normally closed contact of an alternating current contactor KM1, the other end of the normally closed contact of the alternating current contactor KM1 is connected with one end of a normally closed contact of an alternating current contactor KM2, the other end of the normally closed contact of the alternating current contactor KM2 is connected with one end of a scram indicator lamp, and the other end of the scram indicator lamp is connected with a zero line N.

Further, a breaker QF is arranged on the motor forward and backward rotation working circuit, a thermal element of a thermal relay FR is arranged on the motor forward and backward rotation working circuit, and a normally closed contact of the thermal relay FR is arranged between a connection point of the reverse rotation control circuit and the forward rotation control circuit and a normally closed contact of the current relay KA 1.

Further, the number of normally open contacts of the ac contactor KM1 and the number of normally open contacts of the ac contactor KM2 on the motor forward and backward rotation operation circuit are 3, wherein:

two ends of a normally open contact of a first alternating current contactor KM1 are respectively connected between a power line A and a U-phase line of the motor, two ends of a normally open contact of the second alternating current contactor KM1 are respectively connected between a power line B and a V-phase line of the motor, and two ends of a normally open contact of a third alternating current contactor KM1 are respectively connected between a power line C and a W-phase line of the motor;

the two ends of the normally open contact of the first alternating current contactor KM2 are respectively connected between the power line A and the W phase line of the motor, the two ends of the normally open contact of the second alternating current contactor KM2 are respectively connected between the power line B and the V phase line of the motor, and the two ends of the normally open contact of the third alternating current contactor KM2 are respectively connected between the power line C and the U phase line of the motor.

Further, a fuse FU is provided on the control line L1, and the fuse is located upstream of the forward rotation control circuit, the reverse rotation control circuit, and the scram control circuit.

According to the technical scheme, the locked rotor control circuit provided by the utility model has the following beneficial effects:

according to the utility model, whether the motor is blocked or not can be detected through the detection element, so that the motor can be controlled to switch the motion state in time when the motor is blocked through the DCS control system, the problem of the motor blocking is solved, and blocked materials are dredged; compared with the shutdown processing in the prior art, the utility model realizes the automatic processing of the locked-rotor and shortens the dredging time after the locked-rotor.

Drawings

FIG. 1 is a schematic diagram of the reactor and regenerator blanking portions;

FIG. 2 is a schematic circuit diagram of a motor forward and reverse rotation control circuit according to an embodiment of the present utility model;

FIG. 3 is a schematic circuit diagram of a forward and reverse rotation operating circuit of the motor corresponding to the schematic diagram of FIG. 2;

FIG. 4 is a schematic circuit diagram of a motor forward and reverse rotation control circuit according to another embodiment of the present utility model;

FIG. 5 is a schematic circuit diagram of a forward and reverse rotation operating circuit of the motor corresponding to the schematic diagram of FIG. 4;

the reference numerals in the drawings are:

the automatic feeding device comprises a motor 1, a speed change mechanism 2, a cover body 3 and a feeding pipe 4;

the protection relay 01, the temperature detection resistor 02, the DCS forward rotation normally open contact 03, the DCS reverse rotation normally open contact 04, the DCS stop button 05 and the current transformer 06.

Detailed Description

For a better understanding of the objects, structures and functions of the present utility model, a locked rotor control circuit according to the present utility model will be described in further detail with reference to the accompanying drawings.

The technical scheme of the utility model is applied to a structure that the blanking is driven by the rotation of a motor, for example, the structure is applied to the blanking process of a reactor and a regenerator of an active coke desulfurization and denitrification device. As shown in fig. 1, the discharging part of the reactor and the regenerator specifically comprises two sections of discharging pipes 4, a cover body 3 is arranged between the two sections of discharging pipes 4, a driving motor 1 and a speed changing mechanism 2 are arranged in the cover body 3, the speed changing mechanism 2 is connected with a conveying hopper, particulate materials in the specific discharging pipes fall into the conveying hopper, the driving motor 1 rotates, the motor 1 drives the conveying hopper to rotate, and accordingly particulate materials in the conveying hopper are conveyed into the discharging pipe below, the speed changing mechanism 2 in fig. 1 is a chain wheel and chain speed changing mechanism, a small chain wheel is connected with a motor shaft of the motor 1, a large chain wheel is connected with the conveying hopper through a wheel shaft, and a chain is sleeved on the outer sides of the large chain wheel and the small chain wheel. When a large amount of granular materials are accumulated in the conveying hopper to cause the motor to stop rotating, the rotating speed of the motor is 0 rotation, torque is still output, the current (called stop rotating current) during stop rotating can be 7 times of rated current, and the motor is burnt out after a little time, so that the embodiment of the utility model judges whether the motor stops rotating or not according to the characteristic that the motor generates large stop rotating current during stop rotating, and controls the motor to change the motion state during stop rotating according to two schemes of motor overcurrent and motor heating, thereby solving the problem of stop rotating.

As shown in fig. 2, the locked rotor control circuit of the embodiment of the utility model comprises a detection element, a DCS control unit and a motor forward/reverse rotation circuit, wherein the detection element is used for acquiring a signal of the motor, and the signal is a current signal or a thermal signal;

the DCS control unit is connected with the detection element and is used for receiving the signal acquired by the detection element, so as to judge whether the motor is blocked or not according to the signal; specifically, for example, the detected signal is a current signal, and the phenomenon of locked rotor appears when the detected current signal exceeds 1.5 times of rated current is set, so that whether the condition of locked rotor of the motor appears can be judged according to the relation between the detected current signal and the rated current signal; for example, the detected signal is a thermal signal, and the phenomenon of locked rotor appears when the detected temperature of the motor bearing exceeds 1.5 times of the normal temperature of the motor bearing is set, so that whether the motor has locked rotor can be judged according to the relation between the detected thermal signal and the normal thermal signal of the motor bearing;

the motor forward and backward rotation circuit comprises a motor forward and backward rotation working circuit and a motor forward and backward rotation control circuit, wherein the motor forward and backward rotation control circuit is used for controlling a motor of the motor forward and backward rotation working circuit to forward rotate, backward rotate or stop rotating, the DCS control unit is connected with the motor forward and backward rotation control circuit and used for controlling the motor forward and backward rotation control circuit, so that the motor forward and backward rotation control circuit is convenient to control the motor to switch the running state of the motor in the process of blocking rotation, and particularly, when the DCS control system judges that the motor is blocked in the forward rotation process, the DCS control system sends a control command to control the motor forward and backward rotation control circuit to stop rotating, the DCS control system controls the motor to reversely rotate again after stopping rotating, the reverse rotation time can be set through the DCS control system according to actual needs, the motor is stopped after a period of reverse rotation, and the motor forward rotation is controlled again to start normal feeding.

Specifically, the detection unit detects a current signal or a heat signal of the motor and sends the detected signal to the DCS control system, the DCS control system judges whether the motor has a locked-rotor condition according to the detected data and preset judging conditions, and when the locked-rotor condition is judged to occur, the DCS control system sends a control instruction to the motor forward and reverse rotation control circuit, so that the motor forward and reverse rotation control circuit controls the motor to switch the running state; the DCS control system is a distributed control system commonly used in the control field.

In a specific embodiment, as shown in fig. 2 and 4, the motor forward/reverse rotation control circuit includes a forward rotation control circuit, a reverse rotation control circuit and a scram control circuit disposed between a control line L1 and a zero line N;

the DCS forward rotation control circuit is provided with a DCS forward rotation normally-open contact 03, an SB1 forward rotation button and a normally-open contact of an alternating current contactor KM1, both ends of the DCS forward rotation normally-open contact 03 and both ends of the normally-open contact of the alternating current contactor KM1 are connected in parallel with both ends of the SB1 forward rotation button, one end of the SB1 forward rotation button is connected with a control line L1, and a normally-closed contact of an alternating current contactor KM2, a coil of the alternating current contactor KM1 and a normally-closed contact of a current relay KA1 are sequentially connected between the other end of the SB1 forward rotation button and a zero line N;

the reversing control circuit is provided with a DCS reversing normally open contact 04, an SB2 reversing button and a normally open contact of an alternating current contactor KM2, wherein both ends of the DCS reversing normally open contact 04 and both ends of the normally open contact of the alternating current contactor KM2 are connected in parallel with both ends of the SB2 reversing button, one end of the SB2 reversing button is connected with a control line L1, the other end of the SB2 reversing button is connected with one end of a normally closed contact of the alternating current contactor KM1, the other end of the normally closed contact of the alternating current contactor KM1 is connected with one end of a coil of the alternating current contactor KM2, and one end of the coil of the alternating current contactor KM1 is connected between the coil of the alternating current contactor KM1 and the normally closed contact of a current relay KA 1;

the quick stop control circuit is provided with a DCS stop button 05 and an SB3 quick stop button, the DCS stop button 05 is connected with the SB3 quick stop button in parallel, one end of the SB3 quick stop button is connected with the control line L1, the other end of the SB3 quick stop button is connected with one end of a coil of the current relay KA1, and the other end of the coil of the current relay KA1 is connected to the zero line N;

the DCS forward rotation normally open contact 03, the DCS reverse rotation normally open contact 04 and the DCS stop button 05 are all connected with the DCS control unit;

as shown in fig. 3 and 5, the motor forward and reverse rotation working circuit is provided with a normally open contact of the ac contactor KM1 and a normally open contact of the ac contactor KM2, when the normally open contact of the ac contactor KM1 is closed, the motor rotates forward, and when the normally open contact of the ac contactor KM2 is closed, the motor rotates reversely.

Specifically, press SB1 corotation button, the coil of corotation control circuit's alternating current contactor KM1 gets the electricity, alternating current contactor KM 1's normally open contact is closed, the motor begins corotation material conveying, when the motor corotation in-process DCS control system judges motor stall according to detecting element's signal, DCS control system sends control command at first and makes the motor stop rotating, then DCS control system sends control quality again and makes the motor begin to reverse, after the motor reverses for a certain time, for example set for the time of reversal for 25 seconds through DCS control system, send command through DCS control system again and make the motor stop rotating, finally make the motor normally begin corotation through DCS control system send command.

During implementation, the DCS normal rotation normally open contact 03, the DCS reverse rotation normally open contact 04 and the DCS stop button 05 can be set to be click buttons, namely, buttons which can be automatically reset after being released are pressed down, so that the specific control process is as follows: the DCS control system firstly sends a control instruction to a DCS stop button 05, after the DCS stop button 05 is closed, a coil of a current relay KA1 on the scram control circuit is electrified, so that a normally closed contact of the current relay KA1 is disconnected, the normally closed contact of the current relay KA1 is disconnected, so that both a coil of an alternating current contactor KM1 and a coil of an alternating current contactor KM2 are powered off, a motor stops rotating, the DCS stop button 05 is reset after the DCS stop button 05 is released, the coil of the current relay KA1 on the scram control circuit is powered off, and the normally closed contact of the current relay KA1 is closed again; after the motor stops rotating, the DCS control system sends a control instruction to the DCS reverse normally open contact 04, the DCS reverse normally open contact 04 is closed, a coil of the alternating current contactor KM2 is electrified, the normally open contact of the alternating current contactor KM2 is closed, the motor starts reversing, after the DCS reverse normally open contact 04 is loosened, the DCS reverse normally open contact 04 is reset, but because the normally open contact of the alternating current contactor KM2 is closed, the motor is still in a reverse state, after the motor reverses for a certain period of time, for example, after the DCS control system sets the reverse time to 25 seconds, the DCS control system sends a control instruction to the DCS stop button 05 to enable the DCS stop button 05 to be loosened after being closed again, the motor stops rotating, and finally, the DCS control system sends a control instruction to the DCS forward rotating button to enable the motor to normally start forward rotation.

In the above embodiment, since the motor is blocked in the forward rotation process, after the motor is controlled to reversely rotate and process the piled materials, the normal feeding can be realized by controlling the motor to rotate forward again, the motor is stopped for a short time, and the blanking pipe is not required to be disassembled.

In a specific embodiment, as shown in fig. 2, the detection element is a temperature detection resistor 02, in this embodiment, the temperature detection resistor 02 is used for detecting the temperature of the motor bearing, the DCS control system receives the temperature, and two ends of the temperature detection resistor 02 are respectively connected with the 11 output end and the 14 output end of the protection relay 01; the power supply A1 end of the protection relay 01 is connected to the control line L1, and the power supply A2 end of the protection relay 01 is connected to the zero line N, and specifically, for example, the temperature detection resistor 02 is set as a thermistor.

In a specific embodiment, as shown in fig. 2, the protection relay further includes an ac relay KA2, the T1 end of the protection relay 01 is connected to the control line L1, the T2 end of the protection relay 01 is connected to one end of the coil of the current relay KA2, and the other end of the coil of the current relay KA2 is connected to the neutral line N; the normally closed contact of the current relay KA2 is arranged between the normally closed contact of the current relay KA1 and the neutral line N. In this embodiment, the current relay KA2 is configured to perform a protection function, and specifically, when the DCS stop button 05 receives that a control command of the DCS control system cannot be normally closed, the coil of the current relay KA2 is powered on by the protection relay 01, and then the normally closed contact of the current relay KA2 is opened, so that the motor can also stop rotating.

In a specific embodiment, as shown in fig. 5, the detecting element is a current transformer 06, a primary winding of the current transformer 06 is connected in series on the motor forward and backward rotation working circuit, and an ammeter is connected between two ends of a secondary winding of the current transformer 06.

In a specific embodiment, as shown in fig. 4 to 5, two ends of the ammeter are respectively connected with the control line L1 and the zero line N, the control line L1 is connected with one end of the secondary winding of the current transformer 06, and the zero line N is connected with the other end of the secondary winding of the current transformer 06.

In a specific embodiment, the control line L1 is connected to one end of a normally open contact of the ac contactor KM1, the other end of the normally open contact of the ac contactor KM1 is connected to one end of a forward rotation indicator lamp, and the other end of the forward rotation indicator lamp is connected to the zero line N; the control line L1 is connected with one end of a normally open contact of the alternating current contactor KM2, the other end of the normally open contact of the alternating current contactor KM2 is connected with one end of a reverse indicator lamp, and the other end of the reverse indicator lamp is connected with the zero line N; the control line L1 is connected with one end of a normally closed contact of an alternating current contactor KM1, the other end of the normally closed contact of the alternating current contactor KM1 is connected with one end of a normally closed contact of an alternating current contactor KM2, the other end of the normally closed contact of the alternating current contactor KM2 is connected with one end of a scram indicator lamp, and the other end of the scram indicator lamp is connected with a zero line N.

In this embodiment, the setting of corotation pilot lamp, reversal pilot lamp and scram pilot lamp is convenient for directly perceivedly know the running state of motor.

In a specific embodiment, a breaker QF is arranged on the motor forward and backward rotation working circuit.

In a specific embodiment, the motor forward and backward rotation working circuit is provided with a thermal element of a thermal relay FR, and a normally closed contact of the thermal relay FR is arranged between a connection point of the reverse rotation control circuit and the forward rotation control circuit and a normally closed contact of the current relay KA 1.

In a specific embodiment, the number of normally open contacts of the ac contactor KM1 and the number of normally open contacts of the ac contactor KM2 on the motor forward and backward rotation operation circuit are 3, wherein: two ends of a normally open contact of a first alternating current contactor KM1 are respectively connected between a power line A and a U-phase line of the motor, two ends of a normally open contact of the second alternating current contactor KM1 are respectively connected between a power line B and a V-phase line of the motor, and two ends of a normally open contact of a third alternating current contactor KM1 are respectively connected between a power line C and a W-phase line of the motor; the two ends of the normally open contact of the first alternating current contactor KM2 are respectively connected between the power line A and the W phase line of the motor, the two ends of the normally open contact of the second alternating current contactor KM2 are respectively connected between the power line B and the V phase line of the motor, and the two ends of the normally open contact of the third alternating current contactor KM2 are respectively connected between the power line C and the U phase line of the motor.

In a specific embodiment, the control line L1 is provided with a fuse FU, which is located upstream of the forward rotation control circuit, the reverse rotation control circuit, and the scram control circuit.

It is noted that unless otherwise indicated, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this utility model pertains.

Furthermore, the terms "a," "an," "the" and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. In the description of the present utility model, the meaning of "plurality" is two or more unless specifically defined otherwise.

In this application, unless specifically stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model, and are intended to be included within the scope of the appended claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present utility model is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims (10)

1. A stall control circuit, comprising:

the detection element is used for acquiring signals of the motor;

the DCS control unit is connected with the detection element and is used for receiving the signals acquired by the detection element and judging whether the motor is locked or not according to the received signals acquired by the detection element;

the motor forward and backward rotation circuit comprises a motor forward and backward rotation working circuit and a motor forward and backward rotation control circuit, the DCS control unit is connected with the motor forward and backward rotation control circuit and used for controlling the motor forward and backward rotation control circuit, and the DCS control unit is convenient for switching the motor running state when the motor is controlled by the motor forward and backward rotation control circuit to stop rotating.

2. The locked rotor control circuit of claim 1 wherein the motor forward and reverse rotation control circuit comprises a forward rotation control circuit, a reverse rotation control circuit, and a scram control circuit disposed between a control line L1 and a zero line N;

the DCS forward rotation control circuit is provided with a DCS forward rotation normally-open contact, an SB1 forward rotation button and a normally-open contact of an alternating current contactor KM1, both ends of the DCS forward rotation normally-open contact and both ends of the normally-open contact of the alternating current contactor KM1 are connected in parallel with both ends of the SB1 forward rotation button, one end of the SB1 forward rotation button is connected with a control line L1, and a normally-closed contact of an alternating current contactor KM2, a coil of the alternating current contactor KM1 and a normally-closed contact of a current relay KA1 are sequentially connected between the other end of the SB1 forward rotation button and a zero line N;

the reversing control circuit is provided with a DCS reversing normally open contact, an SB2 reversing button and a normally open contact of an alternating current contactor KM2, both ends of the DCS reversing normally open contact and both ends of the normally open contact of the alternating current contactor KM2 are connected in parallel with both ends of the SB2 reversing button, one end of the SB2 reversing button is connected with a control line L1, the other end of the SB2 reversing button is connected with one end of a normally closed contact of the alternating current contactor KM1, the other end of the normally closed contact of the alternating current contactor KM1 is connected with one end of a coil of the alternating current contactor KM2, and one end of the coil of the alternating current contactor KM1 is connected between the coil of the alternating current contactor KM1 and the normally closed contact of the current relay KA 1;

the emergency stop control circuit is provided with a DCS (distributed control system) stop button and an SB3 emergency stop button, the DCS stop button is connected with the SB3 emergency stop button in parallel, one end of the SB3 emergency stop button is connected with the control line L1, the other end of the SB3 emergency stop button is connected with one end of a coil of the current relay KA1, and the other end of the coil of the current relay KA1 is connected to the zero line N;

the DCS forward rotation normally open contact, the DCS reverse rotation normally open contact and the DCS stop button are all connected with the DCS control unit;

the motor forward and backward rotation working circuit is provided with a normally open contact of an alternating current contactor KM1 and a normally open contact of an alternating current contactor KM2, when the normally open contact of the alternating current contactor KM1 is closed, the motor rotates forward, and when the normally open contact of the alternating current contactor KM2 is closed, the motor rotates backward.

3. The locked rotor control circuit according to claim 2, wherein the detecting element is a temperature detecting resistor, and two ends of the temperature detecting resistor are respectively connected with an 11 output end and a 14 output end of the protection relay;

the power A1 end of the protection relay is connected with the control line L1, and the power A2 end of the protection relay is connected with the zero line N.

4. The locked rotor control circuit of claim 3 further comprising an ac relay KA2, wherein the T1 end of the protection relay is connected to the control line L1, wherein the T2 end of the protection relay is connected to one end of a coil of the current relay KA2, and wherein the other end of the coil of the current relay KA2 is connected to the neutral line N;

the normally closed contact of the current relay KA2 is arranged between the normally closed contact of the current relay KA1 and the neutral line N.

5. The locked rotor control circuit of claim 2, wherein the detection element is a current transformer, a primary winding of the current transformer is connected in series with the motor forward and reverse rotation operation circuit, and an ammeter is connected between two ends of a secondary winding of the current transformer.

6. The locked rotor control circuit of claim 5 wherein the two ends of the ammeter are connected to the control line L1 and the neutral line N, respectively, the control line L1 being connected to one end of the secondary winding of the current transformer and the neutral line N being connected to the other end of the secondary winding of the current transformer.

7. The locked rotor control circuit according to claim 2, wherein the control line L1 is connected with one end of a normally open contact of an ac contactor KM1, the other end of the normally open contact of the ac contactor KM1 is connected with one end of a forward rotation indicator lamp, and the other end of the forward rotation indicator lamp is connected with the zero line N;

the control line L1 is connected with one end of a normally open contact of the alternating current contactor KM2, the other end of the normally open contact of the alternating current contactor KM2 is connected with one end of a reverse indicator lamp, and the other end of the reverse indicator lamp is connected with the zero line N;

the control line L1 is connected with one end of a normally closed contact of an alternating current contactor KM1, the other end of the normally closed contact of the alternating current contactor KM1 is connected with one end of a normally closed contact of an alternating current contactor KM2, the other end of the normally closed contact of the alternating current contactor KM2 is connected with one end of a scram indicator lamp, and the other end of the scram indicator lamp is connected with a zero line N.

8. The locked rotor control circuit according to claim 2, wherein a circuit breaker QF is provided on the motor forward and reverse operation circuit, a thermal element of a thermal relay FR is provided on the motor forward and reverse operation circuit, and a normally closed contact of the thermal relay FR is provided between a connection point of the reverse rotation control circuit and the forward rotation control circuit and a normally closed contact of the current relay KA 1.

9. The locked rotor control circuit of claim 2, wherein the number of normally open contacts of the ac contactor KM1 and the number of normally open contacts of the ac contactor KM2 in the motor forward and reverse operation circuit are 3, wherein:

two ends of a normally open contact of a first alternating current contactor KM1 are respectively connected between a power line A and a U-phase line of the motor, two ends of a normally open contact of the second alternating current contactor KM1 are respectively connected between a power line B and a V-phase line of the motor, and two ends of a normally open contact of a third alternating current contactor KM1 are respectively connected between a power line C and a W-phase line of the motor;

the two ends of the normally open contact of the first alternating current contactor KM2 are respectively connected between the power line A and the W phase line of the motor, the two ends of the normally open contact of the second alternating current contactor KM2 are respectively connected between the power line B and the V phase line of the motor, and the two ends of the normally open contact of the third alternating current contactor KM2 are respectively connected between the power line C and the U phase line of the motor.

10. The locked rotor control circuit of claim 2 wherein a fuse FU is provided on the control line L1, the fuse being upstream of the forward, reverse and scram control circuits.

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