Forced air cooling low-voltage variable-frequency motor control system
By connecting the forced air-cooled motor control circuit in the variable frequency motor control circuit, the series structure of the circuit breaker, AC contactor and relay is used to solve the problem of lack of interlocking control between the forced air-cooled low-voltage variable frequency motor and the main motor, and realizes the Correct start-stop interlocking protects the main motor and simplifies the operation process.
Patent Information
- Application Number
- CN202420033080.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-08
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-01-08
AI Technical Summary
The lack of interlocking control between the forced air-cooled low-voltage frequency converter motor and the main motor leads to the failure of the main motor to stop in time in the event of a failure, which can easily cause serious consequences such as burning.
The forced air-cooled motor control circuit is connected in the frequency converter main motor control circuit. By connecting the auxiliary contacts of the circuit breaker, the AC contactor coil and the auxiliary contacts of the intermediate relay, the interlocking start-stop control of the main motor and the forced air-cooled motor to avoid the need for a long time. The operation sequence is incorrect.
The correct interlocking and starting and stopping of the forced air-cooled motor and the main motor is achieved, which protects the main motor, simplifies the operation process, and prevents serious consequences such as motor burning due to incorrect operation sequence.
Smart Images
Figure CN222262515U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of electrical appliances, and in particular relates to a forced air-cooled low-voltage variable-frequency motor control system. Background Art
[0002] At present, variable frequency motors are widely used in metallurgy, chemical industry, papermaking, machinery and other industries. Among them, the forced air-cooled variable frequency motor cooling method contains an independently driven fan controlled by an independent power supply.
[0003] For forced air-cooled low-voltage variable frequency motors, when the forced air-cooling fan stops due to a motor or line fault, and the main motor continues to run, the main motor cannot be cooled and burns out. Therefore, it is required that the forced air-cooling motor should be started before the variable frequency motor is started; when the variable frequency main motor stops, the main motor should be stopped first and then the forced air-cooling motor; when the forced air-cooling motor stops for some reason, its main motor should also be stopped immediately. Usually, the main motor and the forced air-cooling motor at the project site are controlled by their own operating columns to start and stop the motors, and there is no interlocking between the main motor and the forced air-cooling motor, which can easily cause the main motor to burn out or even more serious consequences. Summary of the invention
[0004] In order to solve the problem that the forced air-cooled motor and the main motor cannot be interlocked for start and stop, the utility model provides a forced air-cooled low-voltage variable-frequency motor control system.
[0005] The utility model provides a forced air-cooled low-voltage variable frequency motor control system, which includes a forced air-cooled motor control circuit connected in parallel at the lower end of a control switch a of a variable frequency main motor control circuit, and the circuit is mainly composed of auxiliary contacts of a circuit breaker b of the forced air-cooled motor and an AC contactor coil connected in series.
[0006] As an improved solution, an AC contactor main contact is connected in series on the lower side of the circuit breaker b of the forced air-cooled motor.
[0007] As a further improved solution, an AC contactor auxiliary contact a is connected in series between the lower end of the auxiliary contact of the intermediate relay b in the control circuit of the main motor and the upper end of the coil of the intermediate relay a.
[0008] The utility model has the following beneficial effects:
[0009] 1) Forced air-cooled motors can correctly interlock the start and stop of the main motor, thus protecting the main motor.
[0010] 2) Forced air-cooled motors no longer require a separate operating column, which simplifies the operating procedures for on-site workers.
[0011] 3) Prevent motor burnout or even more serious consequences due to incorrect operating sequence of the variable frequency main motor operating column and the forced air cooling motor operating column. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is the main circuit diagram of the utility model;
[0013] Figure 2 This is the control circuit diagram of the frequency conversion main motor and forced air cooling motor of the utility model;
[0014] Figure 3 This is the circuit diagram of the control loop of the forced air-cooled motor of the utility model;
[0015] Figure 4 This is the wiring terminal diagram of the inverter of the utility model.
[0016] In the figure: 1-circuit breaker a, 2-circuit breaker b, 3-control switch a, 4-control switch b, 5-auxiliary contact of circuit breaker b, 6-motor protector, 7-auxiliary contact a of motor protector, 8-AC contactor coil, 9-AC contactor main contact, 10-auxiliary contact a of AC contactor, 11-intermediate relay a coil, 12-auxiliary contact of intermediate relay a (1), 13-auxiliary contact of intermediate relay a (2), 14-auxiliary contact of intermediate relay a (3), 15-intermediate relay b coil, 16-auxiliary contact of intermediate relay b, 17-intermediate relay c coil, 18-intermediate relay b coil Auxiliary contacts of relay c, 19-frequency converter, 20-frequency converter auxiliary contact a, 21-frequency converter auxiliary contact b, 22-cooling fan, 23-signal light a, 24-signal light b, 25-signal light c, 26-shunt release coil of circuit breaker b, 27-AC contactor auxiliary contact b, 28-AC contactor auxiliary contact c, 29-motor protector auxiliary contact b, 30-fuse a, 31-fuse b, 32-fuse c, 33-fuse d, 34-fuse e, 35-current transformer, 36-residual current transformer, 37-forced air-cooled motor, 38-main motor. DETAILED DESCRIPTION
[0017] The utility model is further described below in conjunction with the accompanying drawings.
[0018] like Figures 1 to 4 A forced air-cooled low-voltage variable frequency motor control system, in which a forced air-cooled motor control circuit is connected in parallel at the lower end of the variable frequency main motor control circuit control switch a3, and the circuit is mainly composed of the auxiliary contact 5 of the circuit breaker b of the forced air-cooled motor and the AC contactor coil 8 connected in series.
[0019] An AC contactor main contact 9 is connected in series on the lower side of the circuit breaker b2.
[0020] An AC contactor auxiliary contact a10 is connected in series between the lower end of the auxiliary contact 16 of the intermediate relay b of the control loop and the upper end of the coil 11 of the intermediate relay a.
[0021] When circuit breaker a1 and circuit breaker b2 are closed, the auxiliary contact 5 of circuit breaker b is closed accordingly, and the control switch a3 is pressed, the AC contactor coil 8 is energized, the AC contactor main contact 9 of the forced air-cooled motor main circuit is closed, and the forced air-cooled motor starts. At the same time, the AC contactor auxiliary contact a10 of the control circuit is closed; the inverter self-checks that there is no internal fault and sends out the inverter permission signal, the inverter auxiliary contact a20 is closed, the intermediate relay b coil 15 is energized, and the auxiliary contact 16 of the intermediate relay b is closed. At this time, the intermediate relay a coil 11 is energized, and the auxiliary contact (2) 13 of the intermediate relay a connected to the inverter "start / stop" terminal is closed, the inverter starts, and the main motor starts. The auxiliary contact (1) 12 of the intermediate relay a is closed to self-hold the starting circuit, and the main motor and the forced air-cooled motor enter the self-locking continuous operation state.
[0022] When the control switch b4 is pressed, the coil 11 of the intermediate relay a in the control circuit loses power, the auxiliary contact (2) 13 of the intermediate relay a connected to the "start / stop" terminal of the inverter is disconnected, and the main motor stops running; the auxiliary contact (1) 12 of the self-holding intermediate relay a in the control circuit opens, the forced air-cooled motor control circuit is disconnected, the AC contactor coil 8 loses power, the AC contactor main contact 9 opens, and the forced air-cooled motor stops running.
[0023] When a short circuit fault occurs in the forced air-cooled motor, the circuit breaker b of the forced air-cooled motor trips, the auxiliary contact 5 of the fan control circuit breaker b is disconnected, the AC contactor coil 8 loses power, the AC contactor main contact 9 and the AC contactor auxiliary contact a 10 are both disconnected, the forced air-cooled motor stops running, the control circuit intermediate relay a coil 11 also loses power, and the main motor stops running.
[0024] When an overload fault occurs in the forced air-cooled motor, the auxiliary contact a7 of the motor protector is disconnected, and the AC contactor coil 8 loses power, then the forced air-cooled motor and the main motor both stop running as described above.
[0025] When a single-phase grounding fault occurs in the forced air-cooled motor, the auxiliary contact b29 of the motor protector is closed, the shunt release coil 26 of the circuit breaker b is energized, the circuit breaker b is disconnected, and the forced air-cooled motor and the main motor stop running.
[0026] The above is only a typical example of the utility model, and does not impose any formal limitation on the utility model. Any technician familiar with the profession, without departing from the scope of the technical solution of the utility model, shall be regarded as an equivalent example of equivalent changes made by using the above technical content. Any equivalent changes made to the above examples based on the technical essence of the utility model without departing from the content of the technical solution of the utility model shall fall within the scope of the technical solution of the utility model.
Claims
1. A forced air-cooled low-voltage variable-frequency motor control system, characterized in that: The system includes a forced air-cooling motor control circuit connected in parallel at the lower end of the control switch a of the variable frequency main motor control circuit, and the circuit includes the auxiliary contact of the circuit breaker b of the forced air-cooling motor and the AC contactor coil connected in series therewith; an AC contactor main contact is connected in series at the lower side of the circuit breaker b, and an AC contactor auxiliary contact a is connected in series at the lower end of the auxiliary contact of the intermediate relay b of the control circuit of the main motor and the upper end of the coil of the intermediate relay a.
2. The forced air-cooled low-voltage variable-frequency motor control system according to claim 1 is characterized in that: The control system also includes an auxiliary contact (1) of an intermediate relay a connected in parallel with the control switch a. When the auxiliary contact (1) of the intermediate relay a is closed, the starting circuit is self-maintained, and the main motor and the forced air-cooled motor enter a self-locking continuous operation state.