CN215344410U - Soft start system of low-voltage high-power alternating current motor - Google Patents
Soft start system of low-voltage high-power alternating current motor Download PDFInfo
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- CN215344410U CN215344410U CN202121557213.6U CN202121557213U CN215344410U CN 215344410 U CN215344410 U CN 215344410U CN 202121557213 U CN202121557213 U CN 202121557213U CN 215344410 U CN215344410 U CN 215344410U
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Abstract
The utility model provides a soft start-up system of high-power AC motor of low pressure includes: circuit breaker, converter, main contactor and programmable controller, the inlet wire of circuit breaker is connected with the power supply of motor, converter and main contactor are parallelly connected to be set up, and the inlet wire of converter and main contactor's inlet wire all with the play line connection of circuit breaker, being qualified for the next round of competitions of converter and main contactor is qualified for the next round of competitions and all is connected with the inlet wire of motor, wherein, the inlet wire of converter end and leading-out terminal are provided with first contactor and second contactor respectively, and first contactor, converter and second contactor are established ties and is set up, and the power of converter is less than the power of motor, programmable controller is connected with converter, main contactor, first contactor and second contactor electricity respectively to can be according to the feedback signal control main contactor of converter, first contactor and disconnection of second contactor or actuation, wherein, converter and main contactor do not work simultaneously, the real-time frequency of operation of feedback signal sign motor.
Description
Technical Field
The application relates to the technical field of motor soft start, in particular to a soft start system of a low-voltage high-power alternating current motor.
Background
In the production of large-specification hot-rolled bars, a main motor (380V, 500Kw) of a hot saw is a low-voltage high-power motor, a conventional low-voltage soft starting device is adopted in a traditional starting mode, the rated current of the motor is nearly 1000A, the power of the configured soft starting device is high, the current of the configured soft starting device is high, although the soft starting device is configured, the working current still reaches thousands of amperes during starting, the service life of the soft starting device is not long due to high-current impact, the cost is high, the impact on a power grid is quite large, and the voltage of the power grid is unstable. When the soft start device is damaged, the soft start device must be stopped, and the smooth production is greatly influenced.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
SUMMERY OF THE UTILITY MODEL
The present application is directed to a soft start system for a low-voltage high-power ac motor, so as to solve or alleviate the above-mentioned problems in the prior art.
In order to achieve the above purpose, the present application provides the following technical solutions:
the application provides a soft start-up system of high-power alternating current motor of low pressure includes: the circuit breaker, the frequency converter, the main contactor and the programmable controller; the incoming line of the circuit breaker is connected with a power supply of the motor; the frequency converter is connected with the main contactor in parallel, an incoming line of the frequency converter and an incoming line of the main contactor are both connected with an outgoing line of the circuit breaker, and an outgoing line of the frequency converter and an outgoing line of the main contactor are both connected with an incoming line of the motor; the system comprises a frequency converter, a motor, a first contactor, a second contactor, a third contactor, a fourth contactor, a fifth contactor, a sixth contactor, a motor and a fourth contactor, wherein the incoming line end and the outgoing line end of the frequency converter are respectively provided with the first contactor and the second contactor, the first contactor, the frequency converter and the second contactor are arranged in series, and the power of the frequency converter is smaller than that of the motor; the programmable controller is respectively electrically connected with the frequency converter, the main contactor, the first contactor and the second contactor, and can control the main contactor, the first contactor and the second contactor to be disconnected or attracted according to a feedback signal of the frequency converter; the frequency converter and the main contactor do not work simultaneously, and the feedback signal represents the real-time working frequency of the motor.
Preferably, the working mode of the frequency converter is a V/F mode.
Preferably, when the motor is started, the programmable controller controls the first contactor and the second contactor to be attracted, and controls the main contactor to be disconnected; and the frequency converter monitors the working frequency of the motor in real time and sends the feedback signal to the programmable controller according to the monitored real-time working frequency of the motor.
Preferably, the frequency converter compares the monitored real-time working frequency of the motor with a preset working frequency, responds that the real-time working frequency of the motor is greater than or equal to the preset working frequency, and sends the feedback signal to the programmable controller so that the programmable controller controls the first contactor and the second contactor to be disconnected and controls the main contactor to be closed.
Preferably, the preset working frequency ranges from 51 to 52 Hz.
Preferably, the power of the motor is 500Kw, and the power of the frequency converter is 160 Kw.
Has the advantages that:
in the technical scheme provided by the embodiment of the application, a frequency converter is connected with a main contactor in parallel, a first contactor and a second contactor are respectively arranged at an inlet wire end and an outlet wire end of the frequency converter, a programmable controller controls the disconnection or the attraction of the first contactor, the second contactor and the main contactor, so that only one of the frequency converter and the main contactor is in a working state at the same time, when a motor is started, the programmable controller controls the disconnection of the main contactor, the first contactor and the second contactor are attracted, the frequency converter works, the motor is started with a small starting current, meanwhile, the frequency converter monitors the working frequency of the motor in real time, after the working frequency of the motor reaches a preset frequency threshold value, the frequency converter sends a feedback signal to the programmable controller, the programmable controller controls the disconnection of the first contactor and the second contactor and controls the attraction of the main contactor at the same time, and bypassing the frequency converter, and finishing the soft start of the motor. Therefore, when the motor is started, the working frequency is slowly increased until the rated working frequency of the motor is reached, the main contactor is switched to work, the frequency converter is bypassed, in the process, the starting current of the motor is changed from zero, and the maximum value does not exceed the rated current, so that the impact on a power grid and the requirement on power supply capacity are effectively reduced, the service life of equipment is prolonged, and the maintenance cost of the equipment is saved.
Meanwhile, the frequency converter only works when the motor is started, and after the motor is started, the frequency converter is bypassed, so that the power of the frequency converter is effectively reduced, the soft start of the motor is realized under the condition that the power of the frequency converter is far smaller than the power of the motor, the frequency converter is prevented from running all the time when the motor is started to run normally, and the system cost is reduced.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. Wherein:
fig. 1 is a schematic structural diagram of a soft start system of a low-voltage high-power ac motor according to some embodiments of the present application.
Description of reference numerals:
101-a circuit breaker; 102-a frequency converter; 103-a main contactor; 104-a first contactor; 105-a second contactor; 106-motor.
Detailed Description
The present application will be described in detail below with reference to the embodiments with reference to the attached drawings. The various examples are provided by way of explanation of the application and are not limiting of the application. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present application without departing from the scope or spirit of the application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. It is therefore intended that the present application cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
In the description of the present application, the terms "connected," "connected," and "disposed" are used in a broad sense, and may be, for example, fixedly connected or detachably connected; can be directly connected or indirectly connected through intermediate components; the connection may be a wired electrical connection, a wireless electrical connection, or a wireless communication signal connection, and a person skilled in the art can understand the specific meaning of the above terms according to specific situations.
FIG. 1 is a schematic diagram of a soft start system for a low voltage high power AC motor according to some embodiments of the present application; as shown in fig. 1, the soft start system of the low-voltage high-power ac motor includes: a circuit breaker 101, a frequency converter 102, a main contactor 103 and a programmable controller. An incoming line of the circuit breaker 101 is connected with a power supply of the motor 106; the frequency converter 102 and the main contactor 103 are arranged in parallel, an incoming line of the frequency converter 102 and an incoming line of the main contactor 103 are both connected with an outgoing line of the circuit breaker 101, and an outgoing line of the frequency converter 102 and an outgoing line of the main contactor 103 are both connected with an incoming line of the motor 106; the incoming line end and the outgoing line end of the frequency converter 102 are respectively provided with a first contactor 104 and a second contactor 105, the first contactor 104, the frequency converter 102 and the second contactor 105 are arranged in series, and the power of the frequency converter 102 is smaller than that of the motor 106; the programmable controller is respectively electrically connected with the frequency converter 102, the main contactor 103, the first contactor 104 and the second contactor 105, and can control the main contactor 103, the first contactor 104 and the second contactor 105 to be disconnected or attracted according to the feedback signal of frequency conversion; wherein, the frequency converter 102 and the main contactor 103 do not work at the same time, and the feedback signal represents the real-time working frequency of the motor 106.
In the embodiment of the application, the circuit breaker 101 is arranged on the power supply line of the motor 106, so that on one hand, the system is powered off in the maintenance process, the system is ensured to be safely maintained under the condition of power off, and the safety of the system is improved; on the other hand, the circuit breaker 101 can automatically cut off the circuit when serious overload or short circuit (over-high current) or under-voltage (over-low voltage) occurs in the system, so as to effectively protect other equipment and further improve the safety of the system.
In the embodiment of the present application, the frequency converter 102 is in a V/F mode, i.e., a mode in which the voltage and the frequency are proportional to each other, so that the motor 106 can be effectively controlled to start with a small starting current, the starting current of the motor 106 changes from zero, and the maximum value does not exceed the rated current, thereby effectively alleviating the impact on the power grid and the requirement on the power supply capacity, prolonging the service life of the device, and saving the maintenance cost of the device.
In the embodiment of the application, when the motor 106 is started, the programmable controller controls the first contactor 104 and the second contactor 105 to be attracted, and controls the main contactor 103 to be disconnected; and the frequency converter 102 monitors the operating frequency of the motor 106 in real time and sends a feedback signal to the programmable controller according to the monitored real-time operating frequency of the motor 106. Further, the frequency converter 102 compares the monitored real-time operating frequency of the motor 106 with a preset operating frequency, and in response to that the real-time operating frequency of the motor 106 is greater than or equal to the preset operating frequency, the frequency converter 102 sends a feedback signal to the programmable controller, so that the programmable controller controls the first contactor 104 and the second contactor 105 to be disconnected, and controls the main contactor 103 to be closed. Specifically, the preset operating frequency is in the range of (51, 52) hertz.
In the embodiment of the present application, the preset working frequency may be set in the frequency converter 102, and in the starting process of the motor 106, the frequency converter 102 monitors the working frequency of the motor 106 in real time and compares the working frequency with the preset working frequency; when the operating frequency of the motor 106 reaches the preset frequency threshold, the frequency converter 102 sends a feedback signal to the programmable controller, and the programmable controller controls the first contactor 104, the second contactor 105 and the main contactor 103 to operate, so that the frequency converter 102 is bypassed.
In the embodiment of the present application, the power of the motor 106 is 500Kw, and the power of the frequency converter 102 is 160 Kw. Therefore, the frequency converter 102 only works when the motor 106 is started, and after the motor 106 is started, the frequency converter 102 is bypassed, so that the power of the frequency converter 102 is effectively reduced (the power of the frequency converter 102 is less than one third of the power of the motor 106), the soft start of the motor 106 is realized under the condition that the power of the frequency converter 102 is far less than the power of the motor 106, the frequency converter 102 is prevented from running all the time when the motor 106 is started to run normally, and the system cost is reduced; meanwhile, the small-power frequency converter 102 is smaller in size, smaller in occupied space and lower in cost, the frequency converter 102 only works in a short time (about 1 minute), no current impact exists in the working process, the motor 106 and the circuit breaker 101 stably run, and the service life is longer.
In the embodiment of the application, the frequency converter 102 is arranged in parallel with the main contactor 103, the incoming line end and the outgoing line end of the frequency converter 102 are respectively provided with the first contactor 104 and the second contactor 105, the programmable controller controls the first contactor 104, the second contactor 105 and the main contactor 103 to be opened or closed, so that only one of the frequency converter 102 and the main contactor 103 is in a working state at the same time, when the motor 106 is started, the programmable controller controls the main contactor 103 to be opened, the first contactor 104 and the second contactor 105 are closed, the frequency converter 102 works, so that the motor 106 is started with a small starting current, meanwhile, the frequency converter 102 carries out real-time monitoring on the working frequency of the motor 106, after the working frequency of the motor 106 reaches a preset frequency threshold, the frequency converter 102 sends a feedback signal to the programmable controller, the programmable controller controls the first contactor 104 and the second contactor 105 to be opened, and simultaneously, controlling the main contactor 103 to be attracted, enabling the frequency converter 102 to bypass, and ending the soft start of the motor 106. Therefore, when the motor 106 is started, the working frequency is slowly increased until the rated working frequency of the motor is reached, the main contactor 103 is switched to work, the frequency converter 102 is bypassed, in the process, the starting current of the motor 106 is changed from zero, and the maximum value does not exceed the rated current, so that the impact on a power grid and the requirement on power supply capacity are effectively reduced, the service life of equipment is prolonged, and the maintenance cost of the equipment is saved.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (6)
1. A soft start system of a low-voltage high-power alternating current motor is characterized by comprising: the circuit breaker, the frequency converter, the main contactor and the programmable controller;
the incoming line of the circuit breaker is connected with a power supply of the motor;
the frequency converter is connected with the main contactor in parallel, an incoming line of the frequency converter and an incoming line of the main contactor are both connected with an outgoing line of the circuit breaker, and an outgoing line of the frequency converter and an outgoing line of the main contactor are both connected with an incoming line of the motor; the system comprises a frequency converter, a motor, a first contactor, a second contactor, a third contactor, a fourth contactor, a fifth contactor, a sixth contactor, a motor and a fourth contactor, wherein the incoming line end and the outgoing line end of the frequency converter are respectively provided with the first contactor and the second contactor, the first contactor, the frequency converter and the second contactor are arranged in series, and the power of the frequency converter is smaller than that of the motor;
the programmable controller is respectively electrically connected with the frequency converter, the main contactor, the first contactor and the second contactor, and can control the main contactor, the first contactor and the second contactor to be disconnected or attracted according to a feedback signal of the frequency converter;
the frequency converter and the main contactor do not work simultaneously, and the feedback signal represents the real-time working frequency of the motor.
2. The soft start system of low voltage high power ac motor according to claim 1, wherein the operation mode of said inverter is V/F mode.
3. The soft start system of a low-voltage high-power alternating current motor as claimed in claim 1, wherein when the motor is started, the programmable controller controls the first contactor and the second contactor to be closed and controls the main contactor to be opened; and the frequency converter monitors the working frequency of the motor in real time and sends the feedback signal to the programmable controller according to the monitored real-time working frequency of the motor.
4. The soft start system of claim 3, wherein the inverter compares the monitored real-time operating frequency of the motor with a preset operating frequency, and in response to the real-time operating frequency of the motor being greater than or equal to the preset operating frequency, the inverter sends the feedback signal to the programmable controller, so that the programmable controller controls the first contactor and the second contactor to be turned off and controls the main contactor to be turned on.
5. The soft start system of claim 4, wherein the predetermined operating frequency is in the range of 51-52 Hz.
6. A soft start system for a low voltage high power AC motor according to any one of claims 1 to 5, wherein the power of said motor is 500Kw and the power of said inverter is 160 Kw.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121557213.6U CN215344410U (en) | 2021-07-08 | 2021-07-08 | Soft start system of low-voltage high-power alternating current motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121557213.6U CN215344410U (en) | 2021-07-08 | 2021-07-08 | Soft start system of low-voltage high-power alternating current motor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215344410U true CN215344410U (en) | 2021-12-28 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121557213.6U Active CN215344410U (en) | 2021-07-08 | 2021-07-08 | Soft start system of low-voltage high-power alternating current motor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215344410U (en) |
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2021
- 2021-07-08 CN CN202121557213.6U patent/CN215344410U/en active Active
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