Integrated motor starting cabinet

Abstract

The utility model discloses an integrated motor starting cabinet which comprises a starting cabinet body and a motor control system arranged in the cabinet body, the cabinet body comprises an element chamber, and the element chamber is divided into a front chamber and a rear chamber. The motor control system comprises a load switch-fuse combined electric appliance, a voltage transformer, a starting contactor, an electric reactor and a current transformer, is provided with a reactive compensation unit, and can be used for reducing the starting voltage of a motor and improving the power factor while controlling the starting of the motor. According to the integrated motor starting cabinet, the load switch-fuse combined electric appliance and the vacuum contactor are adopted to replace a traditional circuit breaker, the element chamber adopts the design of the front chamber and the rear chamber, the reactive power compensation unit and the starting cabinet are integrated, the installation space and the manufacturing cost are saved, the reactive power compensation unit can be freely selected and matched, and the application range is wide.

Description

Technical Field

[0001] The present application relates to the technical field of motor starting, and in particular to an integrated motor starting cabinet. Background Art

[0002] High-voltage motors with a rated voltage between 3 and 12 kV are often used in high-power output situations. These high-power output motors require large currents and torques when starting, so a starter cabinet is needed to control the motor's starting process. Traditional motors are mostly asynchronous motors. The equivalent circuit of an asynchronous motor can be regarded as a series circuit of resistance and inductance. The phase difference between its voltage and current is large, and the power factor is low. The method of parallel capacitors is often used to improve the power factor. Traditional starting cabinets are generally equipped with compensation cabinets and reactor cabinets. They are large in size and occupy a large area, which is not conducive to installation and maintenance. At the same time, traditional starting cabinets use circuit breakers as protection devices, and their manufacturing costs are high. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a new type of motor starter cabinet to solve the problem that the traditional starter cabinet is large in size and has high manufacturing cost. To achieve the above purpose, this application adopts the following solution:

[0004] The integrated motor starting cabinet comprises a starting cabinet body and a motor control system arranged inside the cabinet body, wherein the motor control system is used to reduce the motor starting voltage and control the motor starting.

[0005] Preferably, the motor control system comprises a load switch-fuse combination device consisting of a load switch and a first fuse connected in series, a voltage transformer, a starting contactor, a reactor and a current transformer;

[0006] Alternatively, the motor control system includes a load switch-fuse combination device consisting of a load switch and a first fuse connected in series, a voltage transformer, a starting contactor, a reactor, a reactive power compensation unit and a current transformer.

[0007] Preferably, it also includes an incoming cable and an outgoing cable, wherein the incoming cable, the load switch-fuse combination appliance, the starting contactor, the reactor, the current transformer and the outgoing cable are connected in series in sequence, the input end of the load switch is connected to the power grid through the incoming cable, the output end of the first fuse is connected to the input end of the starting contactor, the voltage transformer, an isolating switch and a second fuse are connected in series with each other and then connected in parallel between the first fuse and the starting contactor.

[0008] Further preferably, the isolating switch is logically interconnected with the load switch, and the on / off state of the isolating switch is controlled by the on / off state of the load switch.

[0009] Preferably, an operating contactor is connected in parallel at both ends of the reactor, and when the operating contactor is closed, it is used to cut the reactor out of the control system.

[0010] Further preferably, the starting contactor and the running contactor are vacuum contactors.

[0011] Preferably, the reactive power compensation unit is connected in parallel between the reactor and the starting contactor, and the reactive power compensation unit comprises a third fuse and a compensation capacitor group connected in series, and the compensation capacitor group comprises at least three groups of capacitors connected in parallel.

[0012] Preferably, it further comprises a lightning arrester, which is connected in parallel between the outgoing cable and the current transformer, and is grounded through a bottom line.

[0013] Preferably, the cabinet is provided with a cable room and a component room, and a contactor room and a reactor room are arranged side by side from top to bottom on one side of the cable room and the component room, and the component room includes a front room and a rear room, the reactive power compensation unit is arranged in the rear room, the load switch-fuse combination appliance, the voltage transformer, the second fuse, the isolating switch, the starting contactor, the current transformer and the lightning arrester are arranged in the front room, the incoming cable and the outgoing cable are arranged in the cable room, the running contactor is arranged in the contactor room, the reactor is arranged in the reactor room, and the reactor is installed at the bottom of the reactor room through a guide rail.

[0014] Beneficial effects:

[0015] (1) Low cost: using load switch-fuse combination appliances plus vacuum contactors to replace traditional circuit breakers, reducing manufacturing costs by 15%;

[0016] (2) The component room adopts a front and back two-chamber design, integrating the reactor cabinet, starting cabinet and reactive power compensation unit into the same cabinet, saving installation space and cost. The reactor in the reactor cabinet is installed on the guide rail for easy maintenance.

[0017] (3) Wide range of applications. The starting cabinet adopts a standardized design. The reactive power compensation unit is an optional part. You can choose to install a reactive power compensation unit to adapt to asynchronous motors, or you can choose a standard starting cabinet without a reactive power compensation unit to adapt to other motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the motor control system described in this application;

[0019] Figure 2 is a front schematic diagram of the integrated motor starter cabinet described in the present application;

[0020] Figure 3 It is a front internal structure diagram of the integrated motor starter cabinet described in this application;

[0021] Figure 4 This is a diagram of the internal structure of the back side of the integrated motor starter cabinet described in this application.

[0022] In the figure: 1-operating contactor, 2-outgoing cable, 3-incoming cable, 4-lightning arrester, 5-current transformer, 6-load switch, 7-reactor, 8-starting contactor, 9-voltage transformer, 10A-first fuse, 10B-second fuse, 10C-third fuse, 11-compensating capacitor bank, 12-isolating switch, 100-cabinet, 20, motor control system, 30-cable room, 40-component room, 50-contactor room, 60-reactor room. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings of the present application. Obviously, it should be noted that in the description of the embodiments of the present application, the terms "first" and "second" are only used to distinguish the descriptions and cannot be understood as indicating or implying the degree of their importance.

[0024] Combined with reference Figures 1 to 4 , the integrated motor starter cabinet described in this embodiment is described in detail. The starter cabinet includes a cabinet body 100 and a motor control system 20 arranged inside the cabinet body. The starter cabinet body 100 is provided with a cable chamber 30 and a component chamber 40. The cable chamber 30 is located at the upper end of the component chamber 40, and the component chamber 40 is divided into a front chamber and a rear chamber. On one side of the cable chamber 30 and the component chamber 40, a contactor chamber 50 and a reactor chamber 60 are arranged side by side from top to bottom. A dashboard is installed on the surface of the cabinet body 100, and a voltmeter and an ammeter that can be used to monitor voltage and current values ​​in different ranges are installed on the dashboard.

[0025] like Figure 1 As shown, the motor control system 20 includes a load switch-fuse combination consisting of a load switch 6 and a first fuse 10A connected in series, a voltage transformer 9, a starting contactor 8, a reactor 7 and a current transformer 5. The load switch-fuse combination, the starting contactor 8, the reactor 7 and the current transformer 5 are connected in series in sequence, and the input end of the load switch 6 is also connected to the power grid through an incoming cable 3, and the output end of the current transformer 5 is connected to an outgoing cable 2, and the outgoing cable 2 is used to connect to the motor to be started. The load switch-fuse combination is used to replace the circuit breaker used in the traditional starting cabinet to control the working state of the entire motor control system.

[0026] The voltage transformer 9 is connected in parallel between the starting contactor 8 and the first fuse 10A, and the voltage transformer 9 is also connected in series with an isolating switch 12 and a second fuse 10B to ensure the safe operation of the voltage transformer 9 and its connection circuit. The voltage transformer 9, the isolating switch 12 and the second fuse 10B are connected in series and connected in parallel between the starting contactor 8 and the first fuse 10A as a whole. The isolating switch 12 is grounded through a ground wire, and the isolating switch 12 is logically interconnected with the load switch 6. The on-off state of the isolating switch 12 is controlled by the on-off of the load switch 6. The voltage transformer 9 is used to convert the primary side voltage of the higher voltage level in the control system into a lower and standardized secondary side voltage, so that before starting, the power supply voltage can be monitored in real time through the voltmeter to confirm whether the input voltage is within the allowable range to ensure that the motor starts under normal voltage conditions. At the same time, it can also be used to continuously monitor the power supply voltage changes during the operation of the motor, so as to timely discover abnormal conditions such as voltage fluctuations, voltage loss or overvoltage, so as to trigger the protection device in the starting cabinet to ensure the safety and stability of the motor operation. Likewise, the current transformer 5 can convert a large current on the primary side into a small current on the secondary side, and the current is monitored by the ammeter.

[0027] A running contactor 1 is also connected in parallel at both ends of the reactor 7. The reactor 7 is used to limit the starting current of the motor when the motor starts, so that the motor smoothly transitions to the normal operation state. When the load switch 6 and the starting contactor 8 are closed, the running contactor 1 is kept in an open state, so that the reactor 7 is put into operation during the motor starting stage. When the motor starts and no longer needs to limit the current, the reactor 7 can be quickly cut out of the circuit by closing the running contactor 1. The running contactor 1 and the starting contactor 8 are vacuum contactors, which have the advantages of high power-off capability, short response time, and repeated breaking.

[0028] A lightning arrester 4 is also connected in parallel between the outgoing cable 2 and the current transformer 5. The lightning arrester 4 is grounded through a ground wire to transmit overvoltage to the ground for protecting the starter cabinet.

[0029] Since most of the loads used in the power system are asynchronous motors, and the equivalent circuit of the asynchronous motor can be regarded as a series circuit of resistance and inductance, the phase difference between its voltage and current is large, and the power factor is low. Therefore, in order to start the asynchronous motor in this embodiment, a reactive compensation unit is also provided. The reactive compensation unit reduces the phase difference between the voltage and current by offsetting part of the inductance current to improve the power factor. The reactive compensation unit is connected in parallel between the reactor 7 and the starting contactor 8. The reactive compensation unit includes a third fuse 10C connected in series and a compensation capacitor group 11. The compensation capacitor group 11 includes at least three groups of capacitors connected in parallel. The starting cabinet is a standardized design. When the reactive compensation unit is not provided, it can be used to start other motors other than asynchronous motors.

[0030] The incoming cable 3 and the outgoing cable 2 are arranged in the cable chamber 30, and are respectively connected to the power grid and the motor to be started through the incoming cable hole and the outgoing cable hole opened on the top of the cable chamber. The load switch-fuse combination appliance, the voltage transformer 9, the second fuse 10B, the isolating switch 12, the starting contactor 8, the current transformer 5 and the lightning arrester 4 are arranged in the front chamber, and the reactive power compensation unit is arranged in the rear chamber. The reactive power compensation unit is integrated with the starting cabinet to save installation space. The operating contactor 1 is arranged in the contactor chamber 50, and the reactor 7 is arranged in the reactor chamber 60, and the reactor 7 is installed at the bottom of the reactor chamber 60 through a guide rail, which is convenient for taking out or putting in from the starting cabinet, making maintenance more convenient.

[0031] The embodiments described in this application are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

Claims

1. Integrated motor starter cabinet, characterized by: It includes a starting cabinet body and a motor control system arranged inside the cabinet body, wherein the motor control system is used to reduce the motor starting voltage and control the motor starting; The motor control system comprises a load switch-fuse combination device consisting of a load switch and a first fuse connected in series, a voltage transformer, a starting contactor, a reactor and a current transformer; Alternatively, the motor control system includes a load switch-fuse combination consisting of a load switch and a first fuse connected in series, a voltage transformer, a starting contactor, a reactor, a reactive power compensation unit and a current transformer.

2. The integrated motor starter cabinet according to claim 1, characterized in that: The motor control system also includes an incoming cable and an outgoing cable. The incoming cable, the load switch-fuse combination appliance, the starting contactor, the reactor, the current transformer and the outgoing cable are connected in series in sequence. The input end of the load switch is connected to the power grid through the incoming cable, the output end of the first fuse is connected to the input end of the starting contactor, and the voltage transformer, an isolating switch and a second fuse are connected in series with each other and then connected in parallel between the first fuse and the starting contactor.

3. The integrated motor starter cabinet according to claim 2 is characterized in that: The isolating switch is logically interconnected with the load switch, and the on-off state of the isolating switch is controlled by the on-off state of the load switch.

4. The integrated motor starter cabinet according to claim 2, characterized in that: A running contactor is also connected in parallel at both ends of the reactor, and when the running contactor is closed, it is used to cut the reactor out of the control system.

5. The integrated motor starter cabinet according to claim 1, characterized in that: The reactive power compensation unit is connected in parallel between the reactor and the starting contactor, and comprises a third fuse connected in series and a compensation capacitor group, wherein the compensation capacitor group comprises at least three groups of capacitors connected in parallel.

6. The integrated motor starter cabinet according to claim 4, characterized in that: It also includes a lightning arrester, which is connected in parallel between the outgoing cable and the current transformer, and the lightning arrester is grounded through a bottom line.

7. The integrated motor starter cabinet according to claim 6, characterized in that: The cabinet is provided with a cable room and a component room. On one side of the cable room and the component room, a contactor room and a reactor room are arranged side by side from top to bottom. The component room includes a front room and a rear room. The reactive power compensation unit is arranged in the rear room. The load switch-fuse combination appliance, the voltage transformer, the second fuse, the isolating switch, the starting contactor, the current transformer and the lightning arrester are arranged in the front room. The incoming cable and the outgoing cable are arranged in the cable room, the running contactor is arranged in the contactor room, the reactor is arranged in the reactor room, and the reactor is installed at the bottom of the reactor room through a guide rail.

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