The inverter control cabinet (also known as the inverter cabinet and the inverter starting cabinet) is composed of the built-in inverter and the peripheral control, protection, display and other electrical components and cabinets, and is an AC drag device and energy-saving device for frequency conversion speed control of three-phase AC motors (including fans, pumps, etc.). The following is a detailed introduction to the inverter control cabinet, including its technical parameters:
First, the main components
The main components of the inverter control cabinet include inverters, PLC (programmable logic controllers), digital-to-analog conversion modules, temperature sensors, temperature modules and other devices.
Second, the main functions
Power switching and protection: The inverter cabinet is equipped with a low-voltage molded case circuit breaker connected to the incoming power supply, which can not only complete the connection and disconnection circuit, but also protect the short circuit and overload of the circuit and the inverter, and cut off the power supply during maintenance.
Start and stop control: Frequency conversion start and frequency conversion stop buttons are set on the panel of the frequency conversion cabinet for the operation control of the frequency conversion device, which is convenient for on-site operation.
Frequency (speed) adjustment: A frequency adjustment potentiometer is set on the panel of the frequency conversion cabinet, which can easily adjust the output frequency of the frequency converter manually to control the motor speed.
Standby power frequency switching: Users can choose a frequency conversion cabinet with standby power frequency switching. When the inverter fails, the motor is switched to the power supply through the automatic control loop (this mode can be selected manual/automatic, and the power frequency starting device is more than 15KW with a soft starter).
A variety of control functions: according to the working conditions of the system, a variety of control buttons and indicators are set on the panel of the inverter cabinet, such as forward rotation, reverse, motor speed increase, motor deceleration, jog forward rotation, jog reversal, manual/automatic, emergency stop, frequency conversion/power frequency, PLC control, touch screen, etc.
Installation of peripheral equipment: AC input reactor, output reactor, DC reactor and EMI filter, braking unit, braking resistor, contactor, intermediate relay, thermal relay, programmable controller (PLC), programmable operation terminal (GOT), watt-hour meter, cooling fan, etc. can be installed in the frequency conversion cabinet according to the needs of working conditions.
Safety protection: The inverter is installed in the inverter cabinet, which can reduce the risk of environmental pollution and electric shock, and play a better protective role. At the same time, the inverter cabinet adopts a closed cabinet structure, and the protection level is generally IP20, IP21, IP30, etc.
20, IP21, IP30, etc.
Third, the field of application
The inverter control cabinet can be widely used in metallurgy, chemical industry, petroleum, water supply, mining, building materials, motor industry and other pumps, fans, air compressors, rolling mills, injection molding machines, belt conveyors and other medium-voltage motor equipment.
4. Typical applications
Constant pressure water supply: By controlling the output flow of the water pump, the constant pressure operation of the water supply system is realized.
Air compressor: Through frequency conversion speed regulation technology, the operation of the air compressor is controlled to improve energy efficiency.
Fan and water pump: Frequency conversion speed control of fans and pumps to achieve energy saving and consumption reduction.
5. Technical parameters (examples)
The following technical parameters are examples, the actual product may be different, please refer to the specific product manual:
Control motor power: According to different models, the power range of control motor may include 0.37-15KW, 15-90KW, 15-160KW, 0.18-250KW, etc.
Control voltage: generally 380V.
Control the number of pumps: Depending on the model, the number of pumps that can be controlled may include 1-4, 1-5, etc.
Pressure control accuracy: For the automatic frequency conversion speed control cabinet, the pressure control accuracy may reach 0.02MPa or -0.02MPa.
Power supply: mains, self-provided power grid, diesel generator set; Three-phase AC 380V (-10%, +15%), 50HZ.
Applicable motor: general squirrel cage asynchronous motor.
Starting frequency: It can be started frequently, and it is recommended not to exceed 20 times per hour.
Degree of protection: IP41 or IP20; The altitude shall not exceed 2,000 meters (more than 2,000 meters shall be used in a reduced capacity); The ambient temperature is between -25°C~+40°C; The relative humidity does not exceed 95%, and there is no condensation; The vibration is less than 0.5G.
6. Setup Guide
When setting up the inverter control cabinet, it is necessary to understand some basic parameters of the inverter and make reasonable parameter configurations. Here are some setup guidelines:
Confirm the power matching: Ensure that the power supply voltage and frequency connected to the frequency conversion control cabinet match the rated voltage and frequency of the equipment.
Check the connection of equipment: check whether the connection of inverters, motors, sensors and other equipment is firm, whether the cable insulation is intact, and whether the wiring is correct.
Set motor parameters: Enter the rated power, rated voltage, rated current, and rated speed of the motor.
Frequency setting: Set the high frequency and low frequency according to the actual demand. Normally, the high frequency is set to the rated frequency of the motor, and the low frequency can be set to 0Hz.
**Acceleration/deceleration timeWhen setting the acceleration/deceleration time of the inverter control cabinet, it needs to be set according to the load characteristics, usually between 5~30 seconds. Reasonable acceleration and deceleration time helps to reduce the shock when the motor starts and stops, and prolongs the service life of the motor.
Protection parameter settings
Set overload protection, overvoltage protection, undervoltage protection, etc., to ensure that the equipment can automatically shut down in abnormal situations, so as to protect the motor and inverter from damage.
According to the rated current of the motor and the actual load, the overload protection parameters are reasonably set. When the motor load exceeds the set threshold, the inverter should take protective measures in time, such as reducing the output frequency or cutting off the power supply.
Mode of operation selection
Choose the appropriate operating mode according to the actual needs, such as constant speed, variable speed or PID control.
Communication parameter settings
If you need to communicate with the host computer or other devices, you need to set the corresponding communication parameters, such as baud rate, data bits, etc.
7. Debugging and testing
After the parameter setting is completed, a test run is required to verify the correctness of the setting. Observe the operating status of the motor to ensure that it runs smoothly within the set frequency range. During the test, it is necessary to closely observe the operating status of the motor and the pressure change of the system, and find and deal with abnormal situations in time. You can manually operate the operation stop button of the inverter panel, observe the motor operation stop process and the display window of the inverter, and check whether there is any abnormality.
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