Electromagnetic stirrers are key equipment in metal smelting, boasting a series of advantages such as non - contact pollution, uniform solution temperature, short smelting time, and precise control of chemical composition. As an important component of electromagnetic stirrers, the performance and characteristics of variable - frequency power supplies determine crucial indicators like the quality of metal smelting, energy - saving effect, and stirring quality index.
The "hero" behind an excellent variable - frequency power supply is precisely the high - performance general - purpose frequency converter that can be effectively modified. It can avoid the disadvantages of variable - frequency power supplies assembled by discrete components, such as low reliability, high failure rate, and difficulty in locating fault points. With its high stability and excellent energy - efficiency control, it has become the "secret weapon" for enterprises to save energy and reduce costs.
In July 2023, a steel group in Shandong completed the upgrading and renovation of multiple electromagnetic stirrers.
The project used all Hiconics' HC580-PLUS series low-voltage frequency converters for equipment renovation, creating good benefits for the enterprise.
Energy consumption reduced by 15 - 24%↓
Melting rate increased by 13 - 16%↑
Metal yield increased by 0.5 - 1%↑
Temperature difference between the upper and lower parts of the melt decreased from 90℃ to within 5℃↓
After the renovation, the equipment operates well. The renovation has comprehensively improved the automation level of the stirring process. The practice of workers using large rakes for stirring has completely become a thing of the past, greatly reducing the resulting metal pollution and the labor intensity of workers.
Case Site
Technical Requirements for Variable-Frequency Power Supplies
Frequency adjustment resolution: 0.1Hz (at least), 0.05Hz (optimal)
Voltage level: AC 380V
Allowable three-phase output current imbalance degree ≥ 15%
Low-frequency large inductive components
Profibus-DP communication protocol
Adjustable frequency: 0.5HZ - 10HZ, normal operating frequency: 1HZ - 8HZ
Electromagnetic Stirrer
The variable-frequency power supply is the key to energy efficiency.
Inductive electromagnetic stirrers are mainly composed of a variable-frequency power supply and an inductor. They drive the stirring and mixing of the metal solution by regularly changing the electromagnetic field at the bottom of the furnace. At the same time, the stirring direction and intensity of the molten metal can be effectively controlled by changing the direction and intensity of the moving magnetic field, which has significant advantages compared with traditional stirring methods.
As a key accessory for electromagnetic stirring, the variable-frequency power supply must operate stably and reliably for long periods under conditions of low voltage, low frequency, and high current. While providing necessary protection for the electromagnetic stirrer, it also needs to avoid the harmful effects of multiple high-power variable-frequency power supplies operating simultaneously on the power grid. These all pose higher requirements for the variable-frequency power supply.
"For the renovation of electromagnetic stirring power supplies,
HIC580-PLUS is the top choice."
There are two methods for manufacturing variable-frequency power supplies: assembling with discrete components and modifying general-purpose frequency converters. By modifying general-purpose frequency converters, it is possible to effectively avoid the disadvantages of the discrete-component assembly method, such as low reliability, high failure rate, and difficulty in locating fault points.
Compared with similar products, the Hiconics HIC580-PLUS series has excellent protection efficiency and energy-saving effects, making it a more suitable general-purpose frequency converter for modification into an electromagnetic stirring power supply. The 160kW - 450kW models of this series are standardly equipped with built-in DC reactors, which can protect the rectifier part of the frequency converter when the grid voltage fluctuates instantaneously. At the same time, it also suppresses the impact of some harmonic currents generated by rectification on the power grid, improves the current waveform input to the frequency converter, and enhances the frequency converter's ability to resist power grid voltage surges.
On - site Solution Implementation
1.Technical Requirements: The input voltage is 400V/50Hz, the output current is 400A, and the frequency ranges from 0 - 10Hz. A GGD cabinet is used to meet the communication and control requirements of steel enterprises.
2.Electrical Control: A SIEMENS S7 - 300PLC is used to control 8 dedicated variable - frequency power supply systems. Data is collected and control commands are issued through the Profibus - DP communication.
3.Control Functions: Stirring parameters (frequency and current) are automatically set according to the steel grade for casting and casting conditions. Manual online setting of stirring parameters is also available. The industrial computer is configured with configuration software to form a user - friendly Chinese human - machine interface, which can display process parameter values such as three - phase current, frequency, temperature and flow rate of the water system, and fault alarm records.
Product Advantages
Good Adaptability
It can be adapted to various motors such as synchronous motors, asynchronous motors, and permanent magnet synchronous motors.
Safe and Reliable
The protection function is highly efficient and reliable, with multiple protection functions such as power-on motor short-circuit detection, input and output phase loss protection, overcurrent protection, overvoltage protection, undervoltage protection, overtemperature protection, and overload protection.
Convenient Control
It supports multiple control modes such as VF control, open-loop vector control (SVC), and closed-loop vector control (FVC).
Strong Expandability
It supports 10 expansion cards, PG cards (including incremental type, rotary transformer, UVW), as well as communication expansion cards for buses such as MODBUS, PROFINET, PROFIBUS-DP, and CANopen.
Narrow Body Design
For models above 200kW, a narrow body design is adopted, with a width of less than 340mm, making it convenient for installation in narrow areas; the volume is reduced by 35% compared to the previous generation products, saving installation space.
Long-distance Communication
The liquid crystal control panel in the full power range supports long-distance communication up to 30m and has the function of parameter copying.
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