The SINCR C500 560kw high-power inverter has been successfully applied to ball mills.

1. User situation

Qinghai City ** Mining Co., Ltd. is a research and development integrated resource company controlled by Qinghai Non-ferrous Geological Survey Bureau. A set of ball mill systems is added for production needs. After research, the company's leaders decided to use SINCR 560KW inverter to modify the ball mill in order to reduce production costs and improve the operating efficiency of the ball mill system. The picture below is a live photo

2. Product requirements:

For a long time, the ball grinding machine has been widely used in the mining grinding process. Generally, it is started by a hydraulic coupler. The large starting current has a large impact on the equipment and the power grid. At the same time, the power frequency is easy to cause excessive grinding of the material and the grinding cycle is long. The grinding efficiency is low, and the power consumption per unit product is large, which prompts people to develop a ball mill control system with smooth starting, high grinding efficiency, large output and low energy consumption, and the frequency conversion speed control technology has remarkable speed regulation performance and remarkable The power saving effect, improving the operating conditions of the equipment, improving the safety and reliability of the system, and prolonging the service life of the equipment have become a development direction of modern electric drive technology, but in the most important equipment ball mill in the traditional grinding process. There are still few control systems using variable frequency speed control.

3. Comparison of the common control methods of ball mill and the frequency control method

At present, the ball mill is generally used to start the fluid coupling, which exists:

(1) The starting current is large, which has a great impact on the equipment and the power grid;

(2) The stability of equipment operation is poor, and the maintenance and power consumption are huge;

(3) The required grinding cycle is long, the grinding efficiency is low, the power consumption per unit product is large, and the transition grinding of materials is easily caused, which increases the maintenance cost of the manufacturer and causes serious waste of resources.

After using the frequency conversion speed regulation, the ball mill has the following advantages:

(1) The soft start of the system is realized, the starting current is greatly reduced, which is 3 to 5 times smaller than the previous power frequency control, eliminating the impact at the start, prolonging the service life of the mechanical components and reducing the maintenance of the equipment and Maintenance costs;

(2) Reduce the impact on the power grid and peripheral equipment, use the frequency conversion vector speed control technology to drag, meet the characteristics of the ball mill low speed operation, large starting torque, and effectively ensure the control technology of the system;

(3) The superior stepless shifting function changes the past fixed speed grinding method, greatly optimizing the grinding efficiency and the uniformity of the grinding object;

(4) The system has perfect protection functions such as over temperature, phase loss, short circuit, over voltage and over current. The Chinese touch screen can intuitively and accurately view the internal data of the device.

4. Ball mill inverter debugging use precautions

The ball mill frequency converter needs to pay attention to the following when debugging:

(1) Because the load nature of the ball mill is constant torque, the mechanical characteristics are hard and the dynamic characteristics are high, so the vector control function of the inverter should be selected; although the V/F control has the torque boost function at low speed, Insufficient lifting, the motor torque may not meet the needs of starting or low-speed steady-speed operation. If the lifting is too large, it may over-current due to saturation of the magnetic circuit.

(2) The ball mill has more dust on site, so there should be enough space around the inverter to ensure good ventilation. The site should be installed in a well-ventilated place away from heat sources and dust.

(3) After the commissioning is put into operation for a period of time, the main parts such as the main circuit wiring should be inspected and dusted regularly to avoid the excessive accumulation of dust and affect the normal operation of the inverter.

5. Conclusion

Since the ball mill frequency converter of Qinghai City** Mining Co., Ltd. was put into operation in March 2018, it has been operating normally. The transformation achieved the intended purpose. After calculation by the mine energy conservation center, the power consumption of the inverter reached 25.2%, and the energy saving effect was obvious. The frequency converter can accurately adjust the motor speed according to the crushing condition of the raw materials in the mill, improve the operating efficiency of the ball mill, and achieve good economic and social benefits. With the increasing emphasis on energy conservation and emission reduction in China's “13th Five-Year Plan”, SINCR frequency converters are used for high-power, high-energy-consuming equipment with significant power-saving effects, stable performance and high reliability, and have important promotion significance.