With global energy shortages, calls for energy conservation are getting louder and louder, and advanced energy-saving technologies are gradually becoming a trend. In many energy-saving enterprises, it is generally believed that ball mills are difficult to control. The amount of electricity consumed by electrical equipment is determined by its electromechanical characteristics, and subjective control is powerless. Obviously, this notion is wrong. Under the serious situation of electricity consumption across the country, bebort electric uses advanced frequency conversion energy-saving technical measures to minimize the energy consumption of ball mills, that is, to protect the environment and increase economic benefits by 5-10% for the enterprise.
Ball mill system problems
1. Ball mills generally adopt simple power frequency control, which is easy to cause excessive grinding of materials, requires a long grinding cycle, low grinding efficiency, and high power consumption per unit product.
2. Ball mills generally use star-delta or auto-coupling step-down to start, and the starting current is particularly large, which has a great impact on equipment and power grids
3. The production and maintenance of mechanical equipment are also large, and the amount of power loss is quite alarming. This will inevitably bring a lot of unnecessary troubles and a serious waste of resources to the manufacturer. With the development of the social economy and the expansion of the production scale of enterprises, the disadvantages of direct industrial control ball mills have been exposed. And seriously hindered the rapid development of various industrial enterprises. This prompts people to develop ball mills with a smooth start, high grinding efficiency, large output, and low energy consumption—special frequency converters for ball mills.
Energy-saving working principle of ball mill VFD
- System performance requirements
There are problems in the original working conditions and combined with the requirements of the production process, the ball mill system after transformation should meet the following requirements:
a. After the transformation, the equipment should have sufficient starting torque to meet the requirements of the large loading capacity of the ball mill, ensure the smooth operation of the motor under the frequency conversion operation state of the equipment, and ensure that the motor has constant power characteristics;
b. Use the frequency conversion speed regulation control system to transform the original ball mill drive system to meet the normal operation of the ball mill at low speed, ensure normal process control requirements, prolong the service life of the ball mill and the motor, and reduce maintenance.
- Frequency converter selection
Based on the above principles, canworld ball mill dedicated frequency converter is selected. This series of frequency converters have the following characteristics:
a. This series is low-speed rated torque output, with strong load capacity, and can reach 180% rated torque output at low speed.
It has a variety of torque boosts and V/F curves that can be set, a variety of acceleration and deceleration modes can be selected, built-in humanized PID function, and many parameters can be adjusted online.
b. With various perfect protection functions and fault diagnosis systems, with functions such as overvoltage, overcurrent, and stall protection, advanced technology, complete functions, easy to use, and can meet the needs of electrical energy saving and various production process requirements.
c. Various voltage levels, complete power specifications, and stable performance.
d. High-frequency accuracy, which can make the operation stable and meet the design requirements;
- Application effect
After installing the frequency conversion energy-saving control system on the ball mill, the following effects have been achieved:
a. After the transformation, the equipment can realize automatic control and mains power/power saving switching function and can overcome the rebound voltage caused by the large inertia of the ball mill, effectively ensuring the normal operation of the equipment.
b. Using the automatic voltage adjustment function of the frequency converter, it can maintain the highest motor efficiency under the condition that it has nothing to do with the load. Due to the elimination of shock during starting, the service life of mechanical parts such as the crankshaft, gearbox gear, and the belt is extended, and the maintenance cost is reduced.
c. The driving system of the ball mill has been improved by using frequency conversion speed regulation technology, which meets the characteristics of low-speed operation and large starting torque of the ball mill and realizes the continuous adjustment of the running speed of the ball mill. There is no inrush current when the motor starts, the starting torque is sufficient, and the protection function is perfect. The process control quality is guaranteed and the maintenance cost is saved.
d. After the ball mill uses frequency conversion speed regulation, the starting current is reduced, realizing a real soft start, and also receiving energy-saving effects. The starting current is greatly reduced, which will not cause an impact on the power grid and voltage drop of the power grid, and eliminate the tripping or failure of other electrical equipment caused by the start of the ball mill. Under the same power grid capacity, the number of installed machines can be increased.
e. Built-in PLC multi-speed automatic operation function, the frequency converter can be used to conveniently set the grinding time, grinding time, and automatic stop function, making the operation more intelligent and humanized.
f. The energy-saving effect of the frequency conversion speed regulation energy-saving system of the ball mill can generally reach about 12% to 15%.
