Ball mill is widely used in industries of mining, cement, building materials, metallurgy and chemical industry. During startup the ball mill motor usually has high inertia due to the heavy rotating drum with grinding media and material load .
When the motor is directly started across the line then it may create high starting current, voltage drop, strong mechanical shock and unnecessary stress on the gearbox, coupling and motor shaft. A ball mill soft starter can be a practical way to achieve a smoother and more reliable startup for fixed speed grinding systems.
1. Why Ball Mills Are Difficult to Start
Ball mills are not lightly loaded machines . When the motor starts up, it has to overcome the inertia of the drum, grinding balls and material in the mill. The mechanical impact can be transmitted to the entire drive train in case of a sudden start of the system.
Typical start-up problems are high inrush current, voltage fluctuation, coupling stress, gearbox impact, motor heating and protection trips.
In some plants, unstable starting also affects electrical equipment in the vicinity. Here is where the importance of controlled motor starting in ball mill applications is.
2. How a Soft Starter Helps Ball Mill Motors
When starting, a soft starter gradually increases the voltage to the motor. This method allows the ball mill motor to accelerate in a controlled fashion rather than applying full voltage immediately.
This helps to reduce starting current and mechanical shock for ball mill applications. It can also reduce the risk of sudden torque impact. And it can improve the startup stability.
A soft starter, unlike a VFD, does not provide continuous speed regulation during operation. However if the ball mill just needs smooth start and then run at fixed speed, soft starter for ball mill may be a cost-effective motor starting solution.
3. RENLE Soft Starter Solutions for Ball Mills
RENLE provides low voltage & medium voltage soft starter solutions for industrial motor starting applications. The product information lists soft starters for high inertia loads like fans, pumps, compressors, conveyors and ball mills.
Soft starter should be selected according to motor power, rated voltage, rated current, load condition, starting torque and site environment for ball mill motors.
Dust, vibration, heat and long working hours… these are the usual requirements at mining and cement plants. Therefore, before selection, cabinet protection, cooling design, bypass configuration and protection functions should be checked.
4. What Buyers Should Check Before Selection
When choosing a soft starter for ball mill, the buyer should be prepared with the motor nameplate and basic application information.
Important information: motor power, voltage, rated current, mill type, starting condition, starting frequency, starting time, working hours, ambient temperature and cabinet installation environment.
It is also necessary to check whether the ball mill starts with load or without load. When starting heavy loads, you may need a soft starter with a higher capacity and set the parameters carefully.
If you want a soft starter for ball mill, please provide us with your motor nameplate, ball mill working condition and site environment. RENLE engineers can assist with checking the correct soft starter configuration for your project.
