Squirrel cage motor is characterized by high speed and low torque, but it is usually started by soft starting device. This device enables the motor to start under no-load, and then connect the ultrafine mill when the rated speed is reached.Soft drive devices mainly include: hydraulic coupling, electromagnetic clutch, pneumatic clutch and liquid viscous clutch. There are two advantages of using hydraulic coupling.The first point is to provide the starting ability of the motor and improve the acceleration performance. The second point is that the motor can start without load, which reduces the starting current and shortens the duration of starting current.With such high economic performance, what is the price of small ultrafine mill? According to the fineness of crushed materials, the equipment configured for the mill is also different.