磨机是水泥厂、矿山、电厂等粉磨系统中的关键设备，由于其自身转动惯量大，为恒转矩性负载，因此在８０年代以前其起动问题一直没有解决好。液体变阻器的应用大大地改善了磨机等大型设备的起动性能，其主要特点是在被控大、中型电动机的转子回路中串入了一液体电阻，且此电阻 Mill is the key equipment in cement mill, mine, power plant and other grinding systems. Because of its large moment of inertia and constant torque load, the starting problem until 1980s has not been solved. The application of liquid rheostat has greatly improved the start-up performance of large-scale equipment such as mills. Its main feature is the inclusion of a liquid resistor in the rotor circuit of a controlled large and medium-sized motor, and the resistance