ABSTRACT
This chapter discusses a method which applies AC variable frequency to control the rotatory screen motor to start with variable frequency, and carries out the variable speed operation with the sine rule. The conventional rotatory screen usually adopts constant speed uniform rotation or two-speed uniform rotation. The motor speed is adjusted in this design based on the water level before and after the rotatory screen in the method of closed-loop. The rotational speed of the rotatory screen changes according to the sine rule. In the way the dirt on the rotatory screen could lose under the work of inertia, and then the rinse can have a better cleaning of the dirt. Rotatory screen system is an important component device on the industrial cooling water system. The life of the rotatory screen motor is extended; the system efficiency is improved; and the energy is saved with the variable speed operation mode.
