Traditionally, AC motor is usually used as fan impeller driving device that have many advantages of EC technology are becoming more and more difficult to ignore. Over KW three-phase AC asynchronous motor has satisfactory efficiency in full loading operation, but the efficiency of single-phase or less than KW three-phase motor cannot meet the requirements. AC motors also need to use frequency converters to control speed, which will cause power loss, and additional filtering is required to protect sensitive motor bearings. Using frequency converter to drive asynchronous motor with partial load often produces noise, which makes the motor hum.
There are three main customer demands for fans in the field of ventilation: Energy efficiency, adaptive self-regulation control ability
according to load changes, and flexibility to meet the variety of application needs of customers.