Frequency Converter "Brushless Cooling Fan" was a way to communicate the governor has brought a revolution. Over the last few years, with the continuous improvement of inverte technology and development. Frequency control performance increasingly perfect, has been widely used in AC Speed different fields. "Brushless Cooling Fan" for enterprises to bring considerable economic benefits, and promote the automation of industrial production process. Frequency control for AC induction motor speed control, its performance far exceeds any previous AC and DC speed control mode. And "Brushless Cooling Fan" simple structure, wide speed range, speed and high precision, easy installation, protection function, stable and reliable, energy-saving effect is remarkable, has become the latest trend of the AC motor speed control.