水泵、风机等机械设备的动力通常用鼠笼型感应异步电动机,因为这种电机具有价格低廉运行可靠等特点,但其转速取决于电源的频率和电动机的设计参数——极对数,这就引出了感应异步电动机的调速问题。水泵在工作期间经常需要改变转速来达到调节出水量和压力、机械上常采用离合器、变 Pumps, fans and other mechanical equipment usually use squirrel cage induction motor, because the motor has the characteristics of low cost and reliable operation, but the speed depends on the power frequency and motor design parameters - the number of pairs, which The induction induction motor speed control problems. Pumps often need to change the speed during work to achieve the regulation of water and pressure, the machinery often used clutch, variable