因而交流电动机的直接调速方式主要有变极调速(调整P)、转子串电阻调速或串级调速或内反馈电机(调整s)和变频调速(调整f)等。
Therefore, the direct speed control mode of AC motor mainly includes variable pole speed regulation (P), rotor series resistance speed control or cascade speed regulation or internal feedback motor (adjusted s) and frequency conversion speed regulation (adjusted f).
而我们现在运用最广泛的就是变频调速，由转速n与频率f成正比，只要改变频率f即可改变电动机的转速，当频率f在0～50Hz的范围内变化时，电动机转速调节范围非常宽。变频器就是通过改变电动机电源频率实现速度调节的，是一种理想的高效率、高性能的调速手段。
And we are now the most widely used is the frequency conversion, speed and frequency of F by N is proportional to, as long as the change frequency of F can change the speed of the motor, when the frequency of F in the 0 ~ 50Hz range when the motor speed adjustment range is very wide. Frequency converter is to change the motor power frequency to achieve speed regulation, is an ideal high efficiency, high performance speed control means.
