我们从最直观的外部线路上入手。首先，变频器仅通过连接电机三根大线：R，S，T便可以实现对电机的无级调速了。先挖下变频调速的原理吧，以三相异步电机为例，三相异步电机里的定子绕组是三相对称的，在定子绕组里再通入三相对称的电流，于是在转子周围会产生一个旋转的磁场，旋转磁场再切割转子导体使转子绕组产生感应电流，电流会导致转子绕组在旋转磁场受力，从而驱动转子旋转。并且输出频率决定旋转磁场快慢，从而实现对转子调速，有一道公式同步转速n=60f/p就是讲这个的，当然级数便指这些定子绕组的数量了。平时我们在变频器的监控菜单里发现变频器的电压跟频率是成比例的变大或变小的，因为在额定的工作频率下，若电压一定的情况下只降低频率，会导致磁通过大，甚至会烧毁电机，反之，若磁通不够，会直接造成电机输出转矩不足。 We start with the most intuitive external circuit. First, the inverter simply connects to the motor's three large lines: R, S, and T can be used to speed the speed of the motor. Dig under the principle of frequency control of motor speed, taking three-phase asynchronous motor as an example, the stator winding in three-phase asynchronous motor is the three-phase symmetrical, recanalization in stator winding into the three-phase symmetrical current, so will produce a rotating magnetic field around the rotor, a rotating magnetic field cutting rotor conductors again make the rotor winding induced current, the current will cause the rotor winding in a rotating magnetic field force, so as to drive the rotor rotation. Determine how quickly a rotating magnetic field and the output frequency, so as to realize the rotor speed, there is a formula synchronous speed n = 60 f/p is telling this, of course series is refers to the number of the stator winding. We found in the inverter monitoring menu at ordinary times the voltage to frequency converter is proportional to the larger or smaller, because under the rated working frequency, if certain cases only the lower frequency voltage, can lead to magnetic by large, and even burning motor, on the other hand, if the flux is not enough, will directly cause the motor output torque.