Frequency inverters, also called frequency converters, are electronic devices that convert the voltage of the alternating sinusoidal network into direct voltage and finally convert the latter into a voltage of variable amplitude and frequency. As seen earlier the speed of rotation of an induction electric motor, 8078-j will depend on the frequency of the mains. The higher the frequency, the higher the rotation and vice versa. Thus, when an induction motor is fed by a frequency inverter, we can easily control the speed of the motor shaft by means of the frequency variation conferred by the inverter.
The frequency of operation of an inverter will generally be between 0.5 and 400Hz depending on the model and the brand. Frequency inverters have an input connected to the common power supply network, which can be single-phase or three-phase, and an output that is concentrated to the device to be fed, in this case a three-phase induction motor (MIT). Frequency inverters not only control the speed of three-phase AC motors, but also control other parameters essential to the electric motor, one of which is torque control.