They are electronic devices that convert the voltage of the alternating current into a constant current of constant amplitude and frequency, and finally converts the latter into a voltage of variable timing belt pulley sizes amplitude and frequency (AC). These devices completely control the electric motor speed from zero to the maximum rated frequency or higher. These devices are used in induction motors, replacing the rudimentary mechanical speed variation systems such as pulleys, electromagnetic drives and hydraulic drives, as well as costly DC motors with the asynchronous motor and inverter assembly, which is cheaper, easier maintenance and easy replacement.
Frequency drives control the speed and speed of the electric motor to meet demand for lossless processes, leading to considerable energy savings. They have great use in the machinery industry and processes in general. There are inverters that can generate an alternating voltage (AC) of up to 7200Hz to power special motors. The drives have the agility to act as protection devices for the various electrical network problems that can occur, such as imbalance of voltages between phases, phase failure, overvoltages, undervoltages, overload, voltage drop, etc.