What is the function of a non-linear load like VFDs?

A non-linear load, such as Variable Frequency Drives (VFDs), is characterized by its ability to distort the current waveform as it draws power from the electrical system. This distortion occurs because these devices do not draw current uniformly throughout the entire AC waveform, which results in a non-sinusoidal current. Essentially, VFDs control motor speed and torque by varying the frequency and voltage supplied to the electric motor, but while doing so, they also introduce harmonics into the system.

The presence of harmonics means that the current waveform deviates from the ideal sine wave, which can lead to several issues such as overheating in electrical equipment, increased losses in transformers and generators, and interference with communication lines. Understanding this effect is crucial for electrical contractors and engineers when designing and implementing systems that include non-linear loads, as they need to take measures to mitigate potential problems caused by harmonics.

In contrast, continuous current, voltage regulation, and power factor improvement are functions typically associated with linear loads or specific corrective devices and are not part of the inherent characteristics of non-linear devices like VFDs.