Harmonics are a recurring distortion
of the waveform that can be caused by various devices including
variable frequency drives, non-linear power supplies and electronic
ballasts. Certain types of power conditioners like ferroresonant or
constant voltage (CVT) transformers can add significant harmonic
distortion to the waveform. Waveform distortion can also be an
issue with uninterruptible power supplies (UPS) and other
inverter-based power conditioners. The UPS does not actually add
distortion, but because the UPS digitally synthesizes a waveform, that
waveform may be square or jagged rather than a smooth sine wave. Symptoms of harmonic distortion include overheating and equipment operational problems |