FFT harmonics analysis
Harmonics are integer multiples of the fundamental frequency (e.g. 50 Hz) and cause a distortion in voltage and current of the original waveform. Harmonic voltages and currents caused by non-sinusoidal loads can affect operation and lifetime of electrical equipment and devices.
Harmonic frequencies in motors and generators can lead to increased heating (iron & copper losses), can affect torque (pulsating or reduced torque), create mechanical oscillations and higher audible noise, can cause aging of shaft, insulation and mechanical parts and reduce the efficiency.
Current harmonics in transformers increase copper and stray flux losses. Voltage harmonics increase iron losses. The losses are directly proportional to the frequency and, therefore, higher frequency harmonic components are more important than lower frequency components. Harmonics can also cause vibrations and higher noise. The effects of other electrical equipment and devices are very similar and are mainly reduced efficiency and lifetime, increased heating, malfunction or even unpredictable behavior.