Current harmonics via FFT -- do peaks matter?

1. What do peaks in FFT represent?
2. Why do harmonics show up in FFT?
3. What are harmonics in FFT?
4. What causes harmonics in spectrum?

What do peaks in FFT represent?

FFTs of complex vibrations have multiple peaks- one for each frequency present in the vibration. Low frequency peaks are shown at the left end of the graph. The left-most peak represents the fundamental. Other peaks indicate overtones.

Why do harmonics show up in FFT?

Harmonics "happen" when your input to an FFT isn't a pure unmodulated sine wave. Any unexpected distortion in your input waveform generation (from being exactly identical to mix of sin(wt) + cos(wt)) can be the cause of harmonics appearing in an FFT result (above the noise floor and any windowing artifacts).

What are harmonics in FFT?

Chapter 11: Fourier Transform Pairs. Harmonics. If a signal is periodic with frequency f, the only frequencies composing the signal are integer multiples of f, i.e., f, 2f, 3f, 4f, etc. These frequencies are called harmonics.

What causes harmonics in spectrum?

Harmonics are the result of nonlinear loads that convert AC line voltage to DC. Harmonics flow into the electrical system because of nonlinear electronic switching devices, such as variable frequency drives (VFDs), computer power supplies and energy-efficient lighting.