I'm new to FFT and harmonic distortions. I'm dealing with a power system where the phase currents are distorted.
Now I don't understand the concept of FFT and why the harmonics seen in FFT relate to the current waveforms. FFT shows how the current waveform changes in gain by frequency instead of time. How is it possible for something to generate a waveform across all frequencies by just looking at a waveform from one frequency? Could someone explain this in a more intuitive way instead of using mathematical language? Also, if harmonics are the changes in gain for other frequencies, why do I care about them if I'm running at a single constant frequency? How can these changes from other frequencies affect something from another frequency?
Also, is an RLC band-stop filter a good way of cleaning up the waveform by simply blocking out the frequency range where the harmonics are? How would you block out multiple frequency ranges since there's more than one bad harmonic?