non-order harmonics
non-order harmonics
(OP)
I searched about non-order harmonics but couldnt be able to find anything, if there is such a concept, why do these non-order harmonics occur?
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
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RE: non-order harmonics
RE: non-order harmonics
If a frequency is not a multiple of the fundamental frequency it is not a harmonic.
However, a square wave contains components of all frequencies and may induce ringing at a non harmonic frequency.
Bill
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"Why not the best?"
Jimmy Carter
RE: non-order harmonics
I've heard the term "sub-fundamental" harmonics, but that doesn't sit well with the classic definition. Nor are fractional harmonics. If somebody is "finding" these, there is something somebody's missing in the analysis.
old field guy
RE: non-order harmonics
Such is encountered in vibration analysis. I may have present in my spectrum:
1xTS, 2xTS, 3xTS... (where TS is turning speed)
1*BPFO, 2*BPFO, 3*BPFO...(where BPFO is Ball Pass Frequency Outer race... in generall not an exact multiple of turning speed).
I agree with the others, clarification of the original question is in order (pun intended).
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RE: non-order harmonics
"signal with two fundamental frequencies"
is not stricly correct. I should have said
"signal which includes the sum of two periodic signals that have different fundamental frequencies"
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RE: non-order harmonics
saltukhan needs to characterize the spectrum of of his signal a bit better. 'Non-harmonic' could mean some signal with distinct peaks in the frequency domain or broadband noise. The former are usually generated by some mechanism with a distinct period or resonant frequency, such as your shaft speed and bearing example. The latter are generated by aperiodic mechanisms (corona discharge comes to mind as one example in the T&D biz).
RE: non-order harmonics
Neil
RE: non-order harmonics
Interharmonic components are caused primarily by two
sources:
• Variations of the amplitude and/or phase angle of the
fundamental component and/or of the harmonic
components,for example, inverter drives
• Power electronics circuits with switching frequencies
not synchronized to the power frequency, for
example, a.c./d.c. supplies and power factor
correctors
RE: non-order harmonics
Direct, inverse and homopolar sequences are not sine anymore, they are a sum of distorded harmonic currents.
Maybe this could explain these interhamonics. Perfectly balanced systems do not exist.