Harmonics
Harmonics
(OP)
Hey, was wondering if anyone would be able to give me a bit of guidance on the analysis of THD%, having trouble discerning between which is causing problems and what isnt
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RE: Harmonics
Rafiq Bulsara
http://www.srengineersct.com
RE: Harmonics
Measuring the current THD will indicate what is causing the distortion.
Bill
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"Why not the best?"
Jimmy Carter
RE: Harmonics
What problems are being experienced, or imagined?
What types of equipment are you concerned with?
Have you made measurements or are you just trying to learn about harmonics?
RE: Harmonics
RE: Harmonics
RE: Harmonics
"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla
RE: Harmonics
The values of harmonic contribution will be available from each equipment vendor. Some safe assumptions can also be made in case of missing data.
RE: Harmonics
RE: Harmonics
RE: Harmonics
Is the hum the normal 120Hz (Often called 60 Hz hum) that we are all familiar with? If harmonics are causing the hum and vibration it will probably be at twice the harmonic frequency.
Check your neutral for any loose mounts or loose ferrous metal near the neutral. Third harmonic currents flow in the neutral when they can. Unbalanced currents flow in the neutral. Investigate the possibility of single phase or unbalanced loads, and neutral currents in general when the plant is operating.
If you always have humming, that increases in volume when the plant is running, look for loose hardware. If you only have humming when certain equipment is running, check the neutral.
The first rule of trouble shooting is to properly define your trouble.
I believe that your trouble is humming and vibration.
To assume that your trouble is harmonics may cause you no end of grief if the problem is not caused by harmonics.
If you are still unable to monitor working currents, you may physically check the neutral supports and the surrounding metal for looseness, and inquire about line to neutral loads.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Harmonics