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How can I solve third harmonics?

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#1 Diana


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Posted 06 February 2004 - 12:41 PM

How can I lower a third hamanic, and how much can I lower it?
If in a houes a 3% is normal and I have a 5%, How can I lower these hamonic or lower them, what kind of solution I can apply and how I jook it up?
How can I solve or lower this problem?

#2 marke


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Posted 22 February 2004 - 12:27 AM

Hello Diana

Welcome to the forum.
Harmonics are a problem to get rid of.
The best solution is to isolate the source of the harmonics and see if there is a solution for it.
A common source of harmonics is electronic rectifier circuits. Switch mode power supplies are a common source of harmonics.
It is possible to design and build switchmode supplies that do not generate the same level of harmonics by using a "power factor" circuit in the design. This is an active circuit using a switching device (i.e. a FET) and inductor to ensure that current flows all the time. Unfortunately, this is not easily retrofitted to and existing circuit.

There are really two major options

  • Passive Filter Circuit
  • Active Filter Circuit

      These can be connected in series with the source of the harmonics and will reduce the harmonic current content. Unfortunately, these are expensive options and will only be used where absolutely necessary.
      The big question to ask is: are the harmonics really causing a problem and how much is it worth to fix the problem.

      Best regards,

#3 leeeetao


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Posted 07 September 2004 - 06:58 AM

use or products.
we are experts in this line. We specializes in reactive power compensation and harmonic filtering.
we have provide more than 300 sets of our harmonic filter device all over our country.

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