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What happen if I use EMI filter at more then specified current

Dinesh Dangi

May 10, 2018
4
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May 10, 2018
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I want to use Gaia EMI filter. my load requirement is 1.7 A continuous and 3.5A Max. Voltage is 28 V. Because of the max current I have to use FGDS-10A-50V(load current can go up to 10A) but this size to too much for me. So my question is if I use FGDS-2A-50V(load current 2A) filter and when in some case my current will go 3.5 A what will happen with the filter? will it stop working and when my load will be again less the 2 A it will start filtering..? Or once the current will go high my 2 A filter will not be workable again?
 

hevans1944

Hop - AC8NS
Jun 21, 2012
4,878
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Jun 21, 2012
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4,878
Well, if you have sufficient karma, it is possible to ignore the engineering specifications and operate the filter at any current you so desire. The only reason there are 2A and 10A continuous current models is to guarantee operation at those currents. There are coils (inductors) inside the EMI filter whose wire resistance dissipates power, said power increasing as the square of the current. Exceed the manufacturer's specifications for maximum current at your own risk.

It is also possible that higher than specified current may cause saturation of the magnetic core (usually a toroid made of a ferrite material) of the inductor, which will lower its effective inductance and reduce the effectiveness of the EMI filtering.

Good engineering practice does not push the envelope of device performance if reliability and long service life are important considerations, which they should be. You are already pushing the performance envelope by using a 2A rated component with a 1.7A continuous load. But if it is your desire to cut corners for maximum profit, go ahead and do so. You might even catch up with other Asian vendors who have been doing the same for years now. The device you specified is MIL-SPEC qualified. They don't hand those out like gum drops, but you generally get what you pay for from reliable manufacturers: quality parts, conservative design, and high reliability as long as you stay within the design envelope.
 

WHONOES

May 20, 2017
1,217
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May 20, 2017
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1,217
Not advisable. If you are trying to make something that is compliant with a particular standard then it will probably fail because the filter is not working properly.
As Hevans1944 said, you should always de-rate such devices for reliability and correct functioning.
 
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