Hello,
I am tested various emi filter on the market. And decided to design my own with trial and error method and get very good results better than commercial units.
You can find the test results unfiltered ac line vs my design filtered in the attached picture.
With my design, i got better noise figure than any commercial unit i tested and i tested more than 30 unit.
I am not an filter expert i just make lots lots of trial to find a good solution.
But after all these effort none of mine or commercial units not able to filter under 10Khz noise.
I am glad if any one know any solution or any comments.
I am tested various emi filter on the market. And decided to design my own with trial and error method and get very good results better than commercial units.
You can find the test results unfiltered ac line vs my design filtered in the attached picture.
With my design, i got better noise figure than any commercial unit i tested and i tested more than 30 unit.
I am not an filter expert i just make lots lots of trial to find a good solution.
But after all these effort none of mine or commercial units not able to filter under 10Khz noise.
I am glad if any one know any solution or any comments.
Attachments
Looks interesting, but I can't tell whether you're keeping line noise out, or equipment noise in.
Are you keeping the design / schematic a secret?😉
As to the low frequency bump, your magnetics (if you have some) may be saturating.
Cheers
Are you keeping the design / schematic a secret?😉
As to the low frequency bump, your magnetics (if you have some) may be saturating.
Cheers
Interesting results, again would be good to see a schematic, I would have thought filtering below 10kHz would be easier than above.
I am not surprised a typical EMI filter is designed to remove/lower HF interference through a combination of inductance and capacitance by lowering the impedance path to earth.
If you can design a HF filter then use the same formula to design low frequency filter there is a standard formula for it .
Or are you using a "virtual helper " ?-- I am talking old school mental calculations .
If you can design a HF filter then use the same formula to design low frequency filter there is a standard formula for it .
Or are you using a "virtual helper " ?-- I am talking old school mental calculations .
I already did many trials but to get to filter such low frequencies would require increasing so-called leakage current to the levels that would a) require that the filter is permanently grounde b) can not pass CE certification rules and cause earth leakage breaker trigers.
Have you looked at active filters where the low frequency noise is not passed directly to earth as in a standard passive filter ?
I used to do EMC testing.
It was quite often found that trial and error worked very well in some circumstances.
Try 2u2 across mains with 1mH inductors in series then 2u2 across output.
Always worked well for me.
It was quite often found that trial and error worked very well in some circumstances.
Try 2u2 across mains with 1mH inductors in series then 2u2 across output.
Always worked well for me.
Active filters ( in mains supplies ) inject , in the opposite direction ,the harmonics drawn by the load ,so that the line current stays sinusoidal .
While this is industrial power supply ( utility company ) related some of it could apply to your situation with variations.
Noise/distortion in a sine wave supply upsets the purity of the sine wave supplied.
I am not talking audio situations here just the power supply.
While this is industrial power supply ( utility company ) related some of it could apply to your situation with variations.
Noise/distortion in a sine wave supply upsets the purity of the sine wave supplied.
I am not talking audio situations here just the power supply.