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    Conducted emissions: Noise current limit for house hold appliances.

    Hi all,

    Please what's the figure for the conducted emissions noise current limit at 100kHz for household appliances?

    I'm making an SMPS for home appliance.
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    It depends on where you live. There is no global standard.



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    Re: Conducted emissions: Noise current limit for house hold appliances.

    I'm making it for homes in places where there are no standards. Even if I do not limit EMI, there would be no issues but I just can't afford to pollute the whole place. Products around the locality don't limit emissions but I'll be happier limiting mine. If not for anything, immunity is worth it.

    I'll be fine with any renowned standard.

    Thanks in anticipation.
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    CISPR 22 is the generally applicable standard for frequencies above 150 kHz. There are some attempts to extend the limit values down to 9 kHz with rising magnitude, but no agreed standard yet. CISPR 14 has specific limit values for induction cookers below 150 kHz.



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    Re: Conducted emissions: Noise current limit for house hold appliances.

    CISPR 22 is the generally applicable standard for frequencies above 150 kHz. There are some attempts to extend the limit values down to 9 kHz with rising magnitude, but no agreed standard yet. CISPR 14 has specific limit values for induction cookers below 150 kHz.
    I guess it doesn't have a plot with frequencies traceable to limit values.

    In that case, how do I go about it? I'm designing for a control system that is supposed to run 24/7.
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    Akinamo here is one conducted scan from UK...for a lighting product prototype (offline 60w flyback smps)


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    Re: Conducted emissions: Noise current limit for house hold appliances.

    I didn't look for CISPR 15, because it's not strictly applicable here, but it has the first general conducted emission limit values downto 9 kHz. Thanks for mentioning.



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    Re: Conducted emissions: Noise current limit for house hold appliances.

    I believe CISPR 15 is for lighting. Will it be suitable for my application? I'm designing for a control system that is supposed to run a motor. Maybe I can use its plot?
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    If you think there is something I do not understand with this question, you could explain further please.
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    It seems this post has come to an end. Please what's the conclusion here? Somebody should help explain to me. Thanks.
    -------------
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    You asked for “the figure for the conducted emissions” and people made many suggestions. Since your device is going to a place with no requirements, there is NO FIGURE. The ‘conclusion’ is :You can do whatever you want.

    Again, THERE IS NO REQUIREMENT (you said so), but you are asking people to give you one.


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    Re: Conducted emissions: Noise current limit for house hold appliances.

    Even if there are no valid EMI regulations in your place (sure about?), people might expect compliance with common international standards like CISPR 22 or CISPR 14. As already mentioned, they presently don't cover the range below 150 kHz. If you are seeking for reasonable 100 kHz limit values, why not referring to CISPR 15?


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    Re: Conducted emissions: Noise current limit for house hold appliances.

    Yes, there's no requirement as I said. The point here is that where there is no requirement, there is so much noise.

    The standards are not just made for the sake of formality. There's a definite purpose. Because there is so much noise around so I believe that if I meet the appropriate requirement for the category of device as I listed in Post #1, I'd benefit from the immunity that comes with it.

    Treez mentioned CISPR 15 which like FvM also pointed out, is for lighting and not quite applicable to my device. FvM mentioned CISPR 22 but the frequency it covers is 150kHz and above. Mine is 100kHz.

    I know that I can do what I want if I want to, but I don't want to. I believe there are members here that design this sort of devices, so I'm asking for what is used.

    Please do not consider where I am designing for. Just tell me what standard you would use where you are. Please.
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    do a flyback design on PI Expert software on power integrations website......match it to your spec...then copy the emc filter they give you.

    Or copy this one if its like yours

    https://www.st.com/content/ccc/resou...CD00252755.pdf
    Last edited by treez; 20th April 2019 at 22:40.



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    Re: Conducted emissions: Noise current limit for house hold appliances.

    Okay, gotten.

    Thanks for all your responses. I value them a lot.

    I'll go with CISPR 15. I am aware of military standards with limits specified in dBuA. I have to do a little research on how to use dBuV which I'll do. However, if you can give me a pointer, then I'll so much appreciate it.
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    Re: Conducted emissions: Noise current limit for house hold appliances.

    I don't agree with your conclusions. Particularly they don't seem to be substantiated by detailed reading. Why do you think the CISPR 15 limit values can't be applied for your device class? You'll notice that the requirements for conducted emissions >150 kHz are effectively identical across the different standards. Extending the limit values below 150 kHz is somehow arbitrary, the CISPR 15 curve is at least a reasonable choice.

    If you go the comfortable way, apply CISPR 14, no limit value for conducted emissions at 100 kHz.

    - - - Updated - - -

    If your problem is relation of voltage and current emissions, that's trivial, just apply standard LISN impedance.



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    Re: Conducted emissions: Noise current limit for house hold appliances.

    1 dBuV = 20LOG(10) [V/1uV]

    ...so you can work out the "V" from this...thats the Volts that is 1dBuV.



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    Re: Conducted emissions: Noise current limit for house hold appliances.

    Theoretically - you can do what you like below about 145kHz, however most countries have a clause in their statutes about not interfering with other equipment - so the emissions at the lower frequencies must be reasonable. Germany used to have strict TUV standards down to about 8kHz - but then had to harmonise with the rest of the EU. In the region 50Hz to 20kHz if you are over 75W continuous you must comply with harmonics spec in EU countries.

    - - - Updated - - -

    dBuV is simply the amount of uV ( above 1uV ) in dB, so 120uV = 20 log 120 = 41.6dBuV, 1uv of noise is 0dBuV on this scale, 1mV = 60dBuV.


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