60950

Posted by: lwathelet on 06/10/2010

I've made today an 60950 engineering evaluation in an approved organism. It uses a LNK304DN. My question is not on the certifications documents about the LNK304DN (see recent thread on that) but about this input filter capacitors. According to the certificator, he was requesting them to be X1 or X2 capacitors ! I think this request is completely impossible to meet as capacitors that meet safety certification has probably a maximum value of 56nF for ceramic or higher value for polycarbonate capacitors. In application designs presented here, you are mainly using aluminium Eletrolytics capacitors. As far as I know none of the aluminium Electrolytics capacitors are 60950 approved !
Does it mean my certificator must read again the 60950 specification or none of the PowerInt power supply application design can meet the 60950 requirements ?
I am a bit ironic, but here I am bit puzzled!!

Thanks in advance,

Luc

Comments

I think what you are talking about is for X capacitors which are connected between two phases, or between a phase and neutral. Our bulk DC capacitors are not connected directly to line or neutral. Please double check the requirements.

Hi,

No no, I'm talking the filter capacitors behind the rectifier ! According to the person I've met, they have to be X1 or X2 capacitor as high voltage from line is present there.

I think I've found the answer:
http://ewh.ieee.org/soc/pses/feature/0703emcpstc.html
http://www.iecee.org/ctl/osm_sheets/OSM-EE_decisions.html

And this is the document where it stands that capacitors behind the rectifier don't need to be approved !
http://www.iecee.org/ctl/osm_sheets/OSM-EE-PDF/xx_91-5-60950.doc

Could you confirm this is the correct justification ?

Regards,

Luc

I am glad you've found the answer. In my previous answer, I said only X capacitors need to meet the requirements you've mentioned because "X capacitors are connected between two phases, or between a phase and neutral". However, the "bulk DC capacitors are not connected directly to line or neutral", so those requirements for X capacitors don't apply to the bulk capacitors.