Paper Capacitors

Discussion in 'General Electronics Chat' started by mlkcampion, Dec 17, 2011.

  1. mlkcampion

    Thread Starter Active Member

    Nov 16, 2006
    59
    0
    Hi,
    I need to replace a paper capcitor on a Temperature controller. The part number is PME261JB. I have found some similar looking capcitors on Farnell, same value etc. However the part number is PME271Y522M. The parts appear very similar to me.

    What is the difference between the PME261J and the PME271Y?

    Can i use the PME271Y instead of the PME261J as it is difficult to find the same part number.

    Links here:
    PME261
    http://docs-europe.electrocomponents.com/webdocs/00bd/0900766b800bd175.pdf

    PME271
    http://www.kemet.com/kemet/web/homepage/kechome.nsf/weben/E7610B7037E8BF028525769C007910E3/$file/F3294_PME271Y.pdf


    Regards,
    Michael
     
  2. jimkeith

    Active Member

    Oct 26, 2011
    539
    99
    The metalized paper capacitor is quite rugged and has a high AC voltage rating--Since it failed, it is most likely a line to line or snubber application.

    The PME271Y will not work--it is polyester and rated for about half the AC voltage.

    What I recommend is the Epcos MKP type--it is polypropylene film and intended for high AC voltage application--very rugged

    For instance a 0.1uf 500VAC (1.6kV DC) capacitor is available from DigiKey:
    http://search.digikey.com/us/en/products/B32654A1104K/495-4194-ND/2269403
    The data sheet is listed on the same page--they have voltage ratings up to 700VAC
    You will have to run it down for your location--perhaps Farnell carries it, but their parametric search engine works poorly, so I used DigiKey's

    Polyester capacitor application above 250VAC is not reliable--the dielectric does poorly for some reason--forget the actual failure mechanism--polypropylene is now the AC capacitor of choice
     
  3. K7GUH

    Member

    Jan 28, 2011
    191
    23
    You don't need the exact same part number. Verify the capacitance and voltage ratings, and replace the aging part with one which meets those criteria. (Roughly the same capacitance value and at least the same voltage rating.)
     
Loading...