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Where to get HV caps? 5-6 KV, 0.01-0.1 uF

Discussion in 'Electronic Components' started by [email protected], Apr 27, 2007.

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  1. Guest

    Hello all!

    My electronic air cleaner has quit working and I have narrowed it down
    to the HV power supply. Right now I am suspicious of the capacitors,
    particularly because the wax (?) on the end of one of them seems to
    have melted. Since they are about 23 years old I plan on replacing
    all three of them.

    There is one capacitor directly across the AC input that is rated
    0.011 uF, 4 KV AC. There are two more that I think form part of a
    doubler that are rated 0.1 uF, 5 KV DC. Each of the three are about
    1" diameter by 3" long (25 mm by 75 mm).

    A turn through the Digi-Key and Mouser catalogs didn't find anything
    suitable. The case size and lead arrangement is fairly non-critical,
    because I have lots of room to work with. I can get an entire
    replacement power supply for $120, but I'd like to try fixing this one

    Any suggestions on where to buy capacitors like this in small


    Matt Roberds

  2. Have you checked with the OEM of the electronic air cleaner?

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  3. Try ebay.

  4. I'm not the one looking for them. You snipped the wrong parts of the
    message you replied to.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  5. Not always a bad sign.
    Try locally?
  6. Ray King

    Ray King Guest

    Hi, Matt,
    To be safe you might check the high voltage diodes ( usually a doubler )
    Sometimes they can look similar to a cap. There are usually two caps and two
    diodes. Sometimes the two diodes are in the same package with three leads.
    Or in a larger plastic block.
  7. Guest

    "You'll kill yourself! But if you manage not to kill yourself, you need
    to buy our replacement power supply for $120."

    Not always a bad sign.[/QUOTE]

    Well, the HV transformer appears to be putting out - the secondary is not
    open, and when the primary is powered with 120 V, the secondary is
    something more than 750 V AC open circuit. When I connect the secondary
    to the diode/cap board, with the DC output unloaded, the voltage across
    the secondary collapses to zero. Measuring across the input to the
    diode/cap board with nothing else connected, I get about 130 ohms. Given
    that the input is probably 3 or 4 KV AC, this implies an input current of
    over 20 A, which doesn't seem likely.

    It is a doubler circuit, with an additional capacitor directly across
    the AC input. The diodes look like normal diodes, just bigger - maybe
    0.25" diameter by 1" long (6 by 25 mm). Neither diode is a dead short
    but my DMM's "diode test" range can't convince them to conduct, either.
    I think I need to test them with something more than the 9 V the DMM
    can put out, though.

    Matt Roberds
  8. Try a 12 volt (or variable) wall wart with a 1 K resistor in series.
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