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12VDC inverter system

Discussion in 'Electronic Repair' started by [email protected], Jun 4, 2008.

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  1. Guest

    We have a customer who owns a series of 24 and 30 unit apartment
    buildings. Presently on each floor as per local requirements there are
    several self contained emergency lighting units. Some of these are
    equipped with a small 6V battery and just two low voltage lamps that
    aim in different directions down the hallway, while other larger units
    having larger batteries sometimes might have as many as six 12volt
    lamps wired remotely. These all are equipped with sealed lead acid
    rechargeable batteries which need to be replaced every few years. Two
    of his buildings are exceptions though and don’t have this type of
    lighting. In these buildings, the hallway lighting circuit is wired
    through an inverter system. This system, which was built by a company
    in Massachusetts many years ago is installed in the boiler/electrical
    room, and consists of two 12VDC to 120VAC 450W solid state inverters
    operating in parallel and two group 24 size wet cell automotive
    batteries. There is a built in charger and a huge contactor which
    drops out upon loss of AC and applies 12VDC to the inverters. Loss of
    AC will cause the load to toggle over to the inverter outputs and the
    hallway lighting circuit remains powered. Maintenance on these two
    buildings is minimal and his ultimate cost savings projection becomes
    significant when multiplying installing this type of system into the
    100’s of buildings which he presently owns. He has asked me to look
    into finding this type of equipment for him to retrofit his other
    buildings. The typical load is about 400W CFL and will probably never
    exceed 550W. I don’t know how picky these particular 13W CFL units are
    to anything other than sine wave AC. I know sine wave or even modified
    sine wave will probably increase cost somewhat. Does anyone have any
    ideas for inverter systems equipment they might be able to share with
    me? Thanks, Lenny.
     
  2. Guest

    How bout salvaging some old computer UPS from the local dump or
    advertize to relieve folks of their defunct units for recycling

    al
     
  3. jakdedert

    jakdedert Guest

    Whatever he gets will need to be inspected and approved. The regs in
    most municipalities are much more stringent in commercial buildings. I
    don't think he's going to convince Codes that a solution based on
    salvaged, repurposed pc hardware is going to do the trick.....

    jak
     
  4. PhattyMo

    PhattyMo Guest


    CFL's _Shouldn't_ be picky about power. They are usually always
    rectified to DC inside.Sine,Square,sawtooth even-it doesn't matter to
    the rectifier.
     
  5. Arfa Daily

    Arfa Daily Guest

    I'm not too convinced by that argument. The inverter squeezed into the base
    of these lamps, is by necessity very small, which only allows for a filter
    cap of around 10uF. It is often this cap that fails in these lamps, so
    clearly, it is stressed already, by the heat, and the job it's trying to do
    filtering the raw DC from the reccy. I reckon that if you start hitting it
    with a real bad shaped waveform, it might be just a bit too much for it.
    Bear in mind also that these things are inherently electrically noisy, and
    only just about squeeze by the RF emission regs - at least here in the UK -
    with a sine wave going in. With a rough wave being supplied, they might just
    kick up enough radiation, to cause a problem.

    Arfa
     
  6. James Sweet

    James Sweet Guest


    A lot of these low wattage CFLs where the ballast is part of the fixture
    still use magnetic choke ballasts. In my experience they do still work
    on inverters, but they tend to buzz and are more reluctant to start.
     
  7. jakdedert

    jakdedert Guest

    There are going to building codes issues that will mandate some sort of
    purpose-built commercial solution to your problem. IME, you won't be
    able to home-brew something of this sort. The potential liabilities if
    someone is hurt in an emergency situation are too great...even if it
    can't be directly attributed to the performance of the system.

    I'd just google 'emergency lighting' or 'backup lighting'; see which
    companies supply such things and bite the bullet. In fact, having just
    done so ("emergency lighting"), I got 1,940,000 hits. I'll bet there's
    an answer there somewhere. For instance,
    <http://www.emergencylighting.com/category/Inverters.cfm> is one of the
    top results. Clicking that site, then category 'inverters' shows about
    40 different products.

    jak

    jak
     
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