2 wire transformer

Discussion in 'General Electronics Chat' started by dick56, Aug 23, 2012.

  1. dick56

    dick56

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    I have a 2 wire transformer from a circular flouresant light. The transformer markings are, LEON -400, 118 volt, .32A, 22W. The transformer is burnt and there is no resistance between the two wires. I have never encountered a transformer with only two wires so I do not understand how this works. I do know that one wire is connected to one side of the 120 volt AC input and the other wire is connected to the on/off switch. The black 120 volt AC in line is connected to pins on the circular light. There is a green 120 volt input wire which is connected to the metal frame where the transformer sits although the transformer has an insulating cover surrounding the transformer.

    Any ideas how this works and what voltage is needed to make the flouresant light work? A search of the web does not show any transformer with these numbers. I would like to get a transformer to make this light work.
    Thank you.
     
    dick56, Aug 23, 2012
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  2. dick56

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    It's a ballast, an inductor designed to limit the current to the lamp.

    The numbers you have read off the ballast should be sufficient for you to find another one.
     
    (*steve*), Aug 24, 2012
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  3. dick56

    john monks VIP Member

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    Steve is correct. The ballast typically connects to the hot line then to One terminal of a fluorescent light filament. The neutral line connects to one terminal of the filament on the opposite end of the fluorescent light. There is a pushbutton or starter connected between the remaining filament leads on opposite ends of the fluorescent light. Now what happens is when the starter or button is closed current passes from the line through the ballast and the filaments light up causing a conductive plasma to occur around the filaments. This helps liberate electrons from the filaments. So now then the button or starter is opened whatever current that was passing through the ballast wants to continue to keep going because ballast tend to resist the change of current. So for the current to keep going the voltage spikes causing the gas in the fluorescent light to ionize and therefore causing it to conduct and the light lights up.
    Typically a light runs around 30 volts. But it may take 1000 volts to start the light. Technically a fluorescent light is an arc light. This is why a ballast is used.
     
    Last edited: Aug 24, 2012
    john monks, Aug 24, 2012
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  4. dick56

    dick56

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    Steve and John, thanks for the replies. I Googled 2 wire transformer and the numbers, but no hits. Is it possible to put another step-up three wire transforner in the burnt out ones' place? Maybe a 4 to 1 step-up to see if that is enough to light the phorsphors?? What wires of the three wire transformer would be the ones to use?
    Thanks again.
     
    dick56, Aug 24, 2012
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  5. dick56

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    (*steve*), Aug 24, 2012
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  6. dick56

    davenn Moderator

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    no, you must use a proper ballast inductor and while you are at it replace the fluro tube(s) and starter(s) :)
    understand its NOT a transformer there is no transformation of voltage

    They are a very standard item, follow steve's link for dozens of hits :)

    cheers
    Dave
     
    davenn, Aug 24, 2012
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  7. dick56

    JMW

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    This sounds like an 8 inch or so Circline lamp. If so, you can probably buy a new one for less than a ballast. If your lamp has some intrinsic value e.g. your mother in law gave it to you or it matches the other 40 or so in your home, buy a new one, remove the ballast, starter and lamp and install it your existing fixture.
     
    JMW, Aug 30, 2012
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  8. dick56

    Electrobrains VIP Member

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    If you want to understand the function of a normal Fluorescent lamp, you can find good information in Wikipedia: Fluorescent lamp Starting

    It's right, as pointed out that the ballast is limiting the current in normal mode, but it also works as a "2-wire transformer" in a type of "flyback mode" together with the starter at start-up.

    You can simplified say it like this: When the starter is closed, the "2-wire transformer" stores the energy in its magnetic field (works as a primary winding).
    When the starter opens, the magnetic field is "pushing" the energy out of the "2-wire transformer" (works as a secondary winding), resulting in a very high voltage.
    This happens because the circuit is open and the energy must go somewhere, in this case it just raises the voltage higher and higher till a sparkle appears - hopefully inside the tube!
     
    Electrobrains, Aug 31, 2012
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  9. dick56

    szhighstar

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    please advise input volltage and current/ouput voltage voltage and current/ work frequency in your circuit, then recommend which transformer you should be select.
     
    szhighstar, Sep 2, 2012
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  10. dick56

    davenn Moderator

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    read the first post and get the information you asked for
    Then read on and understand the type of INDUCTOR the OP requires

    Dave
     
    davenn, Sep 2, 2012
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