Transformer problem

Discussion in 'General Electronics Chat' started by hazim, May 10, 2011.

  1. hazim

    Thread Starter Active Member

    Jan 3, 2008
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    Hi all.

    I have a burnt out transformer for a treadmill and I want to replace it. On the transformer a drawing for two primary windings, one is 220V and the other is 22V, and the secondary winding is 10V. The current/power rating is not mentioned on it but I can estimate it from the size and output voltage together, the transformer is medium in size, I estimate the output current to be 1A.

    Now, it's not easy to find a replacement transformer similar to the original one, because is has another primary winding (22V). I'm thinking to use two transformers, one is 220V-to-10V 1A and the other is 220V-to-22V (but don't know the required current rating needed...)

    But I don't know if this works especially because I'm not understanding why the 22V winding is drawn at the primary side and not secondary where the only power source is the mains 220V source.

    Any idea or help is appreciated :)

    Regards,
    Hazim
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Gimme pictures of the TX and it's connection to the board
     
  3. hazim

    Thread Starter Active Member

    Jan 3, 2008
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    Ok but tomorrow, I don't have a digital camera now in my work. I've tried to take pictures to it by my cell phone but they aren't clear at all.
     
  4. DigitalReaper

    Member

    Aug 7, 2010
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    The 22v winding is probably intended for use in countries that use 240v mains (220v + 22v in series). All you really need is a mains to 10v transformer that can handle the required current (a little headroom wouldn't hurt either, it doesn't need to be exact).

    The real question is what is the required current?
     
  5. #12

    Expert

    Nov 30, 2010
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    I measured 249.6 VAC at my house today, so a 220 winding with a 22V helper winding in series with it would be a serious improvement compared to only a 220 volt winding. This might be exactly what the mfg had in mind.
     
  6. KJ6EAD

    Senior Member

    Apr 30, 2011
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    We should also be exploring the matter of what made the transformer fail.
     
  7. #12

    Expert

    Nov 30, 2010
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    True. Transformers rarely commit suicide.
     
  8. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    I would check the gauge of the 22V winding. It should be same as the 220V one. If it were a primary

    I do not think any one uses 220V + 22V .
     
    Last edited: May 11, 2011
  9. hazim

    Thread Starter Active Member

    Jan 3, 2008
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    Thank you all for replying. I forgot to get the camera with me to work.. so I'll not post a picture now. Anyway I don't think it will help...
    The transformer was burnt out because of a problem in an inverter used at home, it gave high voltage that burned several appliances in the home..
    The electricity service in Lebanon is a long story.. "#12", I always measure the voltage, sometimes I find it around 220V and sometimes less than 110V!! it's really a very bad service in Lebanon. Also it goes off for about 10 hours every day.. this is out of topic. But most homes have an automatic voltage regulator.

    Now, I don't see that the 22V winding is usefull in Lebanon if it's really for protection from higher voltage input.

    R!f@@, the gauge of the 22V winding is less than that of the 220V one (thicker by about 1.5 times).

    So what is the solution? replace with a 220V-to-10V 1A transformer?
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    That means 22VAC is an Aux Secondary Winding
     
  11. hazim

    Thread Starter Active Member

    Jan 3, 2008
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    What do you mean by "Aux"?

    This 22V winding is important as I see on the circuit board.. see this picture I took from my cell phone, it clarifies everything

    [​IMG]
     
  12. #12

    Expert

    Nov 30, 2010
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    Aux is "auxillairy". It just means another secondary. and...if the 22 volt winding is thicker than the primary, it is not a primary helper. It is a secondary like Rifaa said.
     
  13. R!f@@

    AAC Fanatic!

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    Told ya...

    Where is the 10VAC conection
     
  14. hazim

    Thread Starter Active Member

    Jan 3, 2008
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    R!f@@, it is connected to the bridge rectifier by the small white socket, between the medium size electrolytic capacitor and the text box "connected with the 22V winding".

    We considered that 22V winding is a secondary winding regardless what's drawn on the transformer, mainly because the terminals of this 22V winding are connected to a rectifier only and so it's an output not input..

    I have an idea but not sure if it works. Since it's hard to find a 220V-to-22V transformer, I'm thinking about using two transformers: the first is 220V-to-10V 2A and the second is 220V-to-12V 1A (maybe 500mA is enough). Connecting their outputs i series so I get 22V and 10V but with common terminal.

    What do you think?
     
  15. R!f@@

    AAC Fanatic!

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    find a 24VAC TX
     
  16. R!f@@

    AAC Fanatic!

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    Get a 24VAC one, you'll be fine. It can tolerate that much. If you doubt it, get me the filter voltages and it's load area picture
     
  17. marshallf3

    Well-Known Member

    Jul 26, 2010
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    I tend to agree but an ohmmeter will sort it out.
     
  18. hazim

    Thread Starter Active Member

    Jan 3, 2008
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    Back to this thread. Thank you all for help. The transformer is sent to someone who will rewind it for 10~15$.

    Regards,
    Hazim
     
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