Lighting transformers

Discussion in 'General Electronics Chat' started by ISB123, Aug 20, 2016.

  1. ISB123

    Thread Starter Well-Known Member

    May 21, 2014
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    Hello, while I was looking for some transformers for a PSU build I stumbled upon "lighting transformers" which were fairly cheap, most likely because they are mass produced. To me they look like standard torrid transformers. On label it says "intended for use in halogen lighting only." Is it because they have thermal switch built in?
    Specs:
    250W
    220V/11.5V 50Hz

    [​IMG]
     
  2. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    Take another photo with the electrical ratings showing, please.
     
  3. ISB123

    Thread Starter Well-Known Member

    May 21, 2014
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    This one has more power but the rest is the same. Spec. for 250w
    Weight:2.6kg
    Height:48mm
    Radius:127mm
    Eff:95%
    [​IMG]
     
    Last edited: Aug 20, 2016
  4. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    I have no experience with them...but my guess is that it'll make a fine high-efficiency, low-noise step-down transformer.
     
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  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The nice thing about Toroidal's is they are easy to add over-winds or different secondaries as needed, usually about 1.5 to 2 turns/V.
    Max.
     
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  6. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Beware language barriers! If 'halogen lighting' indeed refers to 'incandescent's (as one would expect) then all's well and good (i.e. I agree with @joeyd999 {Post #4}) -- On the other hand should said devices be designed as ballasts for metal halide lamps, you may expect them to be current limited (via leakage inductance), to operate at rather high OC EMFs and, perhaps, be wired/wound as 'auto-transformers'...

    Best regards and good luck!
    HP:)
     
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  7. ian field

    Distinguished Member

    Oct 27, 2012
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    Its often referred to as; "low voltage lighting" - so an auto-transformer could potentially be a contradiction in terms.

    Toroids probably don't like large voltage transients - so large inductive loads that produce a big fat spark when you break the current, could make you wish you'd included a primary fuse.
     
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  8. Hypatia's Protege

    Distinguished Member

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    I agree assuming the intended lamps are indeed incandescents (which, based upon labeling, etc. seems to be the case) -- as opposed to HIDs

    I'll take your word for it - but inasmuch as the 'why of it' escapes me - please explain?:confused::)

    Best regards
    HP:)
     
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  9. ISB123

    Thread Starter Well-Known Member

    May 21, 2014
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    I found the manufactures datasheets. It says that transformer has a thermal switch on the primary winding.
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Unfortunately in some instances it is a thermal type fuse and if buried without the ends exposed, it renders the Tfmr useless if and when it blows, if one is lucky the the ends ARE exposed and can be shunted out.
    Max.
     
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  11. Hypatia's Protege

    Distinguished Member

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    À la a perfectly good refrigeration compressor but for a 'stuck' internal OCP interrupter:mad::rolleyes:

    Best regards
    HP:)
     
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  12. ian field

    Distinguished Member

    Oct 27, 2012
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    AFAICR: They have less turns per volt than a conventional transformer - therefore; greater voltage stress on the insulation.
     
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  13. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Simple to find out, a 10 turn overwind would tell, the ones I use are usually as post #5.
    Max.
     
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