Hey ! Transformer Experts.

Discussion in 'General Electronics Chat' started by R!f@@, Feb 21, 2014.

  1. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    I have big big transformer.
    Wait that came out wrong. :eek:

    What I mean to say is that I have these to play with

    [​IMG]

    [​IMG]

    [​IMG]

    Questions.
    1. The last one confuses me. Is it a U type or R core.
    I can't seem to find the primary of the last. I connected mains to the two orange cable and BANG ! The guy next to me ran away. :D Just the breaker tripped.
    Yellow sheathed wires are the secondary that I am sure. The twisted cables are center tapped windings from each side. 3 wires from each bobbin.
    So Should I connect these to the primary and check.
    By the way I got two of these and they came from a Peavey Amp. Two units in one amp.

    2. Which one will be easier to wind. That is the secondary for my requirements.

    Ps. All are of same size.
     
  2. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    Hey I would the first one for free shipped lol



    Looks like fun and I just picked up a microwave transformer..
     
  3. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    I am not shipping any thing dummy.
    Do you ever think this would be cheaper.
     
  4. PackratKing

    Well-Known Member

    Jul 13, 2008
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    EGAD !!! :eek: That is one nice toroid in the first pic... not to mention one helluva nice capacitor bank...
    Far from being an "expert' with transformers, I am however, doing my best to learn the ropes...

    Pix, are of a unit out of a 1000 watt UPS.

    Using Don Q's method of phasing, I reconfigured the double-output coil of #8 wire, which was only putting out 24.3 volts... It now puts up 48.6...

    I know that #3 pic looks really screwy, with the output coming up out of the center of the coil, but it works. Using other input, I can get a max of 59 volts out of the #8 coil... output amps equal to input...
    An idea of size... that is a 6" scale on top of pic 1 ... the thing weighs nigh 40 pounds...

    Pic 2... Blue/white on left, are the original primary. the five-color, are another single, multi tapped coil, Black being common for output, that can be used either for a primary or an output.. all leads / coils are are #16, except that magnificent #8... This is going to be a kick-ass bench supply...

    I have 4 other 600 watt units... each can be driven with enough primary voltage to pull 12+ volts out of the #8 with enough to supply a series-pass regulator...
     
    Last edited: Feb 21, 2014
  5. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Have question though.

    When we use UPS transformers, say in ur case a 1000W UPS.

    So is it safe to assume that the UPS transformer rating will be 1000VA give or take few ?
     
  6. PackratKing

    Well-Known Member

    Jul 13, 2008
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    I always got a kick out of " VA " when Volts X Amps = Watts anyway...

    Wiseguy aside, yes, they are very close, though I would derate about 2 % just to be on the safe side...

    When hooking up something that big, make sure ALL grounds are hooked up... especially any that serve to ground between-coil capacitance... Otherwise, you may get sparks when hooking up to backdrive it for test when it discharges... ergo the advice to do these tests at lower voltage...

    When you energize at rated working voltage, it will make a brief, very audible grunt as the core magnetizes... this is no problem as long as coil phasing is right... if not, it will complain vigorously...
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Another couple of tips, if no info on the transformer and the inner most winding connection can be seen, this will be the primary.
    Two: On a Toroidal type, make sure the top of the centre bolt is not also secured or touching the case or chassis, otherwise the transformer gets very HOT quickly.
    Max.
     
  8. BobTPH

    Active Member

    Jun 5, 2013
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    This thread has given me a bad case of transformer envy.

    Bob
     
  9. tcmtech

    Well-Known Member

    Nov 4, 2013
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    Then I am not going to post pictures of my collection in the shop. It would put you into a sleepless jealous rage for weeks! :D
     
  10. R!f@@

    Thread Starter AAC Fanatic!

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    I will post soon.
    By the way these are not the only ones I have. I got plenty of big ones stored.
    The Last picture is something I got couple of days ago and it is the only one that gave me a bang trying to figure out the primary.
     
  11. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Still...No one replied about witch was is easier to rewind the secondary.
     
  12. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    OK. So If I have a 650VA UPS transformer and the secondary puts out 14VAC, is it safe to assume the secondary can handle 650VA/14VAC =
    46Amps.

    This is what I always figured.

    Just need to be positive. I will need the correct info as I am going to meddle with these babies
     
  13. Gdrumm

    Distinguished Member

    Aug 29, 2008
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    Would they make good boat anchors?
    The one on the bench photo looks like it weighs 70 lbs. or more.

    I bought a welding transformer that required a forklift to load in the pickup truck.
    I failed to tie it down, and at the first stop light, it slammed into the back of the cab, and made a nice dent.

    It didn't hurt the transformer at all, but I had a heck of a time telling the boss, because the pickup truck was almost brand new.

    Lesson learned, tie it down.
     
  14. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It is a toss up out of the 2nd and 3rd, the 3rd one however looks like the lamination have retaining screws, If you felt ambitious you could dismantle and make is easier to wind the secondary coil.
    (Oops I see they both have the lamination screws).
    EI and the like are always a pain, my choice now is to purchase toroidal every time.
    So much easier to add or remove a winding.
    Max.
     
    Last edited: Feb 21, 2014
  15. PackratKing

    Well-Known Member

    Jul 13, 2008
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    I dunno Riff... will your leads / magnet wire handle that kind of power ???

    I'm not too sure I would pack that kind of juice through it...

    Does it have a large-wire [ 12 or better ] orig. secondary ? what guage are the original primary leads / magnet wire ... I see some of the heavy leads are bifilar...

    Fan all those leads out a wee better, and indicate their guage...
     
  16. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    The calculation was just to confirm theory.
    I know 46 Amps is no way for tht transformer.

    But wouldn't it be true.

    I will see what I can do to measure the gauges. I only have a vernier caliper.

    Is it possible to figure out roughly the amount of current capacity by measuring the gauge of the secondary winding.

    Why do you call magnet wire. Isn't it just enameled copper wire ?

    All transformers are like 40 to 50 lbs I believe.
     
  17. R!f@@

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    The toroid picture is from a amp in repair but I do have a second toroid from the exact amp. Cannot lift it easily so I am showing that picture.

    I can take apart the toroid easily can't I ?
    The question is how can I take away the potting in the middle easily.
     
  18. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The core size as well as winding gauge decide the VA.
    If it is 650 VA then if you can obtain #8 or #6 gauge wire it should handle the current.
    It is commonly called magnet wire.
    The 3rd candidate may be the one to dismantle as UI is a little better than EI lamination type to reassemble.
    There is no need to take the toroid apart, but the potting can usually be carefully punched,drilled or pecked out, the winding is being modified anyway.
    Placing or reading a few turns will establish the turns/volt you need.
    Average around 2-3.5t/volt.
    Max.
     
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  19. wayneh

    Expert

    Sep 9, 2010
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    Those are the same thing, to me.
     
  20. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    I thought so.

    And guess what ? Me got another lovely Power Transformer from those hefty Yamaha Amps. :D
     
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