rectifier application

Discussion in 'General Electronics Chat' started by richard johnson, Jan 8, 2015.

  1. richard johnson

    Thread Starter New Member

    Jan 8, 2015
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    I have a set of plans for a plasma torch by joe eichholz. the plans recomend using a three phase bridge rectifier versus a single phase bridge four conductor. Theres no instructions or diagrams how to hook up the three phase
    any one know how this would hook up .I have every part and piece and I'm stuck right up front.I have intensely perused this sight and it is way cool.Thank you any help would be so welcome
     
  2. GopherT

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  3. richard johnson

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  4. GopherT

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    Assuming you have access to a three phase source, you connect one phase to each terminal showing a sine wave symbol and DC comes pouring out of the two terminals showing (-) and (+).

    If you don't have three phase, you will need some type of big rotating machine to convert single phase to three phase.

    Also, you will need a good understanding of electrical safety practices, fuses, enclosures, circuit breakers and grounding so you don't hurt anyone.
     
  5. BillB3857

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    Doesn't it have markings to show +/- and the 3 phases?
     
  6. richard johnson

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    Jan 8, 2015
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    yes it does all of the above.5 terminals
     
  7. BillB3857

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    Then that's how you hook it up.
     
  8. richard johnson

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    Jan 8, 2015
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    Can the transformer ground act as third leg I just got my transformer today it weighs 60 poundsI havent looked at it yet .That will probably answer a few questions thank you Bob
     
  9. BillB3857

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    Did you get a 3 phase transformer? Delta or Y connection? If Y connection, how may wires coming out of secondary?
     
  10. MaxHeadRoom

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    You cannot use ground as a conductor, usually a simple full wave 3ph rectifier has three AC inputs and the two DC +- out.
    I cannot see a reason for using a 3ph rect on 1ph, if you connect one of the conductors to two inputs you are just increasing the current capacity of that part of the bridge.
    Max.
     
  11. richard johnson

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    Jan 8, 2015
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    Checked and my transformer is an upstep 110- 220 or 440 .with 110 input 2 lead and dual lead ouput 220. my bridge shows 1 in complete loop ground and two other terminals I would say positive .whats next
     
  12. MaxHeadRoom

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    If your Tfmr is two conductor secondary it is single phase, and using the usual 3ph rectifier full wave 6 diode rectifier bridge is no advantage.
    What is 'complete ground loop'?
    Max.
     
  13. alfacliff

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    Dec 13, 2013
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    single phase would require filtering for a plasma torch. a high current plasma torch would require lots of fitgering.the overlaping three phase in the rectifier makes for a very smooth dc output without a lot of filtering.
     
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  14. richard johnson

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    Jan 8, 2015
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    how would it wire up with my single phase txfmr
     
  15. MaxHeadRoom

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    If you are talking about the 3ph rectifier on 1ph, then you only use two of the AC input terminals.
    Max.
     
  16. MaxHeadRoom

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  17. richard johnson

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    Jan 8, 2015
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    which two 1-2-3 That is thelayout of the recti looking down on the posts (conections) thank you so much for your help
    + -
     
  18. richard johnson

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    Jan 8, 2015
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    yepers thats it do you see anything that needs changed
     
  19. MaxHeadRoom

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    The 3ph bridge in the pic shows 6 terminals???
    Normally there is 3 ac in, pick any two for the 1ph AC in, the output is the same, +- DC.
    You should also be able to use a standard 4 terminal 1ph bridge, unless you already have the 3ph, if so name the part No.
    Max.
     
  20. richard johnson

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    Jan 8, 2015
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    the only thing on the bridge is this century 3phase SQL60A 1200v power semiconductor electronic it has a diagram the three terminals and one positive and one negative it shows six diodes huge heat sinc
     
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