Rewiring transformer - question on wire arraingement

Discussion in 'General Electronics Chat' started by RogueRose, Jun 18, 2016.

  1. RogueRose

    Thread Starter Member

    Oct 10, 2014
    I'm rewiring a number of MOT's and was wondering if how the wires are arranged makes a difference. Depending upon the answer I can use more wire lengths or less.

    I plan on using a minimum of 6 lengths of wire, all will be the same length, but if possible I may go to 12 (or maybe 18) lengths at 1/2 the length of the 6.

    What I want to know is if I wrap on length around the very inner core and then another wire on top of that, so layer 2, then wire 3 would be layer 3, etc. Each length would have a little less turns but the total length would be the same. This type of setup would be ideal for getting the most wires in the transformer

    The other option is to start all 6 at the same point, the inner section, but this is MUCH more difficult and I don't think I can get as many strands in this way.

    Also there are some metal (iron?) shims between the primary and secondary and have read that these should stay and some say to remove them. What do you guys suggest? It is about 1/4-1/3" thick and about 8-10 plates the thickness of each of the outer core plates.
  2. DickCappels


    Aug 21, 2008
    What is the purpose of this transformer? The ultimate use would dictate the answers to your question.
  3. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
    The described procedure will facilitate development of multiple secondaries or a single secondary provided (in the latter case) that you are mindful of phasing and exercise caution as regards formation of 'short-circuit loop{s}'...

    I do not advise paralleling windings! -- If you require more current handling capacity either use a 'heavier' conductor or parallel the conductors prior to installation on the core!

    Said laminations form magnetic shunts -- They should be removed for all applications non-requisite of 'ballasting' (i.e. reactive current limiting).

    Best regards and good luck!
  4. Picbuster

    Well-Known Member

    Dec 2, 2013
    I agree with DickCappels.
    Length of a wire has no influence on the transformer electrical behaviour the windings are.
    The Frequency, core material air cap and distance between the windings are all linked.
    Frequency goes up core can be reduced so are the number of windings but the impedance between the wires could put you in trouble.
    We need more information as Dick indicated.
    Hypatia's Protege likes this.
  5. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
    While I concur with the 'gist' of your argument, in principle - I hasten to point out the fact that MOTs operate in saturation under the best conditions -- hence conscientious, nuanced design considerations aren't likely germane to the OP's application (which being, IMO, quite likely a spot welder, TC driver, carbon-arc search lamp, etc...) anything more 'refined' will require re-winding of the primary as well...

    Best regards