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Bifilar coil

  1. Apr 19, 2013 #1
    I have a doubt bifilar coil makes its self inductance zero... do we get any field around this coil or it also cancels the field around it and makes net field zero..?
  2. jcsd
  3. Apr 20, 2013 #2
    self inductance is lowered in these coils yes but it surely doesn't cancel any field around it as long as current is flowing through it.
    You can't cancel a field like that.
    Usually they are nothing more than just a different way to make a coil or sometimes when you have two smaller wires instead of one bigger you use them in parallel and now that counts as bifilar coil.

  4. Apr 20, 2013 #3
    So can i use them for my application of wireless power transfer ..?
  5. Apr 20, 2013 #4
    Wireless power transform is not so much dependent on the single wire or bifilar one than the way the wire is wound and the frequency going through it.
    Also because wireless power comes in very high frequencies just like radio waves only works for a much shorter range , you should consider litz wire , it is a wire were a single conductor is separated into many smaller strands of conductor , this is usually done for high frequency because of the skin effect. Skin effect is when high frequency AC passes through a conductor the majority of current tends to pass on the outside of the wire rather than the whole wire so as higher the frequency the more this effect comes into play.


  6. Apr 20, 2013 #5
    yeah am taking care of skin effect and what am thinking is to use litz wire conductor and wind in bifilar method will it be okay to do so..? will it have more field compared to unifilar winding..? and i have a doubt out of cylindrical shape coils and bifilar flat spiral coils which one produce more field each have same diameter
  7. Apr 20, 2013 #6
    Have you tried google? it has pretty much of amateur forums and other sites with this kind of information but beware there are alot of misinformation also , now try a search read some stuff and if you still have questions come here and ask.

    No offence but some questions are easy enough that you can find them yourself.
    Bifilar is okay just as much as single litz wire is okay because when it comes to high frequency the bifilar coil already is a litz wire so if you have a litz wire with say 5 strands I think it is pretty much okay , for further information you either have to see some sources or conduct experiments and see in real life under what type of wire wound you can get the best field strength and angle.
  8. Apr 20, 2013 #7


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    Why are you using two threads to discuss the same topic?
    You are using the term "bifilar" wrongly. The wiki article on "bifilar coils" gives you all you need to know. If you want a low loss coil, look up Litz wire and find the frequencies it is used for and what it consists of. You have not told us any details of your Wireless Power system so you can't expect a useful answer yet. As Crazymechanic says, try looking this stuff up for yourself. You are the only person who knows your level of knowledge so far and PF answers will either be too easy or too hard for you.
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