Is it possible to create a continuously turning ring-like superconductor (with a current in it) by placing the current-carrying superconductor in a magneyic field?

  • 2
    $\begingroup$ How much energy does it take to keep it cold enough for superconducivity to continue? $\endgroup$
    – user108787
    Commented Sep 9, 2016 at 10:16
  • $\begingroup$ Assuming conditions are ideal, isolated vacuum system with a very long lasting magnet, temperature doesnt increase because there is no resistance in the metal nor air resistance, then would the ring-like superconduxtor continue to turn without spotting but instead continuously spinning? $\endgroup$
    – user129684
    Commented Sep 9, 2016 at 10:30
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    $\begingroup$ I am no expert, but I feel as soon as you try to extract energy from it (otherwise it's a lovely toy but not much else), you will cause heating through friction, or provide a path for heat to enter the system, (or other ways that I don't know enough about to say) and once that happens, you will need to use energy to remove that heat. Perhaps it would keep spinning, as the moon will keep going around the earth, for any arbitrary time, but if we tried to take energy out of that gravitional system , we get the 2nd law popping up. Best of luck with a proper answer though. $\endgroup$
    – user108787
    Commented Sep 9, 2016 at 13:10
  • $\begingroup$ Related: physics.stackexchange.com/q/121255/2451 and links therein. $\endgroup$
    – Qmechanic
    Commented Sep 9, 2016 at 14:56

1 Answer 1


If we considered the loop of superconductor carrying current then magnetic field will also generate around conductor. And from the magnetic field we can produce energy. And the amount of current in conductor will remain same


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