Toroidal shaped inductor cancel induced voltages

[qdnboy]

Could someone explain how a toroidal coil that is would uniformly around the core, would be able to cancel out induces voltages from an eternally applied magnetic field?
Thank you!

 

[FvM]

Can you explain, why an external field should induce a voltage in a rotation symmetrical (toroidal) coil? It can't.

A hint for analyzing the problem: It also works without a core.

 

[qdnboy]

Due to the winding, the induced current will be about the same magnitude at each half of the toroid but opposite in direction, thus, canceling out each other. Thanks!

 

[FvM]

Yes. However, in an inhomogeneous field and with finite toroid diameter, the cancellation isn't complete.