Question

What would happen if I took a toroidal core, generated a static toroidal magnetic field in the core and then rotated the core around it's symmetry axis within a larger stationary toroidal winding around the same core? Just for simplicity imagine a toroidal transformer with a rotating core inside.

Would I get DC current generated in the stationary coil? If yes can anyone explain by what law and formula?

Answer 1

Rotating a toroidal core with a static magnetic field inside a stationary toroidal winding will not induce a current because Faraday's law requires a change in magnetic flux, which does not occur in this scenario.

Step-by-step explanation:

Based on Faraday's law of induction, a transformer works on the principle of inducing an electromotive force (EMF) in a secondary coil due to a changing magnetic flux linked with it. In a toroidal transformer with a rotating core, if you have a static magnetic field (i.e., not changing with time) and rotate the core about its symmetry axis, you will not induce a current in the stationary winding. This is because the magnetic flux through the secondary would not be changing—Faraday's law requires a change in magnetic flux to induce an EMF. For a DC current to be generated in the stationary coil, there needs to be a time-varying magnetic field. Rotation of the core itself doesn't change the magnetic field through the windings, given the field is static and symmetric with respect to the axis of rotation.