What causes magnetic reversal?

Answer 1

If you draw this out, it should become clear:

Starting -------------------------------> Ending

Phase 1: I angle 0 (switch with 3) I angle 120

Phase 2: I angle -120 I angle -120

Phase 3: I angle 120 (switch with 1) I angle 0

From the starting position, you see phases 1-2-3. Since phase 1 and 3 are swapped at the ending position, their order would swap as well, so you would see a phase rotation of 3-2-1. If you drew these out you would see a clockwise rotation one way, and a counter clockwise rotation the other way.

Answer 2

The magnetic dynamo (molten iron core) that drives Earth's magnetic field would have to change direction or somehow flip around. This has happened many times in the past, and will happen again at some point.

Answer 3

A flow of current through a conductor will set up a magnetic field around it. This magnetic field has a north and south pole, just like a permanent magnet. If you reverse to direction of flow (exchange + and - poles) the North and South pole will also be changed.
Motors work by the magnetic fields either attracting or repelling each other. (opposites attract, same poles repel)
So reversing the flow, will change the poles and what used to attract, will now repel. So the motor will rotate in the opposite direction.
This will be so, for motors that have a permanent magnet construction. If field and rotor are electromagnetic, and fed by the same source, both fields will change and have a net result of no change in direction.

Answer 4

Why does switching the current flows in any two phases reverse the direction of rotation of stators magnetic field

Answer 5

because it is stupid

Answer 6

yes!