So in a 3 phase induction generator with coils for the stator and magnets for on the rotor, I am wondering if the the current induced in the coils would create a magnetic field that would oppose the rotation of the magnets on the rotor?
Electronic – Will a 3 phase induction generator fight its own rotation
acelectric-machineelectromagnetismgenerator
Related Solutions
When the synchoronous generator loaded, an angle δ occurs between stator magnetic field and rotor magnetic field. It is called "load angle". Hence the IA represents the stator magnetic fied and the BS is now perpendicular to this surface. Now the terminal voltage VΦ is related to Bnet, Bnet=BS+Br. You can observe exact load angle δ between VΦ and EA in your figure (d). Also the load angle δ is shown on voltage vector diagram between Ea and VΦ. Sorry my poor English. I hope i can explain it.
Yes, a magnet that is moving such that it creates a current in a non-moving wire will feel a force resisting that motion.
You can make a generator with spinning magnets instead of spinning wires like this one...
As the magnets move, they induce a current in the wire. The induced current itself make a magnet field on the opposite direction, opposes the rotation of the magnets.
Keep in mind that the lines of magnetic force must be cutting though the wire to induce a current in it, so just rotating a magnet around a wire such that one of its poles is always pointing toward the wire will not induce a current, and therefore will not create a back force.
Also keep in mind that it is the current flowing in the wire that creates the field that creates the back force, so the wire must be in a circuit or else no force. You can demonstrate this by spinning an unconnected stepper motor with your fingers, and then shorting the wires and spinning it again. It is harder to turn when the wires are shorted. Most stepper motors have fixed coils and turning magnets btw.
If you are interested in electromagnetics, I'd highly recommend this book...
Electricity and Magnetism 3rd Edition by Edward M. Purcell
Yo can find a free PDF version on google.
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Best Answer
Yes, any generator will be subject to this effect.
You can't get something for nothing, so the more current drawn from the coils, the larger the (opposing) magnetic field (counter mmf) and the harder the rotor will be to turn.
If this didn't happen then the amount of energy required to turn the rotor would not change according to the load on the output, which would break the laws of physics.