Induction vs electromagnetic repulsion: which is more efficient?

[MaJiK9021]

Hi, I am curious about the most efficient method of levitating an object. I am considering using electromagnetic induction or the repulsion between a magnet and electromagnet. Which would require less energy? Also I am aware of Earnshaw's law; let's ignore the complexities it causes for now.

Also, is it possible to produce a repulsive force through induction, if the electromagnet is not moving in relation to the conductor? Say, if the electromagnet and the conductor are fixed in spot, but the electromagnet has an alternating magnetic field.

Any help would be appreciated.

 

[Bob S]

Also, is it possible to produce a repulsive force through induction, if the electromagnet is not moving in relation to the conductor? Say, if the electromagnet and the conductor are fixed in spot, but the electromagnet has an alternating magnetic field.

Yes, eddy-current repulsion is possible whenever there is a conducting loop or plate in a dB/dt field (Faraday's law). The induced currents are replused by the magnetic field (Lorentz force). It is sometimes used in circuit breakers, for example.
Bob S
[edit] See section on eddy current repulsion in
http://en.wikipedia.org/wiki/Eddy_current
[edit] There cannot be an axial force on a conducting ring with azimuthal induced currents unless the magnetic field has an r component (i.e., has a dB/dz gradient).

 

[oswaler]

Both electromagnetic induction and electromagnetic repulsion can be efficient methods for levitating an object, but the most efficient method will depend on various factors such as the size and weight of the object, the distance it needs to be levitated, and the availability of energy sources.

In terms of energy usage, electromagnetic induction would generally require less energy as it involves the creation of a magnetic field through the movement of a conductor, rather than the constant use of energy to maintain a repulsive force between two magnets. However, this also depends on the strength and efficiency of the electromagnet used in the repulsive method.

Regarding the possibility of producing a repulsive force through induction without the movement of the electromagnet, it is possible but not as efficient. This is because the alternating magnetic field would need to be strong enough to continuously induce a current in the conductor, which would require a significant amount of energy.

In conclusion, both methods have their advantages and limitations, and the most efficient method will depend on the specific circumstances and requirements. It is also important to consider the limitations of Earnshaw's law before implementing any levitation method.