Our group project:
Pictures of our project:
videos:
http://www.youtube.com/watch?v=j3QMgKPdMt8&feature=related
http://www.youtube.com/watch?v=icpGonZljvA&feature=fvw
http://www.youtube.com/watch?v=OEExd0wlsPo&feature=related
Magnetic Levitation
Student Names:
1. Faisal Zahran AL Maamari
2. Mohammed Nasser AL Dhaheri
3. Ahmed Juma AL Azizi
Grade: 12.02
Introduction
Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields. Magnetic pressure is used to counteract the effects of the gravitational and any other acceleration.
Magnetic levitation is used for maglev trains, magnetic bearings and for product display purposes.
Magnetic fields are actively excluded from superconductors (Meissner effect). If a small magnet is brought near a superconductor, it will be repelled because induced super currents will produce mirror images of each pole. If a small permanent magnet is placed above a superconductor, this repulsive force can levitate it. The black ceramic material in the illustrations is a sample of the yttrium-based superconductor.
By tapping with a sharp instrument, the suspended magnet can be caused to oscillate or rotate. This motion is found to be damped, and will come to rest in a few seconds.
History
More information about Magnetic Levitation
In literary English, Levitation means the process of rising or being raised in the air. Science defines Levitation as "the equilibrium of a body without solid or liquid contact with earth"; Levitation can be achieved using electric or magnetic forces.
The discovery of High Temperature Superconductors are one of the most important and fascinating event in Science and Engineering. This ignited public imagination about Levitated Motion. The Japanese demonstrated a Magnetic Levitation Train at a phenomenal speed of 500km/Hr., how this was possible?
The fascinating qualities of superconducting levitation is to achieve relative velocity of 100-200m/sec. among moving bodies with no contact, no wear, no need for fluid or gas intervention and no need for active controls.
The salient features of superconducting materials that are relevant to Levitation are:
1. Zero Resistance to steady current flow.
2. Exclusions of magnetic flux lines at low fields
3. Flux trapping or spinning at higher magnetic fields.
Zero resistance is crucial in creating large magnetic fields in multiple turn coil magnets and is essential to the induction of super currents in passive bulk levitation magnetic bearings.
Complete or partial flux exclusion is necessary for repulsive levitation bearings.
Flux pinning or trapping is important for producing materials bulk levitation phenomenon that creates suspension forces.
Magnetic Levitation requires two necessary sub-systems:
1. A primary system for generating the magnetic field.
2. A system for shaping or trapping the magnetic field.
For electric-magnetic levitation, electric currents in a wire wound coil produces the primary field, while the Ferrite-magnetic coil holder and the ferrite-magnetic base creates a means of shaping the magnetic filed.
Levitation technology is a vast and complicated subject. I have only tried to create some interest to the readers so that they will try to know further about this wonderful subject. By reading this Article, if anyone is interested to know further, he is welcome to contact this technical writer to get further information.
How can you magnetically levitate objects?
Magnetism is fascinating, especially when it is used to cause objects to levitate or float or be suspended in the air, defying the gravity, which keeps us on the ground. How can this be done? There are 10 ways to magnetically levitate objects:
MAGLEV Methods
1. Repulsion between like poles of permanent magnets or electromagnets. However, there needs to be a way to constrain the magnets so they don't flip over and become attracted to each other. For example, floating donut magnets have the dowel rod in the center to keep them from flipping over.
2. Repulsion between a magnet and a metallic conductor induced by relative motion. However, the magnet needs to be restrained from moving in the same direction as the conductor, otherwise it will travel with the conductor.
3. Repulsion between a metallic conductor and an AC electromagnet. It is possible to shape the magnetic field to keep the conductor constrained in its motions; otherwise, a mechanical means is needed to keep the conductor in place.
4. Repulsion between a magnetic field and a diamagnetic substance. This is the case of the floating frog, and the floating magnet between two diamagnetic disks.
5. Repulsion between a magnet and a superconductor. No mechanical constraints are needed for this.
7. Attraction between the open core of an electromagnetic solenoid and a piece of iron or a magnet. The iron or magnet will touch the inside surface of the solenoid.
8. Attraction between a permanent magnet or electromagnet and a piece of iron. Again, the iron needs to be constrained.
9. Attraction between an electromagnet and a piece of iron or a magnet, with sensors and active control of the current to the electromagnet used to maintain some distance between them.
10. Repulsion between and electromagnet and a magnet, with sensors and active control of the current to the electromagnet used to maintain some distance between them.
Difficulties:
Most of the levitation techniques have various complexities.
Sources:
1. http://en.wikipedia.org/wiki/Magnetic_levitation
2. http://hyperphysics.phy-astr.gsu.edu/hbase/solids/maglev.html
