What is electromagnetic levitation? What is it used for?
Have you ever heard of Maglev trains in Japan, or Transrapids in Europe? Are you familiar with magnetic levitation trains? These are trains that "levitate" on the rails thanks to a magnet field. In order to learn more, find in this article everything you need to know about electromagnetic levitation and its role in the world around us. Also find our collection of Magnetic Globe that uses this same energy.
Understanding electromagnetic levitation
In physics and science, there are two fundamental concepts about the principle of levitation: the electromagnetic concept which is generated by regulated electromagnets and the electrodynamic concept which is based on the forces of induced currents. Electromagnetic levitation is defined as a mechanism for levitating an object using a magnetic field. The electromagnetic forces exerted on this object allow it to oppose its own weight and float without falling.
More concretely, an object is in a state of electromagnetic levitation when it floats above a magnet support without contact with that support. A vertical force directed from bottom to top balances the weight of this object/body. Transrapid trains in Germany or Shanghai are concrete examples of electromagnetic levitation. On the other hand, Japanese Maglev trains use electrodynamic levitation.
How does electromagnetic levitation work?
Electromagnetic levitation is feasible due to magnetic forces. To understand this, you already need to know how magnets work. It is very simple! Let's start with the principle that a magnet can attract or repel ferromagnetic materials depending on the positioning of the poles. North and North poles attract each other and North and South poles repel each other.
The magnetic mechanism occurs when the magnets are activated alternately (attract and repel each other). The gravity acting on the levitating object is offset by these forces. This allows to maintain a constant distance between the object and the ground, avoiding friction. This frictionless mechanism, by the way, makes it possible to move faster. To activate the levitation or electromagnetic levitation system, electromagnets and superconductors are used.
An electromagnet is a magnet powered by electric current. It is used to convert electrical energy into magnetic energy. To do this, the magnet consists of a magnetic iron core surrounded by a coil of conducting wire. The magnetic field is then produced during the passage of the electric current over the electromagnet. Due to this principle, the electromagnet has an intense mechanical force of attraction. This is the reason why it is used in electromagnetic levitation.
Superconductors are materials that are able to conduct electric current perfectly without resistance or energy loss. This is the phenomenon of superconductivity. This is made possible by cooling the material to rid it of all electrical resistance.
Discovered by Dutch physicist Heike Kamerlingh Onnes in 1911, the phenomenon of superconductivity still remains an exceptional discovery. Especially since superconductors also have exceptional magnetic properties. They can levitate without any problem under a magnet.
What is electromagnetic levitation used for?
As you may have already noticed above, electromagnetic levitation makes it possible to levitate an objectt on a magnetized surface, without them touching. But in addition, this mechanism also makes the moving object faster. This is the reason why the main application of electromagnetic levitation is in the railway field, especially for the propulsion and levitation of trains like the German Transrapid or the Shanghai Transrapid.
The electromagnetically levitated train
The electromagnetically levitated train levitates solely by pole attraction. To do this, it is designed with electromagnets placed on the bottom, parallel to the rails. The rails, too, have laminated iron bars that will come into contact with the electromagnets.
An electromagnetic field then occurs without the electromagnets and iron bars making contact. But in addition, the train goes into levitation (i.e., it does not land on the rails). It propels itself at a maximum speed of up to 150 km/h.
The advantages of electromagnetically levitated trains
If today the electromagnetic levitation is highly developed in trains, it is mainly because it has several advantages:
- This mechanism allows trains to travel at high speeds.
- It also reduces the noise pollution caused by the passage of trains on the rails (since the levitating train will not touch the rails).
- It is a clean and less polluting system: the electromagnetic levitation train does not emit smoke and uses few energy resources. Little rejection and electrical loss thanks to superconductors.
- The aerodynamic resistance and speed of trains do not cause damage to the ecosystem.
On the other hand, the implementation of this concept is still very expensive. For this reason, there are very few electromagnetically levitated trains in the world.