# Magnetic suspension

What is a magnetic suspension? To hang massive objects you need a magnetic field of monstrous tension. In 1939, the German scientist W. Braunbek used an electromagnet for this, otherwise he would not be able to obtain such a high magnetic field strength with the help of permanent magnets of the time. But the electromagnet required constant current make-up. From the energy point of view, it turned out that a gluttonous electromagnet capable of lifting tons, raises milligrams.

In 1956, the magnetic suspension turned out to the Dutch scientist A. Boerdick. He carried out a non-contact suspension, and without the consumption of electricity. The experience of Boerdick consists in the following: above the hemisphere of a strong diamagnetic - graphite, a cylindrical permanent magnet is vertically mounted. And in the gap between them put a small, about 2 milligrams of weight, a magnet in the form of a microscopic washer the size of a pinhead. The magnet is magnetized so that one end of it is the North Pole, the other is the South Pole. At the same time, the magnet hung in this gap.

How does such a magnetic suspension work? On the one hand, the diamagnetic graphite tries to push away from itself a magnetic washer. But the ice-ball, even if the forces of the diamagnet were enough for this, would still fall or turn sideways. The diamagnet did not calculate it - it simply provides the magnet with the necessary help to just tear off the magnetic washer from its surface. In addition, the magnet centers this shaibochku, does not allow it to turn on its side or on the edge.

The force of magnetic attraction is not enough to tear the object from any surface and to lighten it to him at lightning speed. They are sufficient only to use a diamagnet to slightly raise the washer, after which the force of diamagnetic repulsion of graphite will decrease sharply. Here is a magnetic suspension from a magnetic washer and hangs, not being able neither to fall on the graphite, nor to be attracted to the pole of the magnet.

A real breakthrough was made by the German scientist E. Steingrover. Its magnetic suspension was literally Hercules in comparison with the Braunbek and Boerdick suspension brackets. Magnetic suspension Steingrover, using the properties of both ferromagnets and diamagnets, allowed to hang the disk in an exact electrical appliance weighing as much as 50 grams! This is 1000 times more than it was possible before.

The main gravity in the magnetic suspension of Steingrover "holds" a permanent annular magnet, which centers small cylindrical magnets and pulls them upwards. But since such a position is unstable, the axis of the disc on which these pins are inserted immediately should pop up or down. The inventor has designed it so that it tends slightly downward. But here the axis supports a diamagnetic bearing in the form of a graphite ring, repelled from a strong permanent magnet. And repulsion is something small - only 0,04 N, but this is enough to make the magnetic suspension stable.