A permanent magnet can be produced in various forms. These shapes can exert a great influence on the magnetic properties of a permanent magnet. So also with the ring magnet. Through a round hole, tubular magnets are created, which have special magnetic fields and modes of action due to their ring shape.
What shapes of ring magnets are there?
Ring magnets can be diametrically, axially, or radially magnetized:
Diametrical means that the two magnetic poles are aligned parallel to the diameter. Because of limited use, diametrical ring magnets are rarely used.
Axial means that the two magnetic poles are on the top and bottom of the flat circular surfaces. Axial ring magnets are the most commonly used form of magnet rings.
Radial means that the poles extend to an inner circle (adjacent to the hole) and an outer circle. The production of special radial magnetic rings proves to be extremely complicated and expensive.
Ring magnets can be made of ferrite or neodymium or NdFeB (neodymium-iron-boron) and, like most magnets, have a nickel-plated coating to protect against oxidation. On the basis of their outside and inside diameters as well as the height they can be characterized more accurately and give information about adhesion, strength, and co.
Regardless of the orientation, care should always be taken when using ring magnets, as their separate shape creates a greater risk of breakage. For example, ring magnets can break or splinter quickly when screwed on, as the brittle material can not resist enough. Ring magnets with countersunk holes can be an alternative here.
Applications of Ring Magnets
Because ring magnets have special magnetic field lines, they are often used in physics lessons in schools or at universities. An application of ring magnets: The identification of the magnetic levitation (free-floating of a body). For this purpose, two axially magnetized ring magnets are placed on a vertical holder (for example a pin). By repelling the opposite poles, the upper ring magnet begins to float. Because the charges repel each other so much, gravity can be balanced.