What is a Ring Magnet?

The ring magnets are disc magnets with a hollow centre and the distribution of poles is determined by the direction of magnetisation. Ring magnets are highly practical and replace the need for traditional ring magnets to be glued in place (e.g. on motor rotors, solving the disadvantages of being made to be unmanageable and increasing the maximum torque) to great advantage.

Ring magnet field：

The Applications of Ring Magnet

The ring magnets are very versatile and are commonly used in scientific experiments, as well as in magnetic levitation, motors, electroacoustics, salvage, medicine, instrumentation, craft jewellery, leather handbags, packaging boxes, toys, etc.

The Ring Magnet For Electrical Machinery

The performance of ring sintered NdFeB magnets is superior to bonded NdFeB magnets and injection moulded ferrite rings. Toroidal magnets are commonly used in electric motors, where bonded NdFeB magnets and injection moulded ferrite rings are used. These magnets have the advantage of being low cost and easy to assemble. The general speed is around 5000 rpm and the magnets do not need to be protected on the outside. In contrast, ring sintered NdFeB magnets require special moulds for production and magnetisation, which is more costly. In addition, the various magnetisation methods can produce a better sinusoidal magnetic field and are more reliable than conventional ones for high-speed motor applications.

Ring magnet levitation：

The centre of the ring magnet is empty and when a small magnet is held close to the central hollow of the ring magnet, it can feel the repulsive force, whereas it can feel the attractive force at the edge of the ring magnet.This is because although the ring magnet is south pole up, in the central hollow part of the ring magnet the magnetic lines of force are oriented similarly to those emanating from a small magnet with the north pole upwards.Thus, in magnetic levitation, why ring magnets are used, when two solid magnets are in close proximity to each other, we feel not only repulsion but also 'torque', i.e. the magnets try to flip to opposites and attract each other.However, when a small solid magnet is close to a large ring magnet, only the repulsive force is felt, not the 'torque'. This makes magnetic levitation much less of a problem, as we only need to control the magnet from slipping to the side, rather than worrying about it flipping over.

How to Distinguish the Polarity of Ring Magnet? 

1.The easiest way to identify the magnetic poles is to put the ring magnet into fine iron filings, and the two positions that attract the most iron filings are the poles. In addition, you can use a block of iron to draw the magnet up from above, allowing the magnet to sag naturally, with the poles at the point of contact with the iron and relative to each other.

2.Determine the north and south poles by placing the poles of the magnet horizontally on a smooth horizontal surface, or by bagging the magnet and suspending it with a thin rope, so that the poles of the magnet are roughly horizontal, then the pole pointing north at rest is the north pole and the pole pointing south at rest is the south pole.

3.If a magnet with known north and south poles is available, so it is simple to use the magnet to suck the spherical magnet up from the top so that the spherical magnet drops naturally, the two magnets touching will be the opposite pole and the other side of the spherical magnet will be the other pole.