What is a Ring Magnet? Definition, Characteristics and Uses

Ring magnets definition

A ring magnet is a type of permanent magnet with a circular shape and a hole in the center. It is made from various magnetic materials, such as neodymium iron boron, ferrite, and samarium cobalt. Ring magnets are available in a wide range of sizes, strengths, and magnetization directions, making them suitable for various applications.

Ring magnes structure

A ring magnet typically consists of the following parts:

Outer diameter: The diameter of the ring magnet.
Inner diameter: The diameter of the center hole of the ring magnet.
Thickness: The thickness of the ring magnet.
Magnetization direction: The direction of the magnetic field in the ring magnet.

Ring magnets materials

Ring magnets can be made from various magnetic materials, each with its own unique properties and advantages:

Neodymium iron boron (NdFeB): The strongest magnetic material, but it is also the most susceptible to corrosion and requires surface treatment.
Ferrite: Lower cost, but weaker magnetic force, suitable for low-cost applications.
Samarium cobalt (SmCo): High coercivity, high temperature and corrosion resistance, but expensive.

Ring magnets characteristics

Ring magnets have the following main characteristics:

Magnetic force: The strength of the magnetic field of the ring magnet, measured in gauss or tesla. Usually represented by surface magnetic field (Br) or magnetic flux density (B).
Coercivity: The ability of the ring magnet to resist demagnetization by an external magnetic field. Unit is oersted.
Remanence: The magnetic field remaining in the ring magnet after the external magnetic field is removed. Unit is gauss or tesla.
Working temperature: The temperature range at which the ring magnet can operate normally.

Ring magnets applications

Case Study 1:

Application: Electric motors

Product used: D43-D34-6 neodymium ring magnet

Product specifications: Outer diameter 43 mm, inner diameter 34 mm, thickness 6 mm, material: neodymium iron boron

Case description:

This neodymium ring magnet is used in a small electric motor as the magnetic material of the rotor. It features high magnetic force, high efficiency, and low noise, effectively improving the performance of the motor.

Case Study 2:

Application: Sensors

Product used: D63-D34x5 neodymium ring magnet

Product specifications: Outer diameter 63 mm, inner diameter 34 mm, thickness 5 mm, material: neodymium iron boron

Case description:

This neodymium ring magnet is used in a Hall sensor as a magnetic field sensing element. It can accurately detect the movement and position of objects and is applied in industrial control, automotive electronics, and other fields.

Case Study 3:

Application: Medical devices

Product used: D88-D75x3 neodymium ring magnet

Product specifications: Outer diameter 88 mm, inner diameter 75 mm, thickness 3 mm, material: neodymium iron boron
Case description:This D88-D75x3 NdFeB ring magnet is used in MRI equipment to generate strong magnetic fields. It improves image quality, reduces scan time, and makes equipment more compact.

Conclusion

Ring magnets, with their unique shape and magnetic properties, play a crucial role in diverse fields. The three case studies demonstrate their applications in motors, sensors, and medical devices, each highlighting different considerations for choosing the right ring magnet. When selecting a ring magnet, comprehensively assess your application needs, material characteristics, size & strength, and magnetization direction to achieve optimal results.