China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Although fan motors appear to be simple in design, the magnetic rings inside are in fact key components that influence the motor’s performance. This is particularly true for modern products such as brushless fans, ceiling fans and air circulators, where demands on motor efficiency, noise levels and rotational speed stability are becoming increasingly stringent; the material, dimensions and magnetisation method of the magnetic rings all have a direct impact on the motor’s performance.
At present, there are two main materials commonly used for magnetic rings in fan motors: injection-moulded ferrite and bonded neodymium-iron-boron. Each material has its own characteristics, and customers should select the appropriate one based on the motor design, cost considerations and performance requirements.
Below is a selection of injection-moulded ferrite magnetic rings produced by our company for use in fan motors; these are primarily used in standard brushless fan motors.
D58 × d53 × 14 mm, 10-pole internal magnetisation
D56 × d49.5 × 15 mm, 10-pole internal magnetisation
D55.9 × d53.2 × 14 mm, 10-pole external magnetisation
D59 × d53 × 14 mm, 10-pole internal magnetisation
D65.5 × d57.5 × 20 mm, 10-pole internal magnetisation
D80 × d66 × 50 mm, 8-pole internal magnetisation
The following is bonded neodymium-iron-boron material, which offers greater magnetic strength and is suitable for high-performance fan motors.
D28*d24*10mm, with an inner diameter magnetized to 12 poles, and a surface magnetic field strength of 2700Gs
D27*d22.7*21mm, with an inner diameter magnetized to 10 poles, and a surface magnetic field of 1841Gs
D44.6*d39.8*6.8mm, inner diameter magnetized with 16 poles, surface magnetism 2100Gs
D36*d31.6*15mm, with an inner diameter magnetized to 10 poles
D32.8*d28.6*5mm, with an inner diameter of 14 poles and a surface magnetism of 2300Gs
D59*d53*22mm, with an inner diameter magnetized to 10 poles
D27*d24.4*7mm, with an inner diameter magnetized to 12 poles
D45.9*d41.3*20mm, with an inner diameter magnetized to 10 poles
D56*d53*14mm, with an inner diameter magnetized to 10 poles
D50*d44*20mm, with an inner diameter magnetized 8 poles
In addition to magnetic rings, some fan motors utilise arc-shaped magnets made of sintered ferrite. You can view and select the relevant dimensions by clicking on the ‘Arc Shaped Ferrite Magnet Mold Dimensions for Fan Motors’.