China Neodymium And Ferrite Magnets Manufacturer & Supplier 
In products such as electric motors and encoders, Hall magnetic rings and spindle magnetic rings are frequently mentioned. Some internet users have asked whether these two types of magnetic rings are the same. Below, Xiao Fu from Dongguan magnet manufacturer NST will provide an explanation.
Although Hall magnetic rings and spindle magnetic rings both utilise changes in the magnetic field to perform detection or control, they are not entirely the same.
Hall magnetic rings are primarily used in conjunction with Hall sensors for position and speed detection; they enable the sensor to recognise the rotational state of the rotor through changes in the magnetic poles. Spindle magnetic rings, on the other hand, are magnetic components typically mounted on the motor spindle or rotor; their main function is to generate the driving force required to rotate the motor.
Injection-moulded magnetic rings for Hall sensors
They also have different requirements in terms of magnetic performance. For example, spindle magnetic rings generally require higher magnetic performance; in brushless motors in particular, sintered neodymium-iron-boron magnets and bonded neodymium-iron-boron magnets are commonly used. Hall effect magnetic rings, on the other hand, focus more on the number of magnetic poles and the uniformity of the magnetic field. Common configurations include 2-pole, 4-pole, 8-pole, 12-pole, 24-pole and even higher pole counts, primarily to ensure that the Hall effect sensor can accurately detect angle and rotational speed; the materials used are predominantly sintered ferrite and injection-moulded ferrite.
However, in some small motors, encoders, power tools and smart devices, the Hall sensor ring and the spindle magnet ring may be designed as part of the same rotating assembly; for example, a main magnet may be installed inside the motor rotor, whilst a small multi-pole magnet ring is added at the tail end for Hall detection. This not only saves space but also improves control accuracy; however, the functions performed by the two remain distinct.
Therefore, one should not simply assume that Hall rings and spindle rings are identical; their primary materials, number of magnetic poles and functions will all differ.
Other articles on Hall magnetic rings;
Radially Magnetized Magnetic Ring For Hall Limit
Is there a right or wrong side for the magnet of the hall sensor?