Magnetic Ring Types for Magnetic Encoders

The magnetic ring materials used for detection in magnetic encoders typically include ferrite (sintered/injection-molded/rubber) and neodymium (injection-molded/bonded). Magnetic ring types can be categorized as single-pole magnetic rings, multi-pole magnetic rings, multi-pole dual-track magnetic rings (for absolute position encoding), and non-uniformly magnetized magnetic rings (for complex encoding applications). Below is an introduction to the characteristics and applications of these magnetic ring types.

Single Pair Pole Magnetic Ring

This magnetic ring features a single magnetic pole pair, i.e., two poles. By placing two linear Hall sensors at a 90° angular offset within the magnetic field, a pair of orthogonal waveforms can be obtained. The unique angular position can be calculated using the inverse tangent function arctan(y1, y2).

Applications: Motor Hall sensors, magnetic encoders.

Multi Pair Pole Magnetic Ring

A circular magnet with 2 or more pairs of magnetic poles, such as a 64 pole planar magnetized magnetic ring containing 32 pairs of magnetic poles. When it rotates, the Hall sensor outputs 32 complete sine wave cycles, which is commonly used in incremental encoders.

Multi-pair pole ring-shaped rubber ferrite magnets for encoders

Multi Pair Pole Dual Code Track Magnetic Ring

Multi pole dual code track magnetic ring is a type of magnetic ring with two independent magnetic pole arrangement trajectories, widely used to improve the resolution and anti-interference ability of magnetic encoders, and provide more accurate position information. Due to the difference in pole pairs, the combination of inner and outer magnetic fields at any angle position is unique, thus achieving high-resolution absolute positioning. Similar to the "Gray code" in optical encoders.

Irregularly Magnetized Magnetic Rings

Non-regular magnetized magnetic rings are relatively less common in encoders, yet they offer unique advantages in specific applications, particularly where high resolution and specialized performance requirements are needed. Unlike conventional regular magnetized magnetic rings, the magnetic field distribution in non-regular magnetized rings does not follow standard symmetrical or regular layouts. This magnetization method can optimize encoder performance by altering the arrangement of magnetic poles.

Applications: High-end servo systems, medical equipment, spacecraft attitude control, etc.

The above covers the four types of magnetic rings used in magnetic encoders. For pricing or samples, please provide the dimensions, magnetic pole requirements, surface flux density, and other relevant specifications.

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128 poles and 126-poles multipole magnetic encoder ring magnets

Magnetic encoder multipole ring magnet 62 pole 64 pole OD 34mm