We supply custom 4-pole Neodymium ring magnets with alternating North-South-North-South zones in 90° segments. The poles can be arranged on the flat face (axial) or around the circumference (radial). Why 4-pole specifically: In rotary encoders, 4 poles provide 4 pulses per revolution. Enough for basic position detection while maintaining strong field strength per pole. In brushless motors, 4-pole configurations allow 2-phase or 3-phase coil arrangements in compact diameters. While 6-pole or 8-pole segmentation would make individual poles too small to produce adequate flux. Primary applications: – Rotary position sensors – Hall effect or magnetoresistive sensors detect the alternating field, providing quadrature signals for direction sensing – Compact brushless motors – 4-pole radial rings in small-diameter motors (under 30mm OD) where higher pole counts reduce per-pole strength – Magnetic couplings – 90° pole spacing allows torque transmission with self-centering alignment We can produce these by assembling four pre-magnetized wedge segments (each 90°) and bonding them into a ring. And, we can also magnetize a single sintered ring using a 4-pole fixture. Provide your OD, ID, thickness, pole orientation (axial or radial), and expected quantity. The 4-Pole Advantage: “Twist & Lock” This is a unique application for 4-pole Axial rings that doesn’t apply to 8-pole rings. Smart Mechanical Integration: The 4-Pole Axial configuration (Face Magnetized) is the industry standard for Magnetic Twist-Locks. How it works: – When you mate two 4-pole rings together, they attract strongly in the aligned position. – If you rotate one ring by 90 degrees, the poles repel. Application: – This allows for “Quick-Release” mounts (e.g., phone mounts, camera fixtures, or headphone cables) that lock securely. – Meanwhile, release with a simple quarter-turn twist. Magnetization Patterns Clarify the difference between motor use and sensor use. 1. Axial 4-Pole (Face Magnetized) Pattern: The flat face is divided into 4 “pizza slices” (90° each). Best For: – Twist-lock mounts, Hall effect sensors requiring 2 pulses per revolution. – And hold against thinner steel (where 2-pole flux would waste energy passing through). 2. Radial 4-Pole (OD/ID Magnetized) Pattern: 4 Poles alternating around the outer or inner circumference. Best For: – High-Speed BLDC Motors. – A 4-pole rotor is capable of higher RPMs than an 8-pole rotor. – Because the switching frequency (commutation) is lower, reducing eddy current losses. Manufacturing Options (The Trader Solution) Monolithic (Pulse Magnetized): – A solid single ring magnetized with a specialized 4-pole fixture. – Best for: Small rings (< 50mm) and high-volume production. Segmented Assembly (The “bread-loaf” method): – Instead of a solid ring, we glue 4 separate Arc Segments (90° each) onto a steel hub. – Best for: Large motor rotors (> 50mm). Or, prototypes where building a custom magnetizing fixture is too expensive. Applications Consumer Electronics: “Twist-Lock” mounts for action cameras and smartphones. Motors: 4-Pole Brushless DC (BLDC) motor rotors (common in drones and power tools). Sensors: Speed sensing where 2 pulses per revolution are required. Couplings: High-torque magnetic couplers for mixing equipment. Ordering Guide To ensure compatibility, please specify: 1). Dimensions: OD x ID x Thickness. 2). Orientation: Axial (Face) or Radial (Edge)? 3). Application: – Motor: We will focus on high-temp grades (UH/EH). – Holding/Locking: We will focus on N50/N52 for max force. 4). Construction: – Do you need a solid ring, or can we supply 4 glued arc segments? – Segments are often cheaper for large sizes.