In radial flux applications, a Neodymium arc magnet typically has a uniform arc or specialized profiles to enhance magnetic performance, especially in surface-mounted PMSMs. With diametrical magnetization perpendicular to the rotation axis, these magnets suit radial flux systems, including conventional motors, generators, and magnetic couplings.
Neodymium magnets encounter challenges in achieving precise shapes and dimensions during pressing under an external magnetic field, complicating direct production to meet application needs. Consequently, additional machining of sintered blanks is required to ensure the final Neodymium arc magnet aligns with desired specifications.
Machining these sintered blanks into the Neodymium arc magnets involves techniques more intricate than those for standard shapes like cylinders, rectangles, or rings. Typically, the machining process for Neodymium arc magnets employs either wire-cutting or profile (contour) grinding methods.
Single-wire cutting excels in crafting specially shaped magnets due to its versatility, though it faces criticism for low efficiency and higher costs. Multi-wire cutting has resolved these drawbacks, proving effective for larger batches of arc magnets with lower bows and higher spans, enhancing production efficiency.
Despite this, single-wire cutting is favored for deeply curved arc magnets, prototypes, and small batches of varied shapes. Conversely, profile grinding provides efficiency and cost benefits but struggles with complex dimensions, limiting its versatility.
Neodymium arc magnets are magnetized in varying directions based on their use in radial or axial flux systems. In radial flux setups, a Neodymium arc magnet typically undergoes diametrical magnetization and is often paired to establish the necessary magnetic flux distribution. Notably, producing a purely radially magnetized Neodymium arc magnet poses significant manufacturing challenges.
Fan-shaped arc magnets are frequently utilized in axial flux systems due to their compatibility with axial magnetization. Moreover, in both axial and radial flux Halbach arrays, combining chord-magnetized magnets with standard axial or diametrical magnetization enhances magnetic flux density and distribution, optimizing system performance effectively.
A Neodymium arc magnet is vital in motor applications, where its geometry and magnetic performance significantly enhance motor efficiency. Beyond basic magnetic properties and coatings, the shape of a Neodymium arc magnet is crucial for improving performance. Slotted motors often experience cogging torque from magnet-stator teeth interactions, causing torque ripple, vibration, and noise that reduce smoothness and efficiency. To counter this, arc magnets in radial or axial flux motors are frequently designed with skewed shapes, minimizing cogging for smoother operation and better overall performance.
Another challenge in motor design is eddy current loss, generating heat that raises temperatures and risks demagnetization, thus lowering efficiency. Laminated arc magnets, made of thin bonded layers, are increasingly adopted to tackle this. This Neodymium arc magnet design reduces eddy current losses without altering the motor’s structure, boosting efficiency and thermal stability.
