Why use Arc Shaped Magnet on BLDC Motor?
Arc shaped magnets used on C4 & C5 Motors:
1. What is Arc shaped Magnet ?
Arc shaped magnets are also called tile shaped magnet, curved magnet, their shape curved like tile, is commonly used in brushless motors, generators and torque couplings due to the configuration of their north and south polarities. The shape is cylinder-like, with a slight curve to their body, making them ideal for cylinder-like materials and piping. Neodymium magnets are much stronger than other magnets, using neodymium arc magnet can build stronge forces and power in the items they inhabit, the material Maytech use is Neodymium arc magnet in their C4 & C5 motor.
Neodymium arc magnets are also called Arc segment magnets, which are made by wire cutting of the block magnets. This type of segment magnets are commonly used in DC motors, both for rotors and stators.and other motors.
2. What other shaped magnets are also used in motor?
For brushless motor, commonly used magnet also have rectangular shaped (flat magnet, straight magnet), double arced shape magnets.
The air gap of the arc shaped magnetic steel is uniform, while the rectangular shaped magnet air gap is not uniform, so arc shaped magnet will allow you to get the magnets closer to the ends of the stator (decreasing air gap) and in doing this increase the flux between them.
All other factors being equal (windings, stator, magnets, airgap, flux ring), the motor with curved magnets will be more powerful than the flat magnet motor.
3. Why arc shaped magnet is better?
As above mentioned, with arc shaped magnet could decrease air gap when stick magnet to stator, and increasing flux between them, their shape allows for a unique electrical flow of power continuing to drive their usefulness in motor-like items.
Except for that, with arc shaped magnet, when motor runs at high speed, would produce less airflow vibrations and motor variation, more stable and higher efficiency, better performance on BLDC motor.
There is no doubt that the curved magnets are better suited for these brushless outrunner dc motors. Also the curved magnet motor will produce more torque for a given amperage.
Here are also other arc shaped magnets, the one Maytech used in C4 & C5 motor is curved botth arc type