Powering Precision: The Essential Role of Magnets in Servo Motor Technology
Discover the critical role that magnets play in servo motor technology, enabling precise control, efficient performance, and exceptional reliability across a myriad of applications in robotics, automation, and beyond.
Definition of servo motor magnet
Servo motor magnet is named according to the specific magnet application of servo motors. Servo motor applications are mostly commonly used in closed loop systems, where precise position control is commonly found in industrial and commercial applications. The servo motor utilizes a regular permanent magnet motor and couples it with a hall sensor for positional feedback.
According to the specific design of the servo motor rotor assembly, two different shapes of neodymium magnets are utilized. They are neodymium arc magnet and rectangular neodymium magnets. Nickel and epoxy are two most common coating types used in servo motor applications. Both coating options provide good corrosion resistance and adhesive effect.

Considerations on choosing servo motor magnet
Another important consideration when choosing servo motor magnet is the maximum operating temperature of the designated servo motor. Engineers should be aware of the maximum temperature that the rotor magnets may experience in the extreme operating condition. Because neodymium magnets will demagnetize at certain temperature depending on the coercivity (coercive force Hcj). Common neodymium magnet grades for servo motor application are N33UH, N35SH, N35UH, N38SH, N38UH, N42UH, etc.
Types of servo motor magnets
Different neodymium magnets can be used for servo motors, but not all are created equal. Sintered neodymium magnets deliver more power in less space compared to bonded neodymium ring magnets. However, bonded neodymium magnets are compression molded and classified as isotropic magnets, making them more versatile in terms of shapes and magnetization patterns.
Multipole ring magnets, which can be divided into radially magnetized ring magnets and polar-anisotropic ring magnets, also offer an alternative for servo motor magnets. These magnets provide additional flexibility and customization options, further broadening the range of potential magnet solutions for servo motor applications.
