1. Magnetic Energy Density:
Magnetic energy density is one of the key properties of materials. It represents the ability of a magnet to store much magnetic energy, usually expressed in terms of magnetic energy per unit volume. Materials with high magnetic energy density can generate a stronger magnetic field in a limited space, thereby improving the output torque and performance of the motor. Common high magnetic energy density materials include neodymium iron boron (NdFeB) and cobalt magnets (SmCo). These materials are widely used in high-performance servo motors because of their ability to achieve excellent power density.
2. Saturation Magnetization:
Saturation magnetization indicates the maximum magnetization of a material in a saturated state. A high saturation magnetization means that a material can achieve a higher magnetic induction for a given magnetic field. This is critical to improving the performance of the motor as it enables the motor to operate at a higher duty point, resulting in higher torque and efficiency. NdFeB is a commonly used magnet material with high saturation magnetization.
Remanent magnetization is the permanent magnetization that remains in a material after the external magnetic field is removed. The residual magnetization of the material has an important influence on the control performance and response speed of the motor. Materials with low residual magnetization demagnetize faster and are therefore useful in servo motors that need to switch the direction of the magnetic field frequently. This helps improve the accuracy of the motor, especially in applications that require precise position control.
Coercivity is the strength of an external magnetic field required for a material to return to its unmagnetized state. Materials with high coercivity are very useful for resisting interference from external magnetic fields, which can improve the anti-interference and stability of servo motors. This is critical in applications that require high precision and reliability, such as industrial automation and robotics.
5. Temperature Stability:
The temperature stability of the material is critical to the performance of the servo motor at different operating temperatures. Some materials may lose their magnetism at high temperatures, while others are more temperature stable. Servo motors operating in high temperature environments require the selection of magnet materials with good temperature stability to ensure that performance is not affected by temperature changes.
6. Cost and Processability:
Cost and processability are another important factor to consider. High-performance magnet materials can be expensive and difficult to process, while other materials can be more affordable and easy to process. When selecting materials, a combination of performance and cost factors need to be considered to ensure that the overall cost of the motor is acceptable.