Where does the loss of Motor Magnets come from during the operation of the motor?
Publish Time: 2024-08-09
There will be certain losses in Motor Magnets during the operation of the motor, and its main sources are multiple.
The first is hysteresis loss. When Motor Magnets are placed in an alternating magnetic field, the magnetic domains inside them will constantly change direction to adapt to the changes in the magnetic field. In this process, the friction of the domain wall and the rotation of the domain itself will consume energy, resulting in hysteresis loss. Moreover, hysteresis loss is related to the frequency of magnetic field change and the hysteresis loop area of the magnet material. The higher the frequency, the larger the hysteresis loop area, and the greater the hysteresis loss. For example, in some high-frequency motors, hysteresis loss may be more significant, affecting the efficiency of the motor.
The second is eddy current loss. When Motor Magnets are in a changing magnetic field, according to the principle of electromagnetic induction, an induced electromotive force will be generated inside the magnet, which will cause eddy currents. These eddy currents will generate Joule heat when flowing inside the magnet, resulting in energy loss. Factors such as the resistivity, thickness, and rate of change of the magnetic field of the magnet will affect eddy current loss. Generally speaking, eddy current loss can be reduced by using high resistivity materials or dividing the magnets into thin slices.
In addition, there is also the effect of temperature on the loss of Motor Magnets. As the operating temperature of the motor increases, the magnetism of the magnet may change, resulting in a decrease in its performance and an increase in loss. For example, excessively high temperatures may cause partial demagnetization of the magnet, affecting the strength and stability of the magnetic field, and further affecting the operating efficiency and performance of the motor. At the same time, temperature changes may also cause thermal expansion of the magnet, change its assembly state in the motor, and indirectly affect the operation of the motor. In addition, factors such as mechanical stress during the operation of the motor may also cause a certain degree of damage to the Motor Magnets, resulting in increased losses. For example, long-term vibration may cause tiny cracks inside the magnet, affecting its magnetic properties. In summary, understanding these sources of Motor Magnets loss is of great significance for reducing losses and improving motor efficiency and performance.
