How to judge that the magnet is demagnetized.
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How to judge that the magnet is demagnetized

Magnet is an important part of the motor, which is mainly used to generate a magnetic field to drive the motor to rotate. When we use the motor, we often find that the rotation speed is abnormal, and sometimes there will be idling. If other external factors are eliminated, it may be the problem of the magnet, which is the demagnetization of the magnet. If the magnet is demagnetized, the magnetic field will be weakened, the motor will be idling, and the power consumption will increase. The magnetic material manufacturer will show you how to identify whether the magnet is demagnetized.
1. Obviously, the motor speed is much faster than normal, and the no-load current also becomes larger.
2. It is enough to directly measure the magnetic field center density with a Tesla meter; if the motor is demagnetized, the no-load speed will increase, the load current will increase, and the braking torque will decrease.
3. If you have more than two motors in your hand, test the no-load rotation speed for comparison. If the motor has demagnetization, the no-load speed will increase a lot, and sometimes it can be compared by listening to the rotating sound of the motor. Or fold the motor suspected of demagnetization and compare it with a good motor to find out the Gaussian magnetic field center point of the magnet.
4. It can be judged by looking at the no-load speed and current, the current becomes larger after demagnetization. The speed becomes higher.
5. Measure the induced voltage at the same speed. If the voltage becomes smaller, it is demagnetization.
6. If it is a tile-shaped magnet, analyze and test the Gauss value on the left and right sides for comparison. If there is a large difference, it has been demagnetized!
The above six methods are the identification methods of magnetic steel demagnetization. Have you learned it? If you find that the motor is abnormal, you can try to identify it, repair it as soon as possible, and restore the normal operation of the motor.