What happens to a neodymium magnet when it’s energized? Will it cause demagnetization?
A strong magnet (NdFeB) can conduct electricity, which is the highest of all permanent magnets. One might ask, what happens when a neodymium magnet is electrified? Will it demagnetize?
If a neodymium magnet is applied to a direct current, a circular magnetic field is created. In general, the current is small and has little effect on the magnetic field of the permanent magnet itself. It is simply estimated that when the current in a DC wire is 1 Amperes, the magnetic field intensity generated at 1 mm away from the wire is about 10-4 tesla, which is about 3 orders of magnitude smaller than the general magnetic field intensity of the permanent magnet, so it has little influence on the original magnetic field of the permanent magnet. The influence of the magnetic field generated by the current on the original magnetic field is related to the measuring position, the shape of the magnet, the direction of the original magnetization and the direction of the current loading. In general, at a magnetic field intensity measurement point, if the annular magnetic field generated by the current is in the same magnetization direction as the original magnetic field, the magnetic field intensity increases after superposition, and the domain direction may change to increase the original magnetic field (when the permanent magnet is not completely magnetized). If the direction is not consistent, the magnetic field will weaken.
In addition, loading a current causes a rise in temperature, which may demagnetize the permanent magnet.
If an alternating current is added, an eddy current will occur in the permanent magnet due to the creation of an alternating magnetic field. For example, in the NdFeB permanent magnet synchronous motor, the eddy current loss of the permanent magnet synchronous rotor with a diameter of 100 mm can generally reach 10^(-2) ~ 10^(2) watts. Due to the high conductivity and high temperature coefficient of the neodymium magnet, it is easy to degrade the motor performance due to the temperature rise, and even have the risk of demagnetization.
In addition, there are electromagnetic damping, skin effect and other phenomena in some applications of load AC current.