A permanent magnet alone is merely a magnetic substance.

Strong magnetization applied by an appropriate method gives strong magnetism to this substance almost without changing its characteristics. Magnets are essential components for motors, sensors, communication, medicine, and control because of the characteristics that the N and S poles attract each other, poles of the same polarity repel each other, magnetic metals are attracted, and the angle of light reflection is changed.
　

A magnetizer power source is a device that magnetizes permanent magnets accurately and precisely to the number of poles and magnetization level necessary for meeting the diverse range of requirements in permanent magnet application fields. This device is a combination of a power source and a magnetizing jig.
　

Giving magnetism to a permanent magnet requires a very large energy. In general, a high voltage charged in a capacitor is applied to the jig at one time to apply a magnetic field to the jig and cause high magnetization. A magnetizer power source is selected by considering the material of the magnet, the number of necessary magnetic poles, and the magnet size.

Magnets are demagnetized for various purposes, one of which is recycling. In injection molding, a plastic magnet is used in a spool runner corresponding to the injection port for the mold. To recycle this magnet, the spool runner is crushed into small pieces. If the spool runner still has magnetism, the pieces may stick to each other or to the blade and so prevent the processing. Magnets are also demagnetized temporarily when securing them on a motor housing in the demagnetizing process. If the magnet still has magnetism, the assembling efficiency is reduced. Magnets requiring magnetization and demagnetization control are also demagnetized before remagnetization. In addition, defective magnets found by magnetization and demagnetization control are also demagnetized once before remagnetization.

Compared with general magnetic substances, a permanent magnet has a very great coercive force (HC) and cannot be demagnetized easily. To demagnetize such magnets, resonance attenuation demagnetization by a capacitor and a coil is used. Like a magnetizer power source, a high voltage charged in a capacitor is applied to the coil to generate a resonance magnetic field. Since the magnetic field attenuates while the N and S poles are reversed to each other, the magnet is demagnetized in the reversed magnetic field.

Note that SmCo and higher HC magnets are difficult to demagnetize completely to zero, and NdFeB magnets gain different initial magnetizing characteristics from the virgin materials when demagnetized.

When demagnetization is required, the jig should be selected according to individual conditions, such as the size and dimensions of the magnet as well as the number of poles.　The optimum demagnetizing device will be selected with information about the following items:

1. Magnet material (Manufacturer name for checking the magnetic characteristics

2. Magnet size and shape

3. Specification/No specification of magnetic waveform

4. Magnetization of a discrete or built-in magnet

5. Number of necessary magnetic poles

6. Full or partial magnetization

7. Magnetization output per hour