Magnetization / Demagnetization

  What’s on earth magnetizing power supply ?

 
Once strong magnetism is given to it with an appropriate means, then it becomes to wear strong magnetism
or the first time and that character is almost kept stay.
Making use of the character like unlike poles attracts and like poles repel, ferro magnetic materials are
attracted and angle of reflected light is changed, now magnets are placed as indispensablitem used for
motors, sensors, communication, medical appliances and controlmanagement.
Magnetizing power supply is the equipment which puts magnetizm onto permanent magnets precisely according
to the verious requirements from the market such as how many poles and how strong it should be and
it is used with special fixtures to magnetize.
As quite strong magnetic forth is necessary to magnetize permanent magnets, generally discharging
high voltage electricity charged in the capacity to the fixture at once, quite strong magnetism generated
by the fixture is given to magnets. To select appropriate magnetizing power supply quality of magnet,
the number of poles magnetized and the dimensions of magnet is taken into consideration.

  What’s on earth demagnetizing power supply ?

There are many ways to demagnetize magnets. One of them
is for recycling. Bonded magnets are always injection molded with sprues as excess materials which are
from sprue runner. When you try to crush them into pieces for recycling they must be demagnetized first
because they will be bunching up together or attach the blade during crush process by residuel magnetism
from them so that operation itsself can not be done.
And some motors are pre-magnetized to fix magnets on stator. If residual magnetism remains on magnets
in assemblying process, effecency of process will be fallen down so that demagnetization is necessary.
As for magnets need to be controlled magnetic flux coming out of magnets, those which are NG are
demagnetized before magnetizing them again.
Coercive forth(HC) of permanent magnets are compareing with general farro magnetic materials quite high
so that it is rather difficult to demagnetize. To demagnetize them attenuating demagneetization by
capacitor and solenoid coil is taken. Like magnetizing power source, applying high electrical charge stored in capacity
to solenoid coil, generate attenuating magnetism. N and S is alternating with attenuation in solenoid coil
and magemts are demagnetized in this akternating magnetism.
It is quite difficult to demagnetize magnets with high ceorcive forth such as to zero level of residual
magnetism with high ceorcive forth higher than samarium cobalt magnets.
Besides once neodymium magnets are demagnetized, as initial magnetizing characteritics is changed
it must be treated carefully.