Magnetization, Cycle of.
A cycle of positive or of positive and negative magnetization represents
the application of a magnetizing force beginning at a fixed value,
generally zero, rising to a maximum, or to a value of maximum distance
from the initial and then returning to the original basis. It is
virtually a full wave of magnetization and may extend on both sides of a
zero line giving positive and negative values.
Cycles of magnetization apply especially to transformers and other
apparatus of that character used with the alternating current system.
Magnetization, Hoffer's Method.
For horseshoe bars an armature is placed against the poles of the magnet
bar to be treated. The poles of a strong horseshoe magnet are stroked
over it from poles to bend and returned through the air, or vice versa.
In the first case the poles will be the same as those of the inducing
magnet; in the second case they will be opposite. A maximum effect is
produced in ten strokes. The stroking should be applied to both sides.
An electro-magnet may be used as inducer as shown, but an armature
should be used; in the cut it is omitted.
Fig. 229. MAGNETIZING A HORSESHOE MAGNET.
Magnetization, Intensity of.
The amount of magnetism induced in or present in a body. It is expressed
in Magnetic Lines of Force, q. v., per cross-sectional area.
Magnetization, Isthmus Method of.
A method used by Ewing in a research on the magnetization of iron in
very strong fields. He used samples of iron turned down in the centre to
a narrow neck, and thus concentrated the lines of force greatly.
Magnetization, Elias' Method.
The bar to be magnetized is surrounded by a magnetizing coil, q. v. A
strong current is passed through it, and the coil is moved back and
forth a few times.
Magnetization, Jacobi's Method.
For horseshoe bars. The bar is placed with its poles against those of a
horseshoe magnet. A bar of soft iron, long enough to reach from outside
to outside of the legs, is laid across near the junction and is drawn
along towards the bend of the new bar and away from it. This is repeated
a few times on both sides.