Magnetic Hysteresis - Magnetic Hysteresis Loop - B-H Curve - Magnetic Hysteresis Loops for Soft and Hard Materials - Applications of Ferromagnetic Materials
Magnetic Hysteresis
Magnetic hysteresis is related to the properties of
the ferromagnetic material in which it magnetizes and then de-magnetizes. The
magnetic flux is generated by an electromagnetic. These are the Lines of force
which are produced in each area. This is called Flux density B and its unit is Tesla denoted by T.
B-H Curve
For ferromagnetic materials, the ratio between the
flux density (B) to its field strength is not constant and it varies with flux
density. If we draw the curves according to the values of flux density against
field strength. We can produce a set of curves called B-H Curve and it is also
called Magnetic Hysteresis Curves.
As shown in the above figure, you notice that every type of core
material have its own set of magnetic hysteresis curves. As you observe
that the flux density of various materials increases in proportion to the field
strength. The reason is that there is a specific amount
to limit the Flux density that can be generated by the core.
Magnetic Hysteresis Loop
The Magnetic Hysteresis Loop between B and H is non-linear
and both B and H are at zero point. If the magnetization current increases in a
positive value. The field strength increases linearly and the flux density B also increase as shown by the curve.
Magnetic Hysteresis Loops for Soft and Hard Materials
Hysteresis losses always occur in transformers
as the electric current changes its value and direction continuously and the magnetic
poles in the core will cause losses because these changes direction
continuously.
Rotating coils in DC Machines also occur hysteresis losses.
Applications of Ferromagnetic Materials
These materials are used in Magnetic tapes, Hard
disks and in Credit cards. In these applications, Hard magnets save data permanently
and data cannot be erased easily from it.
Soft magnets are used as cores which becomes
electromagnets easily.
