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. is related to the properties of thein which it magnetizes and then de-magnetizes. Theis generated by an. These are thewhich are produced in each area. This is calledB and its unit isdenoted 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.

Flux density that can be generated by the core. 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 thethat 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. between B and H is non-linear and both B and H are at zero point. If theincreases 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. always occur in transformers as thechanges its value and direction continuously and thein thewill cause losses because these changes direction continuously.



Rotating coils in DC Machines also occur hysteresis losses. inalso occur hysteresis losses.

Applications of Ferromagnetic Materials

Magnetic tapes, Hard disks and in Credit cards. In these applications, Hard magnets save data permanently and data cannot be erased easily from it. These materials are used in, Hand in. In these applications,save data permanently and data cannot be erased easily from it.

Soft magnets are used as cores which becomes electromagnets easily. are used as cores which becomeseasily.

















