What is the hysteresis property of ferromagnetic materials?
When the current in the coil is reduced to zero, that is, the magnetic field strength H=0, the magnetic flux density (B1) retained in the iron core is called remanence. At this point the core is magnetized. If the remanence of the core is to be eliminated, the direction of the current in the coil can be changed, i.e., reverse magnetization is required to change the direction of the magnetic field intensity H. The H value of remanence disappears, called coercive force.
As you can see from the diagram, when the H has been reduced to zero, the magnetic flux density B of the core has not returned to zero. The magnetic induction intensity lags behind the variation of magnetic field, called hysteresis of magnetic substance.The curve depicted in the figure is called a hysteresis loop. The magnetic hysteresis loops of magnetic materials are different.
When the iron core coil making core by alternating current, alternating magnetization. The relation between the magnetic flux density B and the magnetic field intensity H is changed when the current changes at one time.
Hysteresis is an irreversible change in magnetic induction or magnetization that varies with magnetic field strength in ferromagnetic or ferrimagnetic material.
