Field transients in magnetic systems

MAGNETIC CIRCUITS generally are composed of magnetically different materials which have different characteristics such as magnetization curves, electrical conductivities, and thermal properties. The most important distinction, however, lies in the use of laminated and solid iron parts, both of which show extreme behavior in the case of transient phenomena. When any change of the associated magnetic field takes place, eddy currents are produced in the iron, and these eddy currents produce a reacting magnetic field. This condition delays the rate of change of the resultant field. In the case of laminated iron parts, the very structure of the system limits the amount of eddy current to a negligible value. However, the delay of the growth of the magnetic field in solid iron parts is one of the most important factors in the operation of many types of electrical equipment.