Analysis of instability and response of reactors with rectangular hysteresis loop core material in series with capacitors

An exact analysis is given for a reactor having an idealized magnetization characteristic consisting of two linear regions of zero inductance, interrupted by a linear region of infinite inductance, when connected in series with a load comprising of capacitance and resistance under the action of a sinusoidal applied voltage. The recent developments in core materials have introduced magnetic materials such as Deltamax* and Orthonol† which have magnetization characteristic, at high values of saturation, approximating the ideal case. Thus the results obtained on the basis of an idealized analysis show good correlation with practical results obtained by experimenting on Deltamax cores. The circuit analyzed is the simplest circuit exhibiting an unstable and multivalued behavior attributed by several authors to a nonlinear resonance, sometimes referred to as ferro-resonance phenomenon. Since the ideal magnetization characteristic assumed, consisting of regions of zero and infinite inductance, could not resonate with the finite load capacitance, the behavior of the circuit is explained by a different approach.