New applications of non-linear circuits to relay and control problems

Abstract

The fundamental relations between voltage and current for an iron core reactor are reviewed. The theory of the performance of such reactors in series and parallel resonance circuits may be qualitatively obtained by graphical means. For reactors which have nearly linear properties the graphical method is capable of yielding quantitatively accurate results. A fundamental analogy exists for the properties of series and parallel resonance circuits employing the same inductance and capacitance elements. It is shown that; (a) for the series circuit the current is functionally related to the voltage in the same manner as, for the parallel circuit, the voltage is related to the current, if (b) for the inductance element the current is functionally related to the voltage in the same manner as, for the capacitance element, the voltage is related to the current. It is stated that in the series or parallel circuit, means are available for causing the current, as the dependent quantity, to vary as a function of voltage, as the independent quantity, or vice versa. Because of this generalization, the series circuit which is sensitive to voltage changes can also be caused to function as a constant-voltage source, insensitive to current changes. Similarly the parallel circuit, which is sensitive to current changes, can be used as a constant-current source, independent of voltage changes. The voltage sensitivity of the series circuit and the current sensitivity of the parallel circuit are applied to the problem of voltage and current relays.