Magnetically controlled transformer apparatus for controlling power delivered to a load

摘要

A magnetically variable transformer having primary and secondary windings wound on a magnetic core wherein the transformer core with associated windings is placed in close proximity to an independently wound control coil. The control coil is positioned in one configuration on a focusing armature whose poles straddle the transformer core at positions on opposing sides. In a second configuration the transformer core is placed within the bore of the control coil and an optional focusing armature concentrates the magnetic field at the poles. Application of a control current forms poles at the control coil extremities and causes a change in permeability of the transformer core thereby altering the power output of the transformer inversely to the magnitude of the control current. The magnetically variable transformer controls a D.C. to A.C. inverter circuit which is useful in supplying power to a fluorescent lamp and other A.C. receptive loads. Additionally, a derived D.C. current from the output of the inverter circuit in series with resistive control elements modulates the level of the control current.