Voltage regulating transformer

Claim 1

A ferro-resonant voltage regulating transformer, comprising: A. first and second permeable magnetic cores, said cores spaced by an air gap and said first core comprising a closed magnetic circuit, said second core having an air gap, B. a primary winding for connection to a source of alternating current of fluctuating voltage, said primary winding arranged around a portion of both said cores for inducing a magnetic flux therein, C. a resonant secondary winding having first and second terminals, said resonant secondary winding being arranged around a portion of said first core, so that a voltage is induced in said resonant winding in response to the magnetic flux in said first core, D. a capacitor in parallel with said resonant winding, said resonant winding and said capacitor forming a resonant circuit which resists voltage increases across said resonant winding beyond a preselected level and thereby substantially limits the maximum instantaneous magnetic flux in said first core over a range of primary voltage variations to regulate the voltage across the resonant circuit, whereby a substantial flux flows in said second core when the flux in said first core increases beyond the preselected level. E. a direct transfer winding arranged around said primary winding, said primary winding inducing a voltage in said direct transfer winding proportional to the primary voltage, F. a secondary correction winding around a portion of said second core, said correction winding being connected in series with said resonant winding and said direct transfer secondary winding so that the regulated output voltage is the sum of the voltages across said resonant winding, said direct transfer secondary winding and the correction winding, and whereby the flux in said second core induces a voltage in said correction winding to compensate for fluctuations in the voltage across said direct transfer winding.