using ferroresonant transformers as final control devices

Full Title

Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems > Regulating voltage or current (G05F1/02 takes precedence) > wherein the variable actually regulated by the final control device is AC (G05F1/625 takes precedence) > using ferroresonant transformers as final control devices