Abstract: An auxiliary winding is provided on a ferroresonant voltage regulating transformer. The transformer is controlled in such a manner that, during start-up of a load connected to the transformer, the auxiliary winding provides all the current for the load, and after the initial start-up period of the load, the auxiliary winding is disconnected from the load and the normal secondary winding of the ferroresonant transformer supplies all the current to the load. It should be noted that the auxiliary winding is constructed so that (in theory) all the flux from the auxiliary winding is linked with the primary winding, and all the flux from the primary winding is linked with the auxiliary winding.

Abstract: In a push-pull inverter (including a transformer) for changing direct current into alternating current, a circuit is disclosed for starting the inverter in which the first pulse of a rectangular pulse train applied to the transformer has a duration of one half that of the subsequent pulses. This aids in reducing the initial magnitude of the flux excursion in the transformer core.