Regulating transformer with magnetic shunt

A regulating power transformer having at least one primary winding and at least one secondary winding which are separated one from the other, and having at least one AC magnetic path through which an AC flux coupling said at least one primary winding to said at least one secondary winding can be established;

• and having at least one shunt member interposed between said primary and secondary windings, and placed between two portions of said AC magnetic path with an air gap at each end of said shunt member between the ends thereof and the respective contiguous portions of said AC magnetic path;
• at least one DC control winding arranged with said shunt member so as to pass through at least one window formed therein;
• the sum of the AC reluctance of the shunt member and the AC reluctances of the air gaps at the ends of said shunt member being less than the AC reluctance of that portion of the Ac magnetic path on which said at least one secondary winding is placed;
• so that, when there is zero current in said DC control winding, there is substantially zero coupling between said primary and secondary windings;
• the magnetic circuit for said at least one AC magnetic path having at least two core legs each having substantially uniform cross-section along its length;
• said magnetic shunt member having substantially uniform cross-section along its length except where said at least one window is formed, and further having a portion at each end of said shunt member extending past the respective air gap and over at least a portion of at least one side of the respective AC magnetic circuit flux path core leg;
• said AC magnetic path core legs and said at least one shunt member each being of laminated construction.