United States of America As Represented by the Secretary of the Air Force

National Technology & Engineering Solutions of Sandia, LLC

The University of New Mexico

Jane Lehr

James P O'Loughlin

Jason C Neely

Robert Kaplar

Jack David Flicker

Jacob Mueller

Diana L Loree

Gerald J Rohwein

Harold P Hjalmarson

Luciano Andres Garcia Rodriguez

Lee Gill

Gregory W Pickrell

Emily Ann Schrock

A disclosed switching apparatus, such as a circuit breaker, includes a transistor switch circuit connected between a power input terminal and a load terminal, and, connected to the power input terminal and bypassing the transistor switch circuit, a switchable bypass leg that is optically switched by a series-connected photoconductive semiconductor switch (PCSS). The transistor switch circuit includes at least one cascade of three or more series-connected transistors, and at least one resistor network configured to divide a voltage from a voltage source across a cascade of series-connected transistors. Operating the switch apparatus includes detecting whether a sensed electric current is in a fault condition, opening the transistor switch circuit upon detecting a fault condition, and then closing the PCSS so that the electric current is diverted onto a switchable bypass path. The opening of the transistor switch circuit comprises turning OFF a normally-ON transistor switch circuit.

Optically switched circuit breaker with cascaded transistor topology

A slotted coaxial shield for high voltage cylindrical air core transformers is described that controls the electric field stress while permitting the rapid extraction of electric energy stored in the shield to improve the output efficiency.

Air core transformer with coaxial grading shield

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Placitas, NM, United States of America

Jane Lehr