New developments in current-transformer design

VERY noteworthy progress has been made in recent years in the design of current transformers for medium and high voltages. Previously most current transformers were designed and built according to the same general practices as a small power transformer, and its size, weight, and general appearance was that of a conventional transformer. The latest current transformers, described below, scarcely resemble their prede-cessors — their weight, size, etc., are but a small fraction of the older designs. A comparison of the principal data of two current transformers — one designed in 1929 and the other of recent development — may be of interest (table I).