Improvements in apparatus for the transformation of electric alternate currents into direct currents and vice versa

摘要

292,617. Urbinati, M. June 23, 1927. [Convention date]. Commutator switching-arrangements; polyphase transformers.- In conversion apparatus of the type in which a polyphase transformer is adapted to provide current of a large number of phases associated with stationary segments of a commutator cooperating with synchronously rotating brushes, difficulty arises in obtaining from, for example, a three phase primary, the requisite large number of secondary phases by phase combination due to the value of volts per turn being higher than the amount to be added or subtracted to produce the necessary small phase displacement. This difficulty is overcome by providing in addition to turns on the secondary side embracing the whole of the iron cross-section, turns embracing various fractions of the iron cross-section as shown, so that fractional values of the volts per turn are available for adding or subtracting in combining phases.