DIRECT-CURRENT MACHINE Russian patent published in 1997 - IPC

FIELD: variable-speed electric drives or variable-speed generators with constant output characteristics of generated electrically for general- or special-purpose applications. SUBSTANCE: electrical machine is physically built up of three functionally coupled AC machines. First (input) machine has rotor carrying additional magnetic core 5 with inductor winding 6 of second AC machine made in the form of hollow barrel with copper and ferromagnetic segments alternating over circumference. Copper segments are shorted out on one end to form single-turn coils and on other end they are connected to two end rings 22 and 23 of two polarities. Inductor winding 6 of second machine is closed through winding of unipolar exciter armature 7; unipolar exciter has toroidal field winding 16 combined with magnetic circuit of unlike-polarity magnetic system 17 carrying winding 18. Second-machine armature winding 8 is wound on inner cylindrical surface of additional magnetic core 5 of stator. Third-machine armature winding 10 is wound on its outer surface. Both windings 8 and 10 are shorted out through each other. Third-machine rotor magnetic core 11 is mounted on separate shaft 12 and has its own bearing supports 13; it is, essentially, hollow barrel physically embracing at end frame 2 of two first combined AC machines. Speed of third-machine output shaft 12 is steplessly controlled by field winding of unipolar exciter at constant speed of first input machine. The latter is started at no load and does not require any significant starting-to-running torque ratio. EFFECT: improved power factor of input circuit, provision for starting-to-running torque ratio maintained at its maximum level. 2 cl, 3 dwg