TRACTION DC DRIVE Russian patent published in 2013 - IPC B60L7/12 

FIELD: transport.

SUBSTANCE: invention relates to railway transport and may be used at vehicles with dc traction motors. Proposed traction drive comprises power supply, first contactor, armature and excitation windings of first and second dc traction motors, all being connected in series, as well as armature and excitation windings of third and fourth dc traction motors, and two diodes. First diode is connected via common terminal of first contactor and first traction dc motor armature winding. Traction drive comprises also third contactor, storage battery, fourth, fifth, sixth, seventh and eighth contactors. Free terminal of fourth traction dc motor excitation winding is connected to common terminal of first and second contactor. Cathode of second diode and first terminal of fourth contactor with its second terminal connected with free terminal of second traction dc motor excitation winding, first diode anode and first terminal of fifth contactor. First terminal of sixth contactor is connected with second diode anode and storage battery cathode. Note here that second diode anode is connected via seventh contactor with common terminal of second traction dc motor armature winding and first traction dc motor excitation winding.

EFFECT: smooth adjustment in traction and electric braking modes.