FIELD: railway transport; automatic control of traction motors with protection of control power circuits. SUBSTANCE: device has current limiting resistor and relay element with break outlet contact. Novelty is use of relay element with thermal relay whose heating element is connected to first stage field weakening resistor and contact is installed for mechanical locking in switched off position. Device uses series connection of thermal relay contacts which control traction motors field weakening resistors of parallel circuits. EFFECT: improved reliability of protection. 1 dwg
