METHOD OF AND DEVICE FOR OVERLOAD PROTECTION OF RAILWAY CONTACT SYSTEM Russian patent published in 1994 - IPC

FIELD: electrified transport; overload protection of contact system and other networks. SUBSTANCE: temperature of conductor is measured and converted into first electric signal proportional to value given in description of invention. Second electric signal proportional to time interval from moment of beginning of overload is formed and compared with first signal. If second signal exceeds first one, signal to switch off panel is generated. Device has temperature sensor, threshold element, pulse counter, NOT gate, time delay element and first output member. Novelty is introduction of first and second summers, squarer, voltage-to-frequency converter, flip-flop, first output member position repeater, four control factor units, reference voltage source and second output member. Provision is made for indication of beginning of overload and inhibition of reclosing when conductors are still hot. Values of constants B and C are given in description of invention. EFFECT: enhanced overload protection of systems. 3 cl, 1 dwg