DC CIRCUIT PROTECTIVE GEAR Russian patent published in 2002 - IPC

FIELD: electrical engineering; contactless switchgear and protective gear for off-line equipment. SUBSTANCE: protective gear has final element, first current sensor, and amplifier; final element input functions as protective gear input and its output is connected to input of first current sensor; first and second amplifier inputs are connected to input and output of first current sensor, respectively; novelty is that protective gear is provided in addition with control unit, power amplifier, and threshold element, all of them organizing N-channel current limiter. In addition protective gear is equipped with second current sensor, current meter, and time meter; control unit input functions as control input of current limiter and output of first current sensor functions as its output; like-polarity inputs and outputs of N channels are connected in parallel; connection point of power inputs functions as protective gear input; control unit input of each of N channels is connected to amplifier output and to input of threshold element whose output is connected to first input of power amplifier; output of mentioned control unit is connected to second input of power amplifier whose output is connected to control input of final element; integrated outputs of N channels are connected to input of second current sensor; output of the latter functions as protective gear output and its metering output is connected to first input of current meter whose output is connected to input of time meter; output of the latter is connected to integrated control inputs of each of N channels. EFFECT: reduced loss during warm-up period. 2 cl, 3 dwg