CURRENT RELAY

electrical engineering; electronic relays. SUBSTANCE: current relay has series-connected intervening current transformer; first and second AND gates whose inputs are connected to HIGH and LOW outputs of threshold unit, respectively; reversing counter whose adding and subtracting inputs are connected to respective outputs of first and second AND gates; second and third threshold units whose outputs are connected to inverting inputs of first and second AND gates, respectively; final element whose input is connected to output of reversing counter; series-connected clock generator whose output is connected to second input of first AND gate; pulse frequency divider whose output is connected to second input of second AND gate; and also one-shot multivibrator whose output is connected to resetting input of reversing counter and to trigger input of clock generator; final element may be made in the form of threshold unit with relay incorporating make contact connected to its output either directly or through amplifier. EFFECT: enhanced noise immunity. 2 cl, 2 dwg