FREQUENCY RELAY Russian patent published in 2004 - IPC

FIELD: electrical engineering.

SUBSTANCE: given frequency relay has isolation transformer, frequency filter, two pulse formers, two formers of short pulses by change of input voltage, two AND gates, frequency-dependent element, NOT gate, actuating element, pulse stretcher, subtracter, comparator. Frequency-dependent element is intended to form signal, which amplitude decreases proportionally to value of modulus of deviation of frequency of input voltage from rated value and phase alters proportionally to value and sign of deviation of frequency of input voltage from rated value.

EFFECT: increased accuracy of frequency relay.

2 dwg