ELECTRIC METER WITH PROTECTIVE CUTOUT Russian patent published in 2013 - IPC G01R11/00 

FIELD: electricity.

SUBSTANCE: electric meter with protective cutout containing current sensor which outputs are connected to current-by-voltage multiplier which in its turn is connected to current-to-pulse frequency converter, current transformer with two primary windings and one secondary winding at which the signal is proportional to current difference of primary windings and rectifier; at that outputs of the transformer through rectifier converting alternating-current signal into a direct-current signal are connected to current-to-pulse frequency converter; at that when a signal at the rectifier output exceeds a signal from current-by-voltage multiplier and it is fed to current-to-pulse frequency converter then this current-to-pulse frequency converter will ensure maximum frequency of pulses; it includes an auxiliary voltage peak protective relay which outputs are connected to phase and neutral conductor of the measuring circuit, primary windings of the transformer are connected to phase and neutral conductor of the measuring circuit through a normally closed contacts of the voltage peak protective relay.

EFFECT: ensuring protection of electric meter from voltage surges or low voltage in the mains.

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