ELECTRONIC WATT-HOUR METER

摘要

An electronic watt-hour meter having a function of cutting off a load when detecting a consumed power limit and requiring no special current sensing means because the consumed power limit is detected with the electric energy. Uneven power distribution that the maximum consumed power at the end of the distribution line is less than the others due to the lower supply voltage at the end is prevented. Power/frequency converting means (22) multiplies the voltage signal by the current signal and outputs power pulses proportional to the electric energy. A limit power judging section (30) counts the power pulses for a predetermined time and outputs a load cutoff signal if the count exceeds a predetermined load cutoff value. A warning output level of a warning value smaller than the load cutoff value is set, thereby issuing a warning before the load is cut off.