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Power consumption detecting circuit for loads in AC network - uses point-on-wave timing to confine current detection to region near peak of AC voltage wave and exclude reactive components
Power consumption detecting circuit for loads in AC network - uses point-on-wave timing to confine current detection to region near peak of AC voltage wave and exclude reactive components
A circuit for establishing the presence of an energy consuming load in an AC network (30,31,39), by means of selectively timed current measurements, employs a resistor or current transformer as an initial monitor stage (33). A point-on-wave selector (34) confines current monitoring to a short predetermined time interval in the region of peak network volts via the electronic switch (35). During this period only any current signals (38) from the monitor (33) are assessed by the max. voltage detector (36) and above a preset threshold result in a detection signal (37). At all other points on the voltage wave current signals (38) are disconnected via the switch (35) so that wattless, i.e. capacitive/inductive loads are excluded. USE/ADVANTAGE - Simple and economic means of detecting power consuming loads not affected by presence of reactive loads. Obviates need for relatively expensive wattmeter alternatives in, e.g. sequential switching of multiple loads.
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