Electricity metering equipment

Claim 1

An electricity metering equipment, comprising: (A) electricity metering means for measuring an amount of electricity consumed in a load connected to an electricity supply via said metering means, said metering means producing impulses each of which represents consumption of a given amount of electricity; (B) means independent of said metering means for producing a first signal representative of a current supplied to said load; (C) means for deriving from said metering means per se a second signal representative of a rate of consumption of electricity in said load as measured by said metering means per se; and (D) comparison means, responsive to said first and second signals to produce an output signal in response to a predetermined discrepancy between said first and second signals, said comparison means including means for producing an output signal when the rate of consumption of electricity as represented by said second signal is below a rate corresponding to a predetermined value of the current supplied to the load as represented by said first signal, and the value of the current supplied to the load as represented by said first signal is not less than said predetermined value, said means for producing an output signal including (i) a counter means for providing a count of impulses produced by said metering means in a predetermined period, (ii) a comparator for comparing the count of the counter means for each said predetermined period with a predetermined count corresponding to said predetermined value of the current supplied to the load, and (iii) means for inhibiting the comparator when the value of the current supplied to the load is less than said predetermined value.