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Apparatus for measuring electrical power

  • US 4,291,377 A
  • Filed: 11/02/1979
  • Issued: 09/22/1981
  • Est. Priority Date: 11/13/1978
  • Status: Expired due to Term
First Claim
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1. An apparatus for measuring power delivered at an alternating voltage by an alternating current to a loadcomprising in combination:

  • sampling means for periodically sampling the alternating voltage and the alternating current delivered to the load at selected sampling points,converter means, including impulse generator means, for converting the sampled points to first and second sequences of a plurality of pulses, the number of pulses in each sequence being substantially proportional to the instaneous values of the alternating voltage and of the alternating current, respectively,first counting means for counting the first sequence of pulses,second counting means for counting the second sequence of pulses,averaging means for determining the average value of said first and second sequence of pulses, respectively, over at least one period of the alternating current,subtractor measns for obtaining difference values between said average value, and said first and second sequences of pulses, respectively,multiplier means for multiplying said respective difference values, to obtain successive product values,integrating means for integrating said successive product values over said at least one period so as to measure the power delivered to said load, whereby any error in determining said average value is eliminated from the power measurement.

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