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Homework Help: Instantaneous power calculation between equal time increments.

  1. Jan 14, 2014 #1
    1. The problem statement, all variables and given/known data

    If given cumulative (Adding up every increment to the next) KWh values at an interval of 5 mins each. is it possible to determine instantaneous power from it?

    2. Relevant equations
    P(t) = VI cos(ωt) cos(ωt −θ )

    3. The attempt at a solution

    Well, because the question is more about stating a method than actually calculating something. I have thought about it. I think the instantaneous power should just be the difference of Power at time1 and Power at time 2, in this case. Now, of course, if i actually had a circuit, i could go around doing analysis and coming up with Voltage in terms of time and Current in terms of time. That way i can easily come up with a function of instantaneous power with a variable of time in it.
    But what this stats is more like, if you are given a value of power for every 5 minutes then what the instantaneous power should be using only the data given? I can't think of much except for taking the value of power at time 2 and subtracting it from value of power at time 1. And that should give me the power that was recorded between those 2 instances.
  2. jcsd
  3. Jan 14, 2014 #2


    User Avatar
    Science Advisor

    No, it is not possible to find an instantaneous power. The best you can do is the average over 5 minutes because that is all the information you have.
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