3Ph Power Calc on a Load Panel

Discussion in 'General Electronics Chat' started by Management, Nov 9, 2012.

  1. Management

    Thread Starter Active Member

    Sep 18, 2007
    If I have a 3-phase delta connection load panel, how do I determine the aggregated power of that panel if I know the load currents on each phase? Do I just sum them up?

    Voltage across each phase is 208V but let's assume it is Vab, Vbc, & Vac.

    If it was a balanced load and the current was then I think the apparent power would be equal to sqrt(3) * Vrms * Irms. Is that correct?

    If there are single phase loads on this 3 phase load panel then one should try to distribute the load as equally as possible but it won't be perfect. What would the equation for the total apparent load would be for the panel?

    I have the Irms (real) per phase and Vrms (real) per phase for each load and since I have the power factor I can determine my apparent power per phase by dividing (correct?)

    Do I just sum up the apparent power for each phase? :confused: Or do I sum them up and divide by sqrt(3)?
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    add them up, and if it's balanced, you'll note the sqrt3 relationship.
  3. Management

    Thread Starter Active Member

    Sep 18, 2007
    Ok so I have everything else correct and only divide by sqrt(3) if the system is balance, i.e. sum them up if separate loads on each phase?

    Why is that?

    Thanks for replying.
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    Power W= V x I x 1.732 for a balanced system

    for non balanced W = V x I per phase then add the W's all together