Power calulation of 3-phase model

Hi folks,

i am new at the forum and one really important question i never found here - reason is that we have an equipment of about 40KW installed and about 100.000KWh power consumption per year and i would like to check out our Limits that the environment is able to deliver with given fuses of 3x80A. Ok, it's the other way to use a flukso, but it is a new point of view maybe.

What is the fundamental mode to calculate power consumption of 3-phase model flukso's?

a) Phase by Phase which means:
Displ.power=current1(A)x230V + current2(A)x230V + current3(A)x230V

b) MeanValue (Average) 3-phase calculation:
Displ.power= AVERAGE(current[1-3](A) x 1,73 x 400V

c) Real 3-phase calculation:
Displ.power=SUM(current[1-3](A) x 1,73 x 400V

Thank you and regards


PS. I also would like to introduce myself here to this fantastic project forum. I am *nix Admin and Storage/Broadcast-Equipment expert at AVID in Germany. I ordered two Flukso units to check out power consumption (and reduction) at my brothers bakery and one Flukso for my home too. I'm very curious about to get these little boxes running... :-)

icarus75's picture

Hello cackermann,

Welcome to the forum! The easiest way to approach a three-phase supply is to take the sum of the three individual phases. For a system having 400V between each of the three phases L1, L2 and L3 and thus 230V between Li and N (i=1..3) we get:

P = I1rms*V1rms + I2rms*V2rms + I3rms*V3rms (your equation a)

Assuming Virms = 230V for each phase:

P = (I1rms + I2rms + I3rms) * 230V


P = Iavg,rms * 3 * 230V

P = Iavg,rms * 1.73 * 400V (your equation b)

So for a three-phase supply with each each Li-N phase having a Virms of 230V, equations (a) and (b) are equivalent. Your equation c seems incorrect to me as it will result in a power calculation which is a factor 3 too high.


cackermann's picture

Thanks Bart

you're right with your explanation of calculating power consumption. Indeed formular #3 is a crap; maybe t'was a litte bit too late... ;-)