Phase Power Calculation: Determining Total Power Input into System

[TurboST2]

Homework Statement

I need to calculate the power for phase A, B, and C so that I can determine the total power into the system.

I have measured the following data:
VA magnitude = 117.7 [v]
VA angle = 0°
IA magnitude = 7.5 [A]
IA angle = -25.5°
VB magnitude = 117.7 [v]
VB angle = -124.1°
IB magnitude = 7.7 [A]
IB angle = -145.7°
VC magnitude = 117.2 [v]
VC angle = 117.5°
IC magnitude = 7.3 [A]
IC angle = 94.8°

Homework Equations

P=IV

The Attempt at a Solution

Does this mean?:
Phase A power = 882.75 [w]
Phase B power = 906.29 [w]
Phase C power = 855.56 [w]

Total power into system = 2644.6 [w]

 

[NascentOxygen]

Hi TurboST2

So you didn't take phase angle into account? That means you've calculated volt-amps for each phase, not watts.

Does your textbook show a formula for AC power?

 

[TurboST2]

Thank you for the helpful reply. No I did not take the phase angle into account. I wasn't sure if this was necessary for calculating power in this way.

Taking the angle into account would I use this equation instead? P=VIcos(θv-θi) giving the following results:

Pa = 796.75 [w]
Pb = 842.64 [w]
Pc = 789.28 [w]

Ptotal = 2428.67 [w]

 

[NascentOxygen]

If you showed the data you used in arriving at those new numbers, it would be easy to judge whether you are on the right track.

What is the nature of your load here?