# 3 phase power systems

Discussion in 'General Electronics Chat' started by coley01, Jun 30, 2010.

1. ### coley01 Thread Starter New Member

Jun 30, 2010
1
0
I am trying to calculate the power consumption for a 3 phase motor. The load is varying so I am taking the current readings on each of the 3 phases every second. I know the voltage and power factors. I originally thought I would just calculate Pi=I*V*PF*3600 to get Wh for each phase and then just add the three phases and then add all the Pi's for a day to know the power consumption for one day. Then I was looking at 3 phase calculations and it said you have to multiply by the square root of 3. Is this correct? Would I have to multiply Pi by the square root of 3 and then do the summation.

2. ### Dx3 Member

Jun 19, 2010
87
7
A quick search for "3 phase power formula" got me, "real power = radical 3 EI cos theta"

3. ### GetDeviceInfo Senior Member

Jun 7, 2009
1,571
230
Power consumption is volts x amps x sqrt2. Power output is reduced by the power factor.

I mean sqrt 3.

Last edited: Jun 30, 2010