(Winne)
"If you look at this from the other side: consider a 120/208V wye system, and place a single phase 16 ohm resistive load between phase A and phase B. 13 amps will flow through this resistive load, and 2704W will be delivered to the load. But for 13A to flow through the load, 13A has to flow through both phase A and phase B. This means that 1560VA is being supplied by each phase. If 3120VA is being supplied, but only 2704W delivered to the load, then there has to be a power factor somewhere "
(Bob)
I do not know where you get the 1560 VA or the 3120 VA. None of the values in the problem when properly used can produce this figure.
Power = I²xR = 13²x 16 = 2704 watts.
Power = V x I = 208 x 13 = 2704 watts.
Where did you get these numbers?
(Winnie)
The phase A wye connected transformer coil is delivering 120V phase to neutral. 120V * 13A = 1560 VA. Same for phase B.
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Guys... stop thinking of a single phase load as being connected across two phases. It is not so. It is connected across two voltage sources in series. The current flow is supplied by both sources equally.
Winnie... in this discussion the face that both phase a and phase b is delevering 120 volts phase to neutral is not important as the load is not connected to the neutral.
Think of this from the perspective of DC for a second. Two 12 volt car batteries connected in series so that positive pole is connected to negative pole to give us 24 volts... both batteries supply the full current.
Ohhh... I love these threads...
