Remind me...current flow on single ended 3 phase loads

[hrc]

I am pretty sure we discussed this before....but I was trying to run thru my notes and did a search but didnt find what I was looking for.

Given a 208wye system, leg to leg connections to a load (single phase load). Each load draws 14A. So, if I have 3 loads, balanced across the legs (AB,AC,BC) each LEG will have a total current draw that is additive so 28A would be the draw on each leg. Correct?

 

[rcw retired EE]

Use kVA. 208 V x 14 A = 2912 VA per phase. x 3 phase = 8,736 VA.

8.74 kVA at 208 V: I = 8736/(208 x 1.732) = 24.24 A.

Remember youare adding currents vectorially.

 

[itsmoked]

rcwilson; nicely stated.

 

[hrc]

OK..that makes sense. I've done some measuring but at lower currents and the delta difference is harder to see there, but makes sense.

Thanks again guys, appreciate the help

 

[hrc]

Just thinking....what about unbalanced loads?

say 12A on one leg, 14A on another and 16 on the third?

A 208*12=2496
B 208*14=2912
C 208*16=3328

So AB = (2496/(208*1.732)) + (2912/(208.1.732)) = 15A

??