Calculating Power Using 2 Phases Out of 3

[toasty55]

I have several heating elements that are wired using 2 legs out of 3 from a 480V 3 Phase Delta. For example looking at a particular heating element that is wired to phases A and B, with a voltage transducer wired in parallel, and a CT on Phase A. What would be the proper way to calculate power. Right now I am using the V * A * sqrt(3) but I am getting results of over 125% of my rated load (I am not including power factor since the load is purely resistive). Would the formula for a single phase system apply or would you use sqrt(2).

 

[david luchini]

I have several heating elements that are wired using 2 legs out of 3 from a 480V 3 Phase Delta. For example looking at a particular heating element that is wired to phases A and B, with a voltage transducer wired in parallel, and a CT on Phase A. What would be the proper way to calculate power. Right now I am using the V * A * sqrt(3) but I am getting results of over 125% of my rated load (I am not including power factor since the load is purely resistive). Would the formula for a single phase system apply or would you use sqrt(2).

Don't need the sqrt(3) part

 

[jaggedben]

... Would the formula for a single phase system apply or would you use sqrt(2).

Single phase would apply. That's all you're looking at in your example.

 

[toasty55]

Thanks for the clarification.