Thanks Gold digger,
Ok let me ask this way as this thread see a to only adding to my confusion.
Just an answer:
Solve for x
A 50 kva transformer per phase supplies how many amps???
1 phase delta x = ?
3 phase delta x = ?
1 phase wye x = ?
3 phase wye x = ?
I think what your missing is that the KVA is the power your assigning to amps, to get power you multiply amps times volts which is the VA in KVA and without getting into power factor, this also can be called watts (if we ignore power factor) which is what we pay for at the electric meter, so in a three phase circuit this wattage is divided between 3 conductors, this is why we use the square root of three (1.732) to calculate how many amps a given watts into a transformer will produce on each phase of the transformer, we use the term KVA versus watts to define the difference between real power and apparent power this is also called the power factor.
so when we calculate power as voltage times amps we are figuring real power, if we have a motor that can be wired to run on 120 volts or 240 volts, and lets say this motor uses 1,000 va, we will see it draws 8.34 amps on 120 volts and 4.16 amps on 240 volts, the the power it is using is still the same 1,000 va or 1kva, the same motor on three phase will use 2.40 amps @240 volts but we still are using 1kva of power so the cost of running that motor is still the same, the benefit is we now have less amps and our wire sizes can be smaller as well as the motor will operate more efficiently on 3-phase, but thats another chapter.
so we are not changing the amount of power consumed, we are just changing the perimeters of how we are using that amount of power by using 240 volts we have cut the current in half so we can use smaller conductors, but the amount of power is the same and using three phase over single we have cut the current farther by dividing the single phase current with the square root of three (1.732).
so when we look at a singe phase transformer versus a three phase transformer, both 50kva transformers will supply the same amount of power, but the current is going to be less on the three phase transformer because we have divided that power across three conductors instead of 2, this is what the square root of three does in the equation.
Remember we don't pay the utility by how many amps we use, we pay them the amount of volts times amps or watts we use, this is called power.