I've already told you that is not correct. You only have 26.3 kva on one leg. Why do you keep putting the same incorrect
statements up. Did you not read my correction of your previous comment. The load is not 78.9 kva. Read the correction again
and see if you can understand why your information is wrong. Don't keep putting up incorrect information for others to read.
Perhaps you should re-read the OP. The question was
sizing of the transformer, NOT determining how much load was on the transformer.
Therefore, and using your numbers, exactly how do you buy a 3-ph transformer with one winding rated 26.3KVA and the other two rated 18KVA? (TTL 62.3KVA)
I did not state that the load was 78.9KVA, I said the non-std size transformer was 78.9KVA.
Further, using your number - would say that the transformer KVA needs to be 62.3KVA. Now, everyone knows that for a 3ph transformer the KVA is divided equally between phases; 62.3/3 = 20.8KVA.
So, exactly how are you supposed to feed 26.3KVA (your number) worth of load with a winding rated 20.8KVA? Even using a std 75KVA transformer your only going to get 25KVA per phase, meaning your still 1.3KVA short on one winding.
Perhaps you could enlighten us on transformer theory that would enable that to happen, of course assuming you are not adding fans (rather ludicrous for a 75KVA xfmr) or gaining KVA by buying one with a dual temp rating (again, odd for a small 75KVA unit)
)