# Homework Help: Single phase transformer and net KVA output

1. Sep 23, 2014

### anand raj

1. The problem statement, all variables and given/known data
a 4 kva, 230/115 volt, 400 HZ, single phase transformer originally designed for use in air crafts, is available in a laboratory for obtaining 115 volt supply from standard 230 volt,50 HZ mains if overloading of the device is not permitted then net kva output is.........

2. Relevant equations

3. The attempt at a solution
here frequency is varying voltage remaining the same
kva being proportional to frequency
x = kva output for 50 HZ
4/x = 400/50
x = 0.5 kva
i dont know whether it is right or wrong, but the answer is this.

2. Sep 24, 2014

### Staff: Mentor

The wording of the question seems to imply (but stops short of stating unequivocally) that the transformer is to deliver 115V at 50Hz. I can't offer a technical opinion, but according to this reference http://www.edn.com/design/component...sformer-at-a-frequency-it-wasn-t-designed-for
Perhaps others can offer a critique of the suggested scheme.