I have a transformer with three input terminals and three output terminals. I tested my transformer using two of the phases as input, I got the output around 14 volts,
And then next I supplied it with single phase of 230 volts, it gave the output around 7 volts, i.e. exactly half the value which I had got using two phases as input.
I am not able to judge what type of transformer is it?
Actually I want to design a circuit in which I need to check the presence of all the three phases?
Re: transformer basics
What are the terminals labelled? Photo (with the markings readable)? Is the transformer an open-frame type or is it enclosed? Another photo? What voltage was the "two phases"? What country are you in? There's not enough information there for me to help you.
What do you mean by "check the presence of all the three phases?" Do you mean exactly that - a phase failure detector - or do you want more detailed information about the quality of the supply, rather than just the presence or absence of part of it?