 This is going to be a walkthrough of how to deal with ratings on a multi winding transformer Let's get started here. The first thing we have to do to do is to determine Which is our high side and which is our low side? Well, if you notice here, we've got these leads H1 H2 H3 H4 Those H leads stand for high voltage. So that's my high side down here X1 X2 X3 X4 Those are my lower voltage windings Now what do I mean by that? Now let's take a look over on this guy right here I have the transform that is rated 10 kva 600 volts 300 volts to 1 22 40 volts Now looking I've got 600 300. That's a higher voltage than say 120 240. Makes sense Now what we're going to do is we're going to determine each winding rating and the way we do that is and let's talk just about the high side first We look at the lower voltage 300 volts with these two voltages 600 and 300 We're going to take the 300 volts and that is our winding rating. So let's get that written in there So that is a voltage rating of each winding So when they built this the insulation and the winding can handle 300 volts of pressure on that winding and this one You can handle 300 volts of pressure now. What's this 600 volt for you ask? We'll talk about that in a later video Let's look at the X side or the low side. We have the same situation. We have a hundred and twenty two hundred and forty volts We're going to take the lower of the two voltages one hundred and twenty volts and we're going to apply that to each winding So now we've determined what each winding is rated to handle our next step in this is we notice that we have a 10 kva rating here Now what we're going to do is we have to split that kva in half And that is what each winding can handle as far as kva output or input is concerned Therefore 10 kva cut in half you do the math in your head. That's five kva each winding Now remember va n equals va out so that va Five kva per winding I've got five kva there five kva there five kva there and five kva there So I have 10 kva on my top side and 10 kva on my bottom side. Let's get that written in Now what that kva allows us to do is to determine the current through each winding so we know that this guy can put out Five kva. We know that it's voltage rating is 300 volts So if we take five thousand divided by three hundred It means that this winding here can handle sixteen point seven amps and this one here can handle sixteen point seven amps Now let's talk about the secondary Again, we are going to take the kva the five kva and we're going to divide that by a hundred and twenty volts And we're going to get our current Which works out to be forty one point seven amps So there we go. We've now figured out what our Kva rating is our voltage rating and our current rating on our primary our kva rating our voltage rating and our Current rating on our secondary the only thing left to figure out when we're talking about our ratings are It's not our is the turns ratio and the way we're going to get that is we're going to take the lower voltage and The high side and the lower voltage of the secondary side And we're going to divide them to get our turns ratio because remember turns ratio is always based off of winding to winding So three hundred divided by one hundred and twenty Gives us a turns ratio of two point five to one now remember whenever I do these ratings It is irregardless of how it's connected. I just deal with the ratings over here and work out everything I don't care if we got like this guy being parallel connected or this guy being series connected Do not even look at the connections yet Just get your ratings in there and in the next video. We'll start connecting and taking a look at what happens