 In the last video, we talked about getting your ratings in the windings of a multi-winding transformer. This video is going to be about how we connect and talk about the voltages and the currents as these windings are connected. Now let's just talk about the ratings quickly first. Again, we take the lower voltage of each one. So we have a 600 and 300 volt transformer to a 120 to 240 volt. We take the lower of the voltages for the high side. That's the 300 volts there. Take the lower voltage of the other side, the low side, 120 volts there. Again, just as always, we split the KVA up on a multi-winding. So we end up with 10 KVA per winding and then we get our current from that KVA rating. So 10,000 divided by 300 gets me 33.3 amps per on the high side and 10,000 divided by 120 gets me 83.3 amps per on the secondary side. Now you'll notice on the primary, I've got a bus and my bus is 600 volts. What we do here is this is a supply voltage coming in and we take a look at our windings. We see that each winding is rated at 300 volts. The only possible way that we can safely connect this is in series because voltages when they're in series add. So this one was rated for 300 volts. This one was rated for 300 volts. In order to safely put 600 volts across it, we'll put this in series. So connecting h2 to h3 and that way we end up splitting the voltage 300 plus 300 and we can safely put that 600 or that 600 gets cut in half, 300 volts gets impressed across that guy, 300 volts gets impressed across that guy. Now we also need to discuss and I forgot, we'll just quickly talk about the turns ratio. So we have 300 volts and 120 volts. Our turns ratio is 2.5 to 1. Therefore we take 300 divided by 2.5 and that's where we get the 120 from, which is our rated as well. So we have 120, 120 on that side there. So we've talked about the voltage on top. Let's talk about the voltage on the secondary side. I have 120 volts on that coil and 120 volts on that coil. We have these two coils connected in parallel. We have X1 and X3 connected and X2 and X4 connected, putting these two windings in parallel. Voltage when it is in parallel does not change. Therefore the voltage that my voltmeter here is going to read, this voltmeter here, is going to be 120 volts. Now we've taken care of the voltages. We have 600 volts on top on our supply and our voltmeter down here is reading 120 volts. Let's now talk about the currents. The current on the primary side here. We notice that each winding is rated for a rated current of 33.3 amps. In series, current stays the same. So this transformer, because I've got 33.3 amps on both windings and it's in series, the primary rated transformer current is going to be 33.3 amps. That's my rated primary voltage and my rated transformer primary current. Our secondary down on this side, we have 83.3 amps on each winding. However, those guys are in parallel. Voltage stays the same in parallel, but what we do is we add our currents in parallel. The maximum current for this transformer on the secondary side will be 166.7 amps. So now I've determined with this connection, I have a series connection on the top side around my high side and a parallel connection on the bottom side just to recap. We take this voltage, split it in half, which is 300 and 300, so it's safe there. And we take this voltage, these two guys here, they are connected in parallel. Parallel voltages stay the same. We end up with 120 volts on our voltmeter. We have a maximum of 33 amps on our primary transformer because the windings are in series and current does not change in series. And down below on our secondary side, we have a maximum current of 166.7 amps. And that is because when windings are in parallel, the voltage stays the same, but the current doubles. So that's a series to a parallel connection. Next up, let's take a look and see how this works with a parallel to a series connection. So what we've done here is we've taken the second, the same transformer, sorry, and we've connected the primary in parallel and the secondary in series. Same transformer, except the only difference is now we can only supply 300 volts safely across this because each winding is rated for 300 volts, which means they must be put in parallel. Down on the bottom, we have 120 volts in series with 120 volts. Voltages when they are in series add, therefore this voltmeter is going to read 240 volts. So that takes care of our voltages. Let's talk about the currents now. Currents up top in a parallel, remember currents add, we have 33.3 amps and 33.3 amps. So the maximum transformer primary current will be 66.3 amps. Sorry, I meant 66.6 amps, not 66.3 amps. Okay, so that takes care of our primary current. Let's talk about our secondary current. Our secondary is wired up in series because we've got x2 to x3. Our voltages added, 120 plus 120 gave us 240, but our current when in series stays the same. So we have 83.3 amps on each winding. Those windings are connected in series. Therefore the current, maximum current on the secondary side is going to be 83.3 amps. And there you have it. We have all our voltage ratings and all of our current ratings. Now keep in mind this example is done based off of the fact that we are fully loading this transformer and that it is running at rated voltages. So that again we're using our actual ender rated as the same. In future videos I'll try to mess you up a little bit and I will use the rated and the actual and have them different. We'll see what happens with that. In our next video what we're going to discuss is how important it is to make these connections between the H1 and H3 and H2 and H4 and on the secondary side as well. How important it is to make those connections proper because if you don't you experience what I like to call a ka-blasel flam. That will be coming up in the next video.