All right, so I want to do a quick video and describe transformers how they work some practical things for air-conditioning technicians and then we're also just gon na pull it apart, see what we can find. I've never actually pulled on the part completely myself. So we'll see what we get out of this thing, but the first thing is that this is a multi-tap primary transformer. What that means is the primary is the part where the voltage and current comes into the transformer, and so we've got multiple tabs.

So I'll show you what that means in a second, but then this only has a single secondary. So this is the part that that comes out of the transformer. From a really simple standpoint, a transformer is an electromagnet and it actually uses electromagnetism in order to transfer current from one side to the other, and we use a transformer generally in order to change the voltage one way or another. So this would be a multi-tap primary step-down transformer, so it's going from one of these incoming voltages, 120, 208 or 240 down to a fixed secondary, which is 24 volts, so either 120 200, a 240 from the primary down to 24 volts really easy to wire.

On the primary common is white, so it gives you the color code right here. Common is white, so we know we're gon na use the common on the primary. So we know we're gon na use white, and then we choose one of these other three colors based on whether it is 120 volts, four black red would be 208 and orange would be 240. That's what we're limited to on this transformer.

Another piece of information here is: this: is a 40v a transformer. That's a 40 volt amp transformer, since it has a 24 volt secondary. If you do the math. That leads to one point: six: six amps.

I think if I remember correctly one point: six six amps is what can be drawn on the secondary before you're gon na run the risk of overloading the transformer, so volt amps is volts times. Amps equals volt amps. So that's how you calculate that, but really inside of here you just have an electromagnet. You've got an iron core that goes down the center and it transfers electromagnetic energy from the primary to the secondary via magnetism, without the two actually touching each other.

So the primary and the secondary they never actually touch they're, not directly connected they're connected through a magnetic field and known as magnetic flux. So because both of these wrap around this iron core, that's how the energy is transferred and you'll notice. If you look at this, it almost looks like there's two coil stacked on top of each other, and I think we're gon na find that that is what we have inside here again, I'm not really sure to pull this apart before the number of rat on the Primary versus the secondary is what dictates whether it is a step up or step down and how much and so it's a ratio. If you look at this secondary here's 24 volts and if we wire this up for 240 volts, that's a 10 times divisor 10 times multiplier, which means that in this case you have 10 times the number of raps on the 240 side wraps of little copper wire.

If you look inside there, you can kind of see some of that shiny, copper in there, because that's really what drives this thing! That's! What drives this electromagnet there's 10 times as many wraps on the primary, but at the 240 volts as there is in the secondary and that's what causes it to step down. So just as a you know, a round number, let's say: if we have a hundred wraps at 240 volts in the primary that means we would only have 10 wraps on 24 volts on the secondary and then each one of these. You know this is a 5-time multiplier would be 120 and then 208, so you don't write it between there, we'll say: 7 for the sake of a round number 7 and 1/2. That gives you an idea of how this works.

This is rated for both 50 or 60 Hertz, so it works in the US or in Europe. Another thing to notice about this transformer, these 40v, a this is what we'd call you know a universal transformer. This is one that we keep on the trucks for repairing air conditioning on the secondary. There is no fuse in this, and so some transformers come with fuses built into them.

This one does not, if you don't, have a fuse and the secondary anywhere else, and you would need to put a fuse in and all you would have to do is just you know, connect one end to a fuse. You should typically use a little 5 amp fuse, so this is a little 5 amp fuse that bood use and a lot of air conditioning applications. Some cases you use a 3 amp fuse, but 5 amps really common, and you can install that in line on the hot legs. You just connect this to one side using a Spade connector and then connect the other side out to the r terminal or under handler or furnace or whatever, wherever it was connected before, and then that provides some fuse protection, they're obvious if you're gon na do this Manually make sure you make good connections, make sure that they're insulated all the way that there's no exposed wire.

That sort of thing, but I found myself needing to do that on many occasions. So now I'm going to go ahead and start pulling this thing apart and see how easy it is to pull apart, and maybe maybe I need a hacksaw. So I'm going to start with these little tabs here on the bottom. Now, let's see if this will pull off here there we go.

Bottom fell off sides on top coming off pretty easily here, yeah, absolutely it in place. Alright, there's our iron core wraps around the outside, and then it goes into the center and let's go ahead and pull this wrapping off first and then we may need to cut this thing with uh the hacksaw or something were to get in there further. These are soldered into tiny, little wires, tiny little copper, wires, they're, just wrapped around and soldered and isolated from each other in that way, and that's where taps into different points in the primary of that transformer. Obviously, you know in order to get 10 wraps, it's got to be the full length and then five would be.

You know, half as many wraps and so depending on, where you connect. That depends on whether you're connecting you know, beginning to end or whether or not you're, you know tapping in somewhere in the middle, and so the common side would be one end and then the other side would be 240, which would be the other end, which would Be the full you know ten times wraps and so there's some variability there. But if we can I check on this other side, we should see either you know. Doesn't you don't have those multiple options, because you're limbing that one you have one secondary cut to this? Really easily carefully yeah, so you can see this is where secondary wires, end and you'll notice.

Something interesting, which is that the secondary has much larger gauge wire and without going into that too much of why that is, you have higher amperage on the secondary, because the voltage is that much lower. So if you kind of work, Ohm's law backwards or actually Watts law backwards, based on the volt ampule you'll, see that your amperage is going to be much much higher on the secondary, which is why the winding size is also a lot larger. It has to be able to dissipate that heat. That's mostly all there is to see there.

You've got two electromagnets two coils of wire one stacked on top of another. You have the smaller coil on top here. That's connected to the secondary, got a larger coil here. On the bottom, that's connected to the primary because it has to have more wraps of wire and you've got an iron core that they both wrap around.

That's really it. These do not touch each other they're insulated from each other. The only way that they transfer energy is through the electromagnetic field that travels through this iron course is, what's called an iron core transformer. So what I'm gon na do now is I'm going to put this thing in a vise and I'm gon na cut the top off of this.

I'm probably gon na damage the secondary part, but I want to get it open so that I can show you how it functions as an electromagnet using just a primary side all right, so I learned a couple of new things. I learned that these do not cut very easily because they're made of laminated steel plates that are all laid into each other like this cutting this hoping. I would have this nice intact, electromagnet that I could show you it's lifting force, because you could, you know, potentially have the coils here and you could lift up if you energized it, but that's not how this is going to work, because these are all just coming. Apart, that's what's inside a transformer, this is kind of cool, though in the process of taking it apart, the primary windings all came disconnected because if health in the wire is so they just pulled right out of the solder or broke off, you can see right.

There broke off the solder, but it's exactly like we, we figured it's just wraps of wire and it's got this plastic core, so I thought I was gon na be able to separate them, but I can because they were just wrapped around this plastic core she's, actually Kind of surprising, because that play are plastic acting as a thick of an insulator as that is to the core, does have to reduce the efficiency a little bit. But I imagine in manufacturing these are quite a bit easier to spool. But if you were to counsel a number of wraps on this side of this side, you would have 10 times more wraps here. Also, you know it's smaller winding.

Like I mentioned, and then you'd have 10 times less wraps here on the secondary. I can see the secondary stayed connected because the wires are a lot bigger and connecting a lot better. Another note with transformers is that when you find one, that's failed, it's interesting to disconnect it and then own out the primary and the secondary and see which one is open, because when they fail there, they're gon na fail open, eventually, even if they start shorted, they Eventually will fail open because the things melting and depending on whether or not it's an open secondary in our open primary gives you a pretty good indication of what happened to it. If there was a line side power problem, then it will often result in failure of the primary side and if it's the low-voltage side that had the shorter issue that will show up usually in the secondary side, there's another little thing you can do.

But you know it's always fun to pull things apart, see what they look like in the inside, that is the inside of a 40v, a universal residential HVAC transformer thanks for watching talk to you next time.