Transformers 101: How They Work

 How do transformers work? Which ones should you use and how do you test them? So let's start with how they work. So basically you have two sides to a transformer, the primary coil, which is where the voltage goes in, and then the secondary coil. The second coil, which is where the energy goes out. So you have many types.

Some will have multiple uses. We call 'em universal transformers sometimes. Or you may have one that specifically has only two wires in and two wires out, and you could use either one as long as you use the right one. Now on here, all you have to do is look and see which wire is common, and that means what it has in common is all of these wires.

Have to use this one when you use one of them. Okay. So you have to, of course, read the label. I say that all the time. You can get the same transformer, part number out of a, uh, from the same supplier, and one will have a different color, common wire. So we have to read and make sure, in this particular case, common as black.

So now. If I go black and then red,

it would be, let's start here. It would be black and white. That's 120 volts. Okay, so if it's not 120, I don't need the white wire. If it's 208 volts, I use the black and the red wire. If it's 240 volts, I use the black and the orange. So if you don't need to, just cut them off, put a wire nut on them, tape them up, and that's it.

Now, uh, how this works is you have a magnetic field. It's called magnetic inductance. And basically, if you've ever taken two magnets together and you know how you can feel them, uh, tracked or repel, well, there's energy transferred while they're not actually touching. And the similar thing happens inside the transformer.

So you have voltage go in here. It goes through a metal coil that's wrapped. It creates a magnetic field, magnetic conductance, and then the coil on this side is smaller, which means it goes from a big coil to a small coil, and it steps down the energy. That's called a step down transformer. That's what this is.

So you have 240 volts going in, or 24 volts coming out. If you use the black and white, you got 120 volts coming in and then 24 volts coming out. Now, of course the voltage coming out will won't exactly be 24, 26, 25, 23, that's all. Okay. There's a pretty good range in the components that you use in the system, so as long as it's in the neighborhood of 24 volts, you're good to go.

Same thing here. Not every house has exactly the same voltage. It could be 2 35, it could be 2 38, it could be two 20, so. They do allow for a variance and they are supposed to be a little warm when they operate because the energy going through them will dissipate as lighter heat. And since this doesn't give off light, it's gotta give off heat.

So energy in this side comes out that side. These two sides should never have continuity between them. And we'll show you how to test them in just a minute. But when you buy them. Make sure that you look at the ratings on them and you match the ratings of the one that you took out to the one that you put in.

So voltage in, voltage out, high voltage in, low voltage out, which means it steps down and it transfers the energy through a magnetic field. And that is how a transformer works.