the things on power lines. we recently had two power outages, and it was because the “transformer blew up”. what does that mean exactly?
In: Engineering
Electricity is the flow of electrons under pressure. If you want more energy, you can use more electrons *or* more pressure. There are upsides and downsides to both.
High pressures (voltages) are way more dangerous, but lose less energy over long distances. More electrons (higher amperages) are safer (and usually easier to use) but lose lots of energy as they travel.
So ideally, we’d have high voltage over long distances but high amperages where we actually *use* the electricity.
To switch between high voltage and high amperage, we use a transformer. It is only a little bit more complicated than a big spiral of wire, but the effect is that high voltage on one side is exchanged for high amperage on the other.
All conductors have some amount of resistance, even copper. That resistance means that a small amount of the current flowing through the conductor will be lost as heat. Transformers are designed to deal with some amount of heat but obviously have a limit. Once that limit is reached the transformer can fail, sometimes dramatically.
The other poster explained really nicely why transformers are used, but since how they work is relatively simple too, might as well touch on that.
A changing electric field generates a magnetic field. A changing magnetic fields generates an electric field. That’s the basis of how electric generators and motors work.
But turns out you don’t need anything spinning to use that. If you put two separate coils on a metal bar and run alternating current (AC) through one of then, you can generate electricity on the other. The alternating (i.e. changing) current generates changing magnetism in the bar, which generates an alternating current in the second coil.
Now, that would be just an interesting but very niche device. BUT! It turns out that the voltage of the second coil compared to the first is related to the amount of windings on both coils in a simple relation:
You just multiply the original voltage by the ratio of the windings.
So if the first coil has 100V and the wire is wound 10 times, then if the second coil is wound 20 times it will have 200V.
The inverse is true if you have 2000V on the first coil, and 100 windings, then a second coil with 10 windings will be 200V.
So now you can easily adjust the voltage to anything you want just winding some coils around a metal core in a straightforward ratio.
You have a transformer.
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