what is the difference between the two wires in an AC circuit, if the current is constantly switching direction? E.g. why do they say to always put the switch on the “hot” side?
In: Engineering
Lets say you have a waterwheel. Water comes down continuously in one direction to turn a wheel for you to do useful work. That’s like direct current.
Lets say instead of water continuously flowing in one direction, someone is creating waves in an unflowing stream.You have a float that bobs up and down in the water that you use to do useful work, like say every time the float moves up, you have it push the teeth of a gear up a step, then when it moves down, it moves down a tooth on the gear. That’s like alternating current.
Moving the float takes a bit of energy away from the wave. It won’t be quite as high as it was further down from the wave maker, but it still has energy. That’s the ‘cold’ side of the wire in this analogy. It doesn’t have the same peak voltage or wave height as the hot side, but it still has energy that can be put to use further down.
Because the neutral side is connected to the earth and the ground wire, so if you touch that, nothing happens even if you are standing on the ground, but if you touch the hot, suddenly there is voltage between you and ground, and current flows
One of the wires switches from trying to push to trying to pull electrons. The other wire is by itself often inert. Those are hot and neutral respectively. There is also the possibility to use another hot wire that’s always in the opposite phase of the push-pull cycle as the other wire, which gives you double the voltage (that’s how 240V outlets work in the USA).
Yeah, you’d get a single 240v phase. But if that’s what you’re after and you are willing to use a transformer then a step up transformer starting with a single phase would be so much simpler. The draw of hacking together 2 extension cords is you can get 240v with just a few bits of wire and wire nuts. It’s cheap and doesn’t require any extra components.
What all of this won’t get you is 240v 2 or 3 phase power though. Which is used in non-residential things. So if you have some industrial machinery that has a 240 3 phase motor you’d need something entirely different.
So in summary there are very few situations where hacking together your split phase power is even useful and if you are going to use a transformer then a step up running from a single phase is the best answer anyways.
Edit: like this https://www.amazon.com/dp/B000MX50KA/ref=cm_sw_r_cp_awdb_t1_80OWEbD9CTD87
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