A three-phase power supply can be illustrated by three separate generators linked together, each completing one third of a power cycle while pushing and pulling electricity. Understand a three-phase power supply with interesting information from a math and science teacher in this free video on science.
Hi, I'm Steve Jones. I'm going to tell you a little bit about three phase electricity, and why we use it. Well, in your home, you don't use it. You use single phase electricity. You use electricity, which people will draw, like that. That is, it's alternating current, and the current is going backwards and forwards. Now, if you build a generator, to generate single phase electricity, it will last five minutes, and then explode. The reason being, that when you're generating this electricity, at this point you're generating electricity, at this point you're not, so the poor old machine is generating, then not generating enough, and it shakes like crazy. That is not a good idea, but if you are very cunning and you arrange three electric generators, and connect them together, you will generate like this. For one of them, you'll generate like that, for the next, you're generating like this, and the next, you're generating like this, and at any time, the machine is doing the same amount of work. In fact, it's doing nothing essentially, because for these two, it's pushing power in. This one, it's pulling power out, so overall, there is a balance of power being generated, so the generator, instead of pushing electricity and stopping, pushing, stopping, pushing, stopping, it is simply doing the pushing and stopping, but three different ways, and in three different phases. When we use the word phase, we mean time, and the time interval is one third of a complete cycle, and each starts a third of a cycle later, and therefore, the balance is maintained. This ensures that your generating machine, whether it's a diesel generator, or whether it's a major turbine, in a huge pastation, it's generating all the time, an equal amount of energy is being used all the time, pushing the energy down the line. Well, you of course, in your house it doesn't matter. You're only using a tiny little bit of electricity, and therefore, you're just using one of the three phases. If you're in a factory, you'll find that all three phases are used on one machine, because the machine might be quite powerful. If you get an imbalance of the use of each of the three phases, you'll find the machine generating it, will shake, vibrate, and eventually break down, so make sure you balance your three phases, but at home don't worry, it doesn't matter.