?First, I would note all the different voltage standards are arbitrary, originally stemming from decisions made way back by Edison and Tesla in the original electricity wars.? Most people think that 230v is a better baseline standard, and that's what Europe has because Europe was actually behind the curve.? We have 120v standard in the US because it's compatible with Edison's original somewhat random choice, not because it's inherently great.? Europe started electrification later than the US, and by that time, 230v was understood to be a better choice.? It's a lot like metric vs imperial vs whitworth.

That said, two physics principles warrant pointing out.? First, three phase motors are superior to single phase? -- more efficient, self-starting, smoother.? ?Four phase or six phase or eleven phase (all real things) motors are smoother yet, but for various practical/cost reasons, 3 phases was the most practical early on, and became the common industrial standard, in parallel to the 110v single phase standard for lighting that began Edison. The second basic physics is that higher voltage allows smaller conductors.? So the higher the wattage (total power), the higher the voltage you want, in order to minimize the wire/infrastructure cost.? ?At 250,000 volts, the wire size you use on your Felder saw could power a neighborhood.

So generators (hydro dams, coal-fired, etc) produce three phase at very high voltages (250kv), and it gets transformed down to "usable" voltages the nearer it gets to the point of use.? At my day job we get 12kv from the utility, which we transform down on-premise to various voltages, ultimately to 120v for "consumer" devices.? But most small/medium industrial users get 600v, because above that it's more complicated to manage.? ?Once you get much above 600v, air is a conductor, so for example breakers have to have operate in a vacuum, or other such complexities.? ?You don't casually turn things on and off that operate at kV levels.? So although you might save money on smaller wire by having 2,000v motors vs 600v motors, you pay a premium in other other ways for higher voltage.? We have more electrical safety personnel than electricians doing electrical work.

So to Brett's point, every industrial facility needs both 3 phase (for motors, etc) but also has toasters and coffee pots.? And so electrical distribution systems evolved to conveniently supply both the local standard 3P voltages (600, 500, 480, 460, 400, 240..) and the standard single phase voltages (120 or 230 almost everywhere.)? It's very simple to get any voltage off a transformer, it's really nothing more than the number of wire windings.??

To Brett's comment that neutral is "manufactured".? Well, every output of a transformer is "manufactured".? That's what a transformer does.? It's a device to manufacture some voltage different than the input voltage.? So if you have a transformer with 600v input, and you tap 240v out, and also 120v out, they are both manufactured.? ?But it's correct that it's always the last step, for practical purposes.? If you step down to 120v a mile away from the point of usage, the conductors to go the "last mile" are impractically large and expensive.? So typically a residential power pole is carrying ~5kV until the transformer that you see on the pole outside your house, which steps down to residential voltages.

In this sense, "manufactured" is different than this word is most often used on FOG, ie, in relation to phase convertors.? A phase convertor manufactures a phase shift, not a voltage change.? It takes voltage in that is 180° phased, and shifts to 120° phased, basically by storing electrons for 60° of time, and then releasing them.? ?

To illustrate the independence of phasing and voltage, here's one of my three phase motors.? It's 5V.