Thanks guys. I'm aware that in Wye configuration you get 208 volts. I don't really understand why in the Delta configuration you get 240 volts. Furthermore, how do you wire up your load in either a wye or delta configuration? Where do you put your neutral in relation to your hot legs?
To understand why you get 240V on Delta config, you need to look at this chart:
As you see:
N -> is the neutral
E -> the 120V generators.
The Vector CB, called V3 = -E1 +E2, so, The big question would be, how do you get 240? The main definition of voltage, is actually a potential difference, between two states. In this case , if you take the point of E3 as a reference (let's say it's actually the neutral, even if it isn't the neutral as we understand) and you measure the difference between E3 and E2 is actually |E3|+|E2|, and so, you get 240 V.
So, is the current flowing between one live wire to an another, yes. Why? Becasue the wires are shifted by 120°.
Delta config:
Where R, T, S are the wires coming out the generator
Where R, T, S are the wires coming out the generator.
How do you choose the configuration of the generator? It's simply given by default. Are these two the only two configurations? NO: there's also the zig-zag configuration, that's common in old equipments and it's not used anymore else:
This article here explains come things on zig-zag generators/transformers. I bet that if you get a generator that has 120/240/108 V selectable voltages it's probably something like this one. I've seen one in my life, but i've never had a chance to work on it...
https://en.wikipedia.org/wiki/Zigzag_transformer