Tanel you know for a fact I would have you here. The big thing about electricity is understanding the difference between AC/DC which is really just the waves they produce. AC produces are curved wave. While DC produced a square wave.
Discussion
wait
what is a curved wave and what is a squared wave?
So an AC wave is like this one: essentially this is what the electricity coming out of your walls looks like but most likely in 3-phase: meaning there is 3 of these lines intersecting to prevent a drop(when the line crosses the x axis) in voltage. 
While a DC wave looks like this: this is what comes out of batteries. 
Also I am tarded tanel