How excitation happens in power plants generator? like dams

[mosta]

Hello

I tried to look for the answer but didn't find enough one for being satisfied

How excitation happens in big generators? If we produce electricity from electromagnet on the rotor, and electromagnets need electricity to be activated... and this happens by excitater on same rotor!

and this excitater take electricity from small turbine or generator and in that small generator needs power from excitater and excitater needs smaller one to provide power for it!

So, who came first? Egg or chicken, it confuses me
I understand it wrong or I miss point ?

Cheers

 

[Simon Bridge]

Have you seen:
http://en.wikipedia.org/wiki/Excitation_(magnetic)#Excitation_in_generators
... you don't need an endless chain of exciters (note: not "excitator") ... you only need something turning the crank.
In self exciting generators, when the generator is off, there is some residual magnetism in the iron cores that is enough to start it off. Presumably the very first startup used a permanent magnet exciter, or connection to another working generator. (It's called "field flashing".)