Winding for a Single-Phase Generator

Your question is not clear. You should supply more information up front.

Hopefully this might help....

A 3 phase alternator, with only 3 fields, uses a single coil on the rotor, energised via slip rings from a small DC source, usually a dynamo on the same shaft, via a control mechanism to keep the voltage at the same level.....

If you are supplying the power generated into the local mains, the frequency will be maintained by the outside mains (your tiny alternator has not the power to raise the frequency, only to increase the load current it supplies...), but if you are only supplying your own needs, you will need some sort of regulator for the water supply to keep the frequency stable with different loads....

well,i think you din't get wat i mean.i am now build a small hydrogenerator,which the whole generator's diameter is not more than 10cm,and the 3 phase coil winding for the stator is complicated and it need a lot of slot to make it turn smoothly.so that i am trying to do a single phase generator ,hope it will no need to make many slot for the coil winding.then i am just want to ask anyone here know how to make the single phase coil winding for the stator?my frequency is trying to make it 50hz.

thanks.....