Thanks for the reply sir,ok to give you a final hint....
1. When the exciter stator is not connected to the F1, F2 the sensing voltage terminals reads... up to 12Vac, and the F1 F2 reads....48Vdc.
2. When I connect the exciter stator to F1 F2, the generator starts to build up voltage and goes as hig as 600 Vac. During these stage measuring the sensing voltage terminal it reads...an unbalance 25, 35, 15 Vac. and F1 F2 terminals reads...80Vdc.
It seems that I am getting a 600 Vac from the terminals of the generator, but I have an unbalance low sensing voltage input on my AVR.