Please Help me.
I have 3.phase AC Generator which have the following specification.
Voltage 440. volts ac
Power 4000 Kva
Cos phy .75
This generator was purchased from Reliance company from Germany in 1990. Up-to date it was working satisfactorly.To day i find some problems that as load is increasing hunting have ben seen in the voltage .I try my best to occupie this problem by vary the ncessory potentiometers but cant succed.I try to contact the supplier in Germany but not find them.AVR is built-in PID function . It had 3 phase winding at the pilot generator which have the 180 volts ac as a power supply to AVR then the output from avr is 30 volts dc at 10 ampare going to excite the main exciter which have the output ac and is converted into dc by rotating rectifiers. this dc is going to excite generator fields.Please i request all the experts to help me to solve above mentioned problem .
THANKS