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.
just to make things clear...
1. I never had a chance to measure the voltage before the CPT.the 600Vac that I was talking about is the voltage being displayed in the output voltage of the generator pannel.
2. We used 2 CPT connected open delta. and the unbalance low voltage that I am talking about is the voltage across the sensing leads, connected to the AVR's sensing voltage terminals.
It appears you are going full field until the thermal limiter in the AVR trips, so if you are putting 80 VDC into the field, and you have 600 VAC at the generator terminals, then it sounds like you have sensing problems to the AVR.
On the face of the VR3 there is a tag with its part number, and sensing voltage rating. You need an appropriate set of open delta PT's (CAT's standard connection) to take the generator terminal voltage and step it down to the sensing voltage so the system will work correctly. Typical CAT application is 480 to 240 VAC PT's, but there are other possible configurations.
It appears you have started another thread to test the rectifier and surge suppresor, you really need to get a copy of the service manual for this generator if you are going to work on this yourself, it is CAT publication number SENR5359.
