Stamford Generator Problems

Try disconnecting the field connections from the avr, run the machine and measure the field voltage. This reading will be the residual voltage in the field. Compare what you get with the residual voltage requirement of your AVR. If it's lower, you will need to flash the field with a car battery.

If the residual is zero, you may have a blown rotating diode. If this is the case, you will need to expose the rotating diodes and test each one to find the faulty one.

Usually - if you excite with an independent source and teh generator voltage increases, then the diodes are fine. Try running up the machine, then connect a battery to the field instead of the AVR. Measure the gen output.

Good suggestions about rotating rectifier, but just be careful flashing the field with a car battery while it is running... don't do it for a long period, just a touch, or the voltage may build too high and exceed insulation limits especially if insulation may have become 'weak' in 2 years of decay from humidity or insects, rodents, etc. I once flashed the field while running (you should do it stopped first) and the spark was so intense it welded my little car battery wire to the F+ connection and voltage went off the scale until I forcibly pulled the welded wire free of F+ connection. Yikes !!!!!!

Thanks for your advice, but I already managed to find the fault, it was a defective water pump that was connected to my grid that caused all the problems.

Thanks again

AS you mentiond you bought a new Avr so the problem may be from the Exciter

winding or the rotating dides or the stator so i recommended that you follow stamford

fault finding manual in order to help you to cover all the symptoms but first you shoud

be confirm if you have output voltage or not and you can download the manual via

internet, and as a fast action you can measure the exciter winding F1 & F2 it should

be in the ange of 18-30 ohm