My NH 3930 alternator is a Delco-Reny and when it went bad I had it rebuilt by a reputable shop. The tractor battery light will start flashing after approx. 20 minutes of running. I checked the voltage output and it read 14.7. I bought the tractor used with only 430 hours and it now has 940. This tractor only has two wires to the alternator(battery & sending unit). It doesn't have the battery over heat sender. It also has an internal regulator. The only thing I have found are three wire units. Any help will be appreciated.