Hissing battery……

[mrgmhale]

Someone correct me if I'm wrong here, but doesn't the alternator require field excitation to generate voltage? In other words, with the field disconnected, there would be no output?

Billw69, you mentioned that you have another alternator on hand and you were going to try it. How did that work out?

You re correct, the field needs current flowing through its wiring/coils inside the alternator to work. The reason for pulling the field terminal is to see if the alternator continue to put out voltage higher than battery voltage. If it does it means there is a short somewhere inside the alternator that is allowing the field circuit to be getting current when it ought not be getting current. Just one of several diagnostic approaches to determining where the field voltage is coming from.

 

[mrgmhale]

You re correct, the field needs current flowing through its wiring/coils inside the alternator to work. The reason for pulling the field terminal is to see if the alternator continue to put out voltage higher than battery voltage. If it does it means there is a short somewhere inside the alternator that is allowing the field circuit to be getting current when it ought not be getting current. Just one of several diagnostic approaches to determining where the field voltage is coming from.

Where in Minnesota are you located? I ask because this coming week we are going to be in Minneapolis for a friend's 90th birthday and 60th anniversary celebration. If you are anywhere nearby I may be able to bring some equipment to help check things out.

 

[Billw69]

We’re located in Cannon Falls, however I leave for Oshkosh Wi. Tomorrow and would return home later next week. What a generous offer! I wouldn’t plan on bringing gear just yet. I’m still focusing on the possibility of a failed VR, seems to make the most sense, it won’t get to try a different one until later this week.
Where are you visiting in Mn?

thanks again, for all your help.
Bill