alternator

goinbroke2 · 05-14-2025, 11:08 AM

I run master switches in everything, motorhome, bracket car, antique, Stocker. If there is a problem, I can turn the power off at the batt. (or if it's sitting for long periods)

Also, if an alternator is drawing power while not in use, you have a diode gone. You can unhook the cable or put a master switch on it, but that is a band aid to the real problem. Further, if one of the three diodes is gone and you have a batt light, you will see it flicker or come on at idle and go out when you add throttle. This also means the alternator is not putting out as much amps as it used to with three diodes.

I've never heard, and I'm trying to figure why, cutting the field wire would hurt an alternator. That is how it works, the regulator turns the charging on and off by regulating the power going to the field. It's how I test an alternator, spin it and add power to the field wire, if it charges, the problem is something else. (ford with FSAI wiring to the external regulator is mostly what I deal with)

Not saying anyone is wrong, I just don't understand how it could be a problem.

05-14-2025, 11:08 AM	#27
goinbroke2 Senior Member Join Date: Mar 2002 Location: NS CANADA Posts: 898 Likes: 1,670 Liked 395 Times in 154 Posts	Re: alternator I run master switches in everything, motorhome, bracket car, antique, Stocker. If there is a problem, I can turn the power off at the batt. (or if it's sitting for long periods) Also, if an alternator is drawing power while not in use, you have a diode gone. You can unhook the cable or put a master switch on it, but that is a band aid to the real problem. Further, if one of the three diodes is gone and you have a batt light, you will see it flicker or come on at idle and go out when you add throttle. This also means the alternator is not putting out as much amps as it used to with three diodes. I've never heard, and I'm trying to figure why, cutting the field wire would hurt an alternator. That is how it works, the regulator turns the charging on and off by regulating the power going to the field. It's how I test an alternator, spin it and add power to the field wire, if it charges, the problem is something else. (ford with FSAI wiring to the external regulator is mostly what I deal with) Not saying anyone is wrong, I just don't understand how it could be a problem. __________________ Jim Miller 103 U/SA