Edde Posted March 25, 2011 Report Share Posted March 25, 2011 Hey folks, sorry to post this on BS but time is rather critical here. I need to mount a 3 wire alternator on a small diesel motor (tractor) that uses an external regulator. Can someone carefully explain to me what to do? I know I need a beefy wire from the charging post back to the battery with a fusible linky - of what size I don't know. It's only a 35 amp alt. Beyond that there's something about jumping this connection also to one of the other alt terminals. (?) And I assume a need to get the external regulator out of the loop. Simple right? Halp! Link to comment Share on other sites More sharing options...
wrngwae Posted March 25, 2011 Report Share Posted March 25, 2011 (edited) if its a gm style 3 wire,,,,one for charging and the two on the side. one is for a idiot light and the other to excite it. just do a jumper from the big charging post to one the one that excites it. i forget which one does but it wont hurt if you do it wrong it just wont charge. you may have to rev the motor a little to make it start charging. and yes run a 10guage wire if you got it, from the back of the post to the battery direct. check with a volt/ohm meter if ya got one. btw gm's are internally regulated just in-case you weren't too sure. Edited March 25, 2011 by wrngwae Link to comment Share on other sites More sharing options...
ucw458 Posted March 25, 2011 Report Share Posted March 25, 2011 A better way to do it would be to run the excite wire to the coil + or ignition switch. Just jumpering to the bat positive will drain the batt when it's off. Oh and you don't need a fuseable link or any other fuse. Just run the charging terminal directly to the batt + Link to comment Share on other sites More sharing options...
wrngwae Posted March 25, 2011 Report Share Posted March 25, 2011 A better way to do it would be to run the excite wire to the coil + or ignition switch. Just jumpering to the bat positive will drain the batt when it's off. Oh and you don't need a fuseable link or any other fuse. Just run the charging terminal directly to the batt + your right, i put mine on my diesel tractor,,,no coil and didnt want to dink around to find the key switch +,lol Link to comment Share on other sites More sharing options...
ucw458 Posted March 25, 2011 Report Share Posted March 25, 2011 your right, i put mine on my diesel tractor,,,no coil and didnt want to dink around to find the key switch +,lol Oh yeah, diesel.... missed that part, oops Link to comment Share on other sites More sharing options...
Edde Posted March 25, 2011 Author Report Share Posted March 25, 2011 Thanks fella's. Confirms pretty much what I've been reading. To be clear I will need to go ignition switch to avoid draining the battery? Link to comment Share on other sites More sharing options...
ucw458 Posted March 25, 2011 Report Share Posted March 25, 2011 Yes run the wire to the ignition switch. The excitor wire needs to be energized only when the engine is running. Otherwize it will drain the battery while the engine is off. Link to comment Share on other sites More sharing options...
Edde Posted April 9, 2011 Author Report Share Posted April 9, 2011 Update is that the alt was actually working. My DVM says it's putting out 20+ volts AC. So either the regulator is toast or there's a broken wire/short. Long story but this is close to an hour from me and weather has been a factor in not chasing this on the spot. The alt we had with us might have been made to fit but we decided it ought to be cheaper to find a suitable reg instead. The alt bumped into the intake manifold so grinding something was going to be required at the very least. It might have also required altering a mounting hole, I'm not certain. I've read what forums I can on this tractor model but there isn't much, almost nada because it's a Japanese maker Massey Ferguson - long out of business. One guy was using a Harley regulator but the post was years old and no specific info on it. Question is... what do I need to know in order to locate a different regulator? Is it just that it's 12v output and can be mounted effectively? Link to comment Share on other sites More sharing options...
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