Alternator Wiring

[kuny123]

Hello, I'm recently new to this forum, I am rebuilding a 1963 Bobcat M-444, the old motor was blown and seized solid, I took that motor out and replaced it with a 3 cyl kubota D1105 engine, put two brand new hyd. pumps on and put an orbital motor on to run the main shaft that runs the forward/reverse drive. All of that works flawlessly, the problem im having is charging the batt. On the alt. there is the main batt stud and it is connected to the starter batt wire. The other wire on the alt is a single wire white plug coming off the back end of alt. This wire does not go anywhere because i have no idea where it goes, Any Ideas? Thanks, Shane

 

[OldMachinist]

You can hook it to switched 12+ source or jumper it to the main stud.

 

[Tazza]

You can hook it to switched 12+ source or jumper it to the main stud.

I'd do the same. or even a self exciting alternator.
Do you have pictures of the re-power? sounds like it worked out well.

 

[donald73d]

I'd do the same. or even a self exciting alternator.
Do you have pictures of the re-power? sounds like it worked out well.

If you took the alt. to a rebuild shop (not Autozone or AAP) they would test it for you and tell you exactly what the wire was for. If it was a self excite then it only needs a single large wire to the starter solenoid. If it was a normal alternator (non self excite) then it needs +12 to the sense and +12 to the excite, and the voltage to the excite needs to be key switched. Maybe this is just the combined sense + excite. I do not think giving it +12 will do any harm. So try it. Also have you reved up the engine to see if the alternator starts charging? if its a self excite, it needs to be reved up a bit before it will "kick in" and start charging.

 

[jeepcreepcj]

If you took the alt. to a rebuild shop (not Autozone or AAP) they would test it for you and tell you exactly what the wire was for. If it was a self excite then it only needs a single large wire to the starter solenoid. If it was a normal alternator (non self excite) then it needs +12 to the sense and +12 to the excite, and the voltage to the excite needs to be key switched. Maybe this is just the combined sense + excite. I do not think giving it +12 will do any harm. So try it. Also have you reved up the engine to see if the alternator starts charging? if its a self excite, it needs to be reved up a bit before it will "kick in" and start charging.

I put a D1105 in my 642b. I am using the kubota alternator that goes with the diesel, so I would think yours would be the same. Mine required a switched 12 volt source to the exciter wire. Get this power from the ignition switch, when the key is in the run and crank position you should have power. It has to be switched or it will get hot if it sits with power when the motor is off and likely cause damage or fire.

 

[donald73d]

I put a D1105 in my 642b. I am using the kubota alternator that goes with the diesel, so I would think yours would be the same. Mine required a switched 12 volt source to the exciter wire. Get this power from the ignition switch, when the key is in the run and crank position you should have power. It has to be switched or it will get hot if it sits with power when the motor is off and likely cause damage or fire.

I do not think it will get that hot. I had a Kubota L225 diesel tractor and the shutoff was pull a mechanical knob to pull shut off the fuel. The key was really only used to start and provide excite to the alternator. Had nothing to do with the actual stopping the engine. So a few times I pulled the knob to stop it and left the key on, and nothing except a dead battery. Since that was pretty easy to do, I do not think they could have sold it that way if there was a fire hazard.

 

[jeepcreepcj]

I do not think it will get that hot. I had a Kubota L225 diesel tractor and the shutoff was pull a mechanical knob to pull shut off the fuel. The key was really only used to start and provide excite to the alternator. Had nothing to do with the actual stopping the engine. So a few times I pulled the knob to stop it and left the key on, and nothing except a dead battery. Since that was pretty easy to do, I do not think they could have sold it that way if there was a fire hazard.

It may not cause fire, but I wired mine incorrectly at first, and put un-switched power to the exciter wire. I realized that this was wrong when the alternator was hot to the touch even though I had not run it yet. I don't know if it would have gotten hotter or not if left longer, but either way the power needs to be switched.

 

[kuny123]

It may not cause fire, but I wired mine incorrectly at first, and put un-switched power to the exciter wire. I realized that this was wrong when the alternator was hot to the touch even though I had not run it yet. I don't know if it would have gotten hotter or not if left longer, but either way the power needs to be switched.

Hey everyone, hadnt checked forum in a while, i hooked the wire up to a switched 12v power from the key, and now i am charging 13-14 volts, however its one problem after another with this thing, I will post new thread with my other concerning problems, Thanks everyone for all the help.

 

[skidsteer.ca]

You can hook it to switched 12+ source or jumper it to the main stud.

Yes that wire need a momentary power to excite or kick in the alternator.
It may have to be a switched source or there will be a draw on that wire when the engine is off that slowly kills your battery.
Skidsteer.ca