Alternator Conversion

WGM · Jan 3, 2009

I"m in the middle of replacing the generator on my Minniapolis Moline UB with an alternator. Saw several posts about connecting the #1 terminal of the alternator to the "load" side of the ignition switch. Would this be the same as connecting to the + terminal on the coil? It would be controled on-off by the ignition switch and would technically be a load. Thank you in advance.

john in la · Jan 3, 2009

In reality even if you hook the #1 wire at the key switch it is hooked at the coil because the coil wire hooks at the same place.

What you need to remember is the #1 wire must have some form of disconnect other than the key. A one way diode; idiot light; something. If you do not provide this one way for power to travel the alternator will supply power to the coil even after you turn the key off and you will not be able to turn the tractor motor off.

johndeereman · Jan 3, 2009

no diode needed i hooked me dc case up this way no switch at all go from # 2 post to batt post on alt. then go from batt post on alt to amp guage then from guage to batteryworks just like a 1 wire alternator dont use the #1 post thats what drains the battery ive had this hooked up this way 2 years never a dead battery unless i run it dead with starter lol only thing is you have to rev engine to excite the alternator but you have to do that with a 1 wire also so whats the difference other than pricemost gas tractors rev high enough but if it dont just use a smaller pulley on alternator or bigger on tractor which ever im sure someone will find fault with this but works for me hope it helps you

ken in texas · Jan 3, 2009

Ihooked the sense wire to the lights side of MM switch on UBSpecial(i don,t use lights)It will energise the alt. ,and once charging you can turn switch back to ignition(these MM.s don,t have keys,only a switch.Also lots of opionions about about converting 6volts to 12 volts,but when we had a new UTU MM 1952 on 6volts and propane,it would hardly turn over in cold weather and would have to pull start it.Later Iconverted it over to 12 volt battery and 12 volt gen. and it would spin fast and start just fine.I think the UB MM were all 12 volt systems,from the factory.But the converted UTU would start easier and faster.Converted several 6 volt to 12 and always worked great.

rvirgil_KS · Jan 3, 2009

Yes, + side of coil goes to the switch so both are electrically the same.

I just recently converted my UB to Delco 3 wire alternator. I wired mine as follows:

#2 wire on alternator plug to large post on back of alternator, then from this post to both the Bat and L (load) wires from generator regulator

#1 wire on plug through a diode to the Positive + side of coil. (band end of diode toward alternator).

For Delco alternator, tractor must be negative ground and Negative – side of coil goes to distributor.

Mine has original pulley on alternator, uses same belt as generator and it starts and charges at low RPM. All automatic, no extra switches to worry about.

My email is open if you have questions or would like pictures

Bob

WGM · Jan 4, 2009

Thank you to all who responded. Finished the wiring this morning and connected to the + terminal of the coil and installed a diode as discussed. Worked perfectly.

Alternator Conversion

WGM

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john in la

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johndeereman

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ken in texas

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rvirgil_KS

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WGM

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