alternator question

Mark · Dec 10, 2009

The GM alternator on my SC was tested and showed an output of 11 volts.....so I bought a new one. Now...my question is thus:

This alternator was installed before I bought the tractor and while it has one wire terminal...on the top edge there is a place for receptacle/plug of some sort and in this, there is a U shaped jumper wire. What is this jumper for and does it need to be there?

On my SA this receptacle has been blanked off with a plastic plug.

What's the differences? Thanks again.

Owen Aaland · Dec 10, 2009

Without knowing what regulator is installed in the alternator it's hard to say for sure what the jumper wire does. Since you said it was a one wire set up it may have been used for either providing power to the rotor windings or it may have been uses for voltage sensing. Likewise without knowing what regulator is in your new alternator it is impossible to say whether or you need to use it.

I just looked at my electrical suppliers catalog and they show 26 different regulators to the 10SI series alternator. Voltages range from 6 to 24 volt.

JMOR · Dec 10, 2009

(quoted from post at 21:37:20 12/10/09) The GM alternator on my SC was tested and showed an output of 11 volts.....so I bought a new one. Now...my question is thus:

This alternator was installed before I bought the tractor and while it has one wire terminal...on the top edge there is a place for receptacle/plug of some sort and in this, there is a U shaped jumper wire. What is this jumper for and does it need to be there?

On my SA this receptacle has been blanked off with a plastic plug.

What's the differences? Thanks again.

re you sure it is an electrical jumper? Sounds wrong to me. But as Owen said, there are many different regulators. I would install as it came out of box (avoid modification/warranty issues) and if it doesn't work, return it.

Mark · Dec 10, 2009

Thanks for the advice.

The one I took off my SC appears in all respects like the replacement I bought. The 'bad' alternator had this little jumper wire plugged onto the 2 outside prongs of the receptacle I mentioned. The new one did not come with this jumper. I saved the jumper for 'just in case' I needed it.

I wondered if the jumper had been put on by the previous owner because some of the internal goodies needed to be 'jumped' because of using the alternator on a tractor instead of a vehicle as originally designed.

This receptacle is completely blocked off on my SA alternator.

I'll try it without the jumper and if works....I reckon I'll leave it alone. I just feared the jumper may be necessary to make the internal regulator work properly.

440roadrunner · Dec 10, 2009

The difference between these so--called "one wire" alternators sold aftermarket IS IN THE REGULATOR. This means that a "3 wire" and a "one wire" can look exactly the same.

So far's I know, this type (aftermarket "one wire") does not need anything electrically hooked to terminal one and two.

The original "real" Delco one wire setups had a plug on the side which you could pull out and rotate to change the voltage output. They are easy to spot because the plug is marked

Here, on the first one or two pages of this manual, is a pix of what I'm referring to.

http://www.delcoremy.com/pdfs/service_manuals/legacy/1G-277.pdf

By the way there is just one HECK of a lot of good info at that site, the "horse's mouth."

http://www.delcoremy.com/

Anonymous-0 · Dec 11, 2009

Here is a link to an excellent web site which will give an outstanding explanation of generator/alternator theory along with some
easy to follow wiring diagrams. I've used it many
times; huge help!

AllanC · Dec 12, 2009

I suspect this jumper is the one that powers the regulator. If you have a "one wire" regulator you don't need it. If you have an ordinary regulator it goes from the power terminal to the connection farthest from the power terminal. Hope that makes sense!

alternator question

Mark

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Owen Aaland

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JMOR

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Mark

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440roadrunner

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Anonymous-0

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AllanC

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