Delco 10SI rebuild question

Zachary Hoyt · Dec 10, 2012

I have an alternator that I am rebuilding and am missing a part. I do not know what it is or what it does. I bought a rebuild kit but this part was not included. All of the other 10SI alts I have been inside have had this part but it was missing from this one. It looks like a spring or coil with two tabs on it. One tab is held down by the screw on the brush holder that also holds the arm of the diode trio, the other end is held down by the adjacent screw on the brush holder that is closer to where the VR tabs are located. I assume it is necessary, but I have no idea what it does. Any advice will be much appreciated.
Zach

Ronald Anthony Anderson · Dec 10, 2012

If that is the one with internal regulator I have that part. I used to rebuild them and have a pail with parts I saved. You could buy a junkyard alternator for 10.00 and get a kit cheap then converted 6 volt tractors to 12 volt.
I don't remember what that part does but maybe it would connect the internal regulator to something else? The older alternators had external regulators and maybe that was what your kit was for thus no need for that part.

Zachary Hoyt · Dec 10, 2012

Yes, it is the three wire setup with the internal VR. I would be happy to buy the part from you if you were willing to find one in your bucket of parts.
Zach

LJD · Dec 10, 2012

It's a wire-wound resistor and it is not used in all the 10SIs and 12SIs. It connects between two screws on the voltage regulator and one lead of the diode trio attaches to it. If you have the back of the open alternator facing you - with the diode trio on the bottom - the one-lead end from the top of the trio goes to the upper right and attached to the left-hand lower terminal of the voltage regulator. The resistor - if used - runs from that terminal over to the other lower one on the right.

Allan in NE · Dec 10, 2012

All that resistor is for is to keep the idiot light (if so equipped) from dimmly glowing at night.

Really don't need it at all.

Allan

Zachary Hoyt · Dec 10, 2012

Thanks for the advice. This is the third or fourth I have been inside and the first that didn't have one of these, so I thought it would be too bad to hook it up to the tractor and damage the new parts in some way. I don't know how to draw an arrow on my photos like some do, so I put the two pencils in to show where it would have gone in the others I have been in.
Zach

LJD · Dec 10, 2012

Yes, those pencil tips are where the idiot light resistor would go.

Ronald Anthony Anderson · Dec 10, 2012

I know I got one but am waiting for it to warm up before going outside. -10F and 15 inches of snow and my lungs don't like cold weather anymore. Send me a e-mail and I'll send you a picture so we know it is the right thing.

Zachary Hoyt · Dec 10, 2012

Thank you very much.
Zach

Zachary Hoyt · Dec 10, 2012

Thanks for your help, it looks as though I actually don't need it after all though.
Zach

Ronald Anthony Anderson · Dec 10, 2012

I did find one in a pail in the basement lol no need to go outside yet but glad you don't need it.

teddy52food · Dec 10, 2012

I often wondered what that was in there for.

JMOR · Dec 10, 2012

(quoted from post at 12:19:02 12/10/12) All that resistor is for is to keep the idiot light (if so equipped) from dimmly glowing at night.

Really don't need it at all.

Allan

he purpose of the idiot light is to alert the operator that the alternator is not working. I believe the 40 Ohm resistor in question does a little more than kill a dim idiot light at night. Take it out and the idiot light will NOT light when alternator has zero output as a result of a regulator failure which causes no field current. With it present, the idiot light will illuminate under this condition.

rodm1 · Dec 11, 2012

Where did you get the rebuild kit?

Bret4207 · Dec 11, 2012

Idiot lights glow during the day too. They can't tell the difference, the idiots!

Delco 10SI rebuild question

Zachary Hoyt

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Ronald Anthony Anderson

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Zachary Hoyt

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LJD

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Allan in NE

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Zachary Hoyt

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LJD

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Ronald Anthony Anderson

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Zachary Hoyt

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Zachary Hoyt

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Ronald Anthony Anderson

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teddy52food

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JMOR

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rodm1

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Bret4207

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