1066 Alternator Replacement

1130Leo · Jun 5, 2014

I noticed the bearings in the alternator are shot, when I looked up a replacement alternator, noticed it said they were a "3 wire". My current installation has the 3 wire alternator, however only has a 2 wire clip connected, the third wire I found broken far from the alternator, and obviously not connected. Anyone know what the third wire is for, and should I connect it when I put in the new one?? I am now guessing this may be why none of my electrical in the cab appears to work at all.

1130Leo · Jun 5, 2014

I guess it technically is a 4 wire? The red positive bolted to the post, then 3 additional terminals on the top side. I have the shop manual, will try to find it there as well.

Bill in IL · Jun 5, 2014

Do you possibly have an early 1066 that may also have an externally regulated delco 10DN alternator. They had a 4th wire that was just a ground.

1130Leo · Jun 5, 2014

It is a Black Stripe, so it should be a later model? I have seen many delco alternators over the years, never saw one with a 3 wire connector to plug in.

pete 23 · Jun 5, 2014

A black stripe would be what we refer to as a three wire. One output wire, & two small wires together in a connector. One is sense lead for regulator, other is exciting lead from ign. Many new or rebuilt replacement ones will have a third spade where the two wire connector hooks up to. It requires a different connector to get all three terminals. That one is to run a relay on other applications or a tachometer on some machines. There are two style of brush holders in those alternators. The early alternators has sliding brush and only had the two terminals, and the later alt had a swinging brush and those had the third connector which , like I said is normally not used on the tractors. The cheap part store alternators are the sliding brush style which the vibrations from the diesel engines cause those brush's to work in their holder and get a groove and thus stick.

1130Leo · Jun 5, 2014

Pete, thanks for the info, The one I ordered to replace the existing they call it a "3 wire", now that I know the third position is not normally used, I feel better that once I install the new one, with the two position connector, it should work....

Thanks again,

Leo

Owen Aaland · Jun 5, 2014

If you know what to look for you can tell the difference between the 10SI Type 110 with sliding brushes and the 10SI Type 116 with swing style brushes.

Type 110 sliding brush

Type 116 swing brush

Note the added ribs, the additional screw, and the slotted hole on the swing brush model

1066 Alternator Replacement

1130Leo

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1130Leo

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Bill in IL

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1130Leo

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pete 23

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1130Leo

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Owen Aaland

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