stickman77

I currently have an externally regulated 10DN alternator and want to upgrade to a 12SI internally regulated alt. My voltage regulator is a 2 wire, not a 4 wire. Can anybody tell me how to do this conversion properly

MDchanic

2-wire regulator? No such animal, as far as I know.

Pictures.

Welcome to ClassicOlds.

- Eric

joe_padavano

As noted, there is no such thing as a "two wire" external regulator for GM, but that's irrelevant. Find the brown wire from the GEN light. Connect it to the #1 terminal on the 12SI. Run a wire from the horn relay stud to the #2 terminal on the 12SI. Run a heavy gage wire from the horn relay stud to the BATT stud on the 12SI. Done.

stickman77

Here is a picture of the plug with only 2 wires.

stellar

Check out this animal. Never say never. GM wiring circuit for Delco regulator number 1119511. I believe these were used on very early GM (not sure what apps) 62 63 64 maybe? It looks like he will need to add a resistor from the switch as there is no indicator lite and only an amp gage . The sense wire can be from whatever point he likes.

MDchanic

It's missing its Light (and excitor) and Rotor wires.

It can't work like that.

If it is working, I would like to see how the terminals are jumped on the back of the regulator, and how they're connected on the alternator.

Anyway, connection of the 12si is simple, as Joe said, but in your case, I would ignore the existing wires and run new wires, because someone did something there that was very unusual, and you can't tell what else they might have done.

- Eric

joe_padavano

That's the wiring for a GENERATOR, not the 10DN ALTERNATOR. "Never" still applies.

stellar

better pic

joe_padavano

Sorry, still not a 10DN alternator. That's exactly the circuit that was used on my 62 F85 with the original generator. It's also NOT what the OP has on his car.

stellar

Joe check out the diagram. No diodes in a genny. This is for a Delco regulator number 1119511 used with an alternator. Remember this is soon after the switch from gen to alt was made. Note the reg is a single winding unit, similar to what chrysler used at the time.

joe_padavano

You're right, sorry. I was not aware of this version. Apparently used on cars with ammeters.

stellar

It sure looks like 2 wires on the reg to me. Open the reg to see if it is one or two coils. If only one it is wired correct. and there will be only one wire going to the alt plug. What year and model car is this?

MDchanic

Joe, as Stellar notes, that's definitely an alternator, and it's definitely got two regulator wires (while the generator cars have three).

That being said, Stellar, I just checked, and the 1961 and '62 both show generators, while the '63 shows the other oddball 3-wire regulator:



I suspect that that 2-wire oddball must have been used on some other GM car, or possibly for such a short period that it somehow didn't make it into the manual.

Either way, his photo seems to show a new (replacement) 4-wire regulator with only two of the wires connected (Field and +12V), and not one of the unusual regulators.

Guess it might help to know the year and model...

- Eric

joe_padavano

The 1119511 was used on Pontiac Tempest, among others. Note that the terminals on the underside of the 111951 that I posted above do not match the schematic in Eric's post. Two of the three terminals are ganged together.

MDchanic

Yes, definitely a different regulator than the half-year '63 system with the separate warning lamp relay.

So, Joe, from your photo, it looks as though the 2-wire regulator looks the same as the 4-wire unit, except that it's missing the #2 "Rotor" terminal.

- Eric

stellar

Here ya go Joe. A couple more diagrams. Note the 1st one. This reg even looks like a gen reg in size and shape. I think this was the 1st type used after the switch from gen to alt with a lite. I helped a guy with a 62 chevy that used one of these and it was stock .

stellar

Some late 62 had an alt. Some late 68 s had an internal reg where everyone thinks it was used 1st in 69.

stickman77

Its a 1965 grand prix, 389 car, with a factory ammeter. The reproduction engine harness sold by M&H lists 2 wire and 4 wire versions for my car if this helps
thanks

MDchanic

Just connect the 12si as Joe suggested, big red wire to big red terminal, and #2 wire to horn relay post (voltage sensor at power distribution point).

The #1 wire typically goes through the GEN light bulb to the IGN terminal of the ignition switch, but since you've got an ammeter and not a light, I would connect it to a decently heavy (at least 3W) resistor of about 10-15Ω, and from there to the IGN terminal, to provide the exciter function that gets the alternator alternating at low RPMs.

- Eric

stickman77

It appears for a '65, there are 2 voltage regulators listed. One for a light (4 wire) and one for a ammeter (2 wire). My car has an ammeter, so the 2 wire appears to be correct for my setup. Would one of the conversion adapters that quality power alternators sells work for my set up?

stellar

So Joe had it nailed as a pontiac. If Stick operates it without the exciter wire it will still charge, but I would recomend you follow Erics advise with the resistor.

MDchanic

Not that I can find on their page.

They do have a converter that would allow you to connect the 10dn plug to the 12si socket, but at $25, plus shipping, it's a whole lot more expensive than just buying a plug from RockAuto ($1.40), or your local parts store (Standard Motor Products HP3870), and you'd have to rewire it anyway.



- Eric

joe_padavano

So if you have an ammeter, you have two concerns.

First, does the output of the 12SI exceed the rating of your ammeter? Most ammeters were either 30A or 60A. If you install a 12SI of 63A or higher output, your ammeter is now a fuse.

Second, you still need the exciter wire, as noted. If you don't have a GEN light, you need to run that wire from the #1 terminal on the 12SI through a resistor (about 35 ohm is plenty) to a switched 12V source.

MDchanic

I just re-checked the schematic, and, yes, the ammeter is wired in series like it should be (It's not inductive like the old F_rd ammeters, or running with a shunt).




But, accuracy and tolerances being what they are, I would suspect that a nominal 63A alternator would be fine with a nominal 60A ammeter. I just wouldn't go any higher than that.

- Eric

olds 307 and 403

Interesting, not very often Joe gets stumped. I am pretty happy with my Summit chrome 70 amp 10 DN alternator. The performance tag said 51 amps at idle and 82 amps at cruise. I would assume it would be too much as well. Make sure you get an actual 12si case, the 100 amp 10si alternators don't last.

joe_padavano

I know Oldsmobiles, but I don't claim to be expert on other GMs. I've never seen an Olds with this regulator, and I've not seen one in the wild before.

stickman77

Guys, if i decided to just upgrade the 10dn from the stock 42amp to a 10dn 63 amp, would the stock wiring and ammeter be able to handle the extra amps?...I can live with the external voltage regulator setup for now. The internal alt conversion with my ammeter setup is a little more than I want to tackle right now

-Stick-

joe_padavano

I doubt you can plug a 63A 10DN into that two wire regulator. You'd need to re-wire for a conventional four-wire regulator. It is MUCH easier to simply hook up a 12SI. Unplug the old regulator and alternator. Connect the wire that runs to the threaded BATT terminal on the old alternator to the threaded BATT terminal on the 12SI. Connect the #2 terminal on the 12SI to the BATT terminal also. Splice a 25-35 ohm resistor onto the wire to the #1 terminal, then run a wire from the other side of the resistor to the old regulator connector wire that did NOT connect to the alternator. Done.

When done, it will look something like this:

MDchanic

Aw, c'mon, Joe. At least have him run the sensor wire to the horn relay post.
Looping it back to the output stud is so... Geep-y.

- Eric

stellar

Some Cadillacs had the sense (#2) wired from the factory directly to the output post as shown in Joes pic.

If he replaces the 10DN stator with a 63 amp stator and retains the original rotor he can still use the original regulator. I doubt if a rotor for a 63 amp would damage the reg, but I'm not 100% certain about that. I don't think a wiring upgrade is necessary up to 63 amps.

If he wires a 10SI 63 amp, he can run without the #1 wire and use only the #2 and power connected to the output post as shown in Joes pic and it will function like a 1 wire alt. The #1 can be empty. I think this would be the easiest and least expensive. It would also allow him to retain all the original wiring with no cutting in case he should ever want to return to original setup.

joe_padavano

The method I suggested doesn't require cutting either. The field wire from the 12SI plugs in to the old regulator connector with a spade terminal. The sense wire attaches to the threaded post on the horn relay.

stellar

You lost me Joe. Do you mean connect without a resistor?

joe_padavano

You were suggesting ways to not cut the original harness by not using the field wire. My point is that with a 12SI, the field wire that I showed with the resistor simply plugs into the old regulator connector at the wire that did NOT run to the original alternator (the one that goes to the switched +12V source). Use a male spade terminal on the wire with the resistor and no irreversible mods to the original harness are required. The other two wires go to the junction on the horn relay.

stellar

got it thanks.

ReallyWildStuff

What would happen if you ran an externally regulated alternator without a regulator?

https://flic.kr/p/QVbgD3

If you can zoom in on the upper left hand corner of this test stand setup (onto the back of the alternator) - the '84 (12SI Alternator) plug didn't fit in the alternator so I had to make a temporary conversion harness...that means its a 10DN alternator, correct? And that means it needs a regulator - right? What happens without one?

I'm sorry all my posts sound like "Why is there air?" or whatever but...I got this alternator from a friend just to test. It didn't even occur to me that it could be externally regulated.

I had the voltmeter on the system when I had it running and it seemed to put out 14.4 nuts on the whole time...

MDchanic

That is a 12si alternator. It is internally regulated. It does not need a regulator.

- Eric

ReallyWildStuff

Thanks. The pinout on the spade terminals ("1" & "2") does appear to match that of a 12SI.

What to make of the fact that the white/red molded plug doesn't physically fit into the reliefs in the top of the case housing? Perhaps I have a a "10 SI" - internally regulated, but the plug is of a different configuration?

http://alternatorkit.com/alternators.html

The vent holes on mine match the 2nd 10SI image in the link above.

For comparison - I see that on the 10DN the connections are made from the back (not the top) and are labeled "R" & "F". Also that the back of the 10DN case is markedly different from the SI series.

joe_padavano

The 12SI is just a newer, higher output version of the 10SI. They are functionally, dimensionally, and electrically interchangeable (allowing for amperage differences). Both are internal regulator designs.

MDchanic

The alternator in the photograph is a 12si.

I don't know what setup you may have on your car, but we could tell you more if you could post a few more pictures (and actual pictures are better than Flickr links, as it is tough to find the actual url of the photo within the page's code).

- Eric

ReallyWildStuff

I will get better photos tonight. I obviously don't _know_ (that's why I'm here) but I would still like to find out why the plug won't fit.