The Stovebolt Site Forums The Shop Area The Electrical Bay generator to alternator

I have 49 1 ton that was converted to 12v long ago. Runs on a 12v generator. I have a newer alternator and want to swap 'em so I can use the generator in a old school hot rod (looks cool.) Do I need to buy a wiring harness? Or is it fairly easy to move some wires around and exactly what steps do I take? Do the two wires that go to the gen. get reused? etc.

piecea cake but it depends on the alternator, one wire or 3, internal or external regulated - check around here

Bill

3 wire

truck also has all brand new wiring.

it'll take a different regulator than the stock 12V - find the one that went w/ the alternator and it's nearly a direct switch - keep the old regulator to use where you use the generator

Bill

I'll keep the volt regulator and gen. together.

But doesn't an SI delco alt. have a regulator in it?

not if it's a 3 wire - this page talks about wiring - for Jeeps, but same basic setup - this shows the regulator for the delco 3 wire alt in the red truck

Bill

But red58, I don't understand, we've used this alt in two other cars without a seprate regulator. You are saying Alternators don't have the voltage regulator internal? I assumed a delco SI did because these other two vehicles worked fine. the article you sent me talks of "a standard (internally regulated) Delco SI alternator." So wouldn't an external regulator be redundant?

there are both internal and externally regulated delcos - internal is newer, and if the car yours came off doesn't have a regulator, then it's not a 3 wire, it's a 1 wire - from the Jeep page:
"The standard Delco SI alternator uses three or four wires"
"The "one wire" alternator kit that Bruce mentions in the CJ-3B Engine Conversion Manual is a slightly modified Delco SI alternator which can be simpler"

look at the Motorola diagram there and you'll see it's a 3 wire [or 4] with the same terminals as the regulator has

if it's actually a 1 wire then all it takes is hooking a couple of the wires together that now go to the regulator, but I can't find the note I had around on the details - you may be thinking it's a 3 wire because it'll have one terminal that'll go to the gauge, one to the battery [the 1 wire part] and another that goes to a nearby ground

Bill

Frank,

Much confusion exists..your thoughts are correct.

A. Single wire alternator. One wire out marked BATT. Special internal regulator that does special stuff.

B. Three wire alternator. Output wire marked BATT. Internal regulator too, not quite as special as alternator A. #1 wire to voltage source to energize field and start unit
charging. #2 wire to system to sense system voltage.

C. Three wire alternator. Output wire marked BATT. NO INTERNAL REGULATOR. Wire marked R goes to voltage regulator on firewall, tab #2. Wire marked F goes to voltage regulator on firewall, tab #F. The plug (DA) is usually different than alternator B so you can't mix them up. Sometimes the case is marked 1/R & 2/F.

Three units that look similar..ONE uses a external regulator.

When the dust settles there will be plenty of advice on how to hook your alternator up.

Stuart

Listen to atomarc. If the 2 terminals in the hole look like this: [||] ,it needs an external regulator.

If they look like this: [--] ,it is internally regulated.

I was wanting to go the opposite direction as Fbooth. Took my alternator off.
Bought a rebuilt 12V Delco Remy Gen. Was told that I would need to swap the Reg (looks period Delco Remy) for a generator reg.
Is there a link to run the casting numbers on the regulator to identify if the one I have is for a generator or an alternator?
The Delco Remy person was unable to identify.

This might help.

Frank,

I have not done this swap...only studied it. Assuming you are using a three wire SI alternator, this should work. You don't need a "new" harness, only a few pieces of new wire which you can tape or zip tie into the existing harness to look fine.

Using a new hunk of #10 wire, go from the BATT lug of the alternator to a connection point with the two (?) wires that were on the B terminal of the old external regulator. This must be a good connection! Look at post adjacent to this one in the forum. Cletis shows a picture of a nice junction block.

The DA plug has two wires marked #1 and #2. #1 must go to a source of voltage that is ON when the truck is running. This will excite the field in the alternator and make it charge. This connection can be the RUN position on the key switch, or a coil connection that is BEFORE a ballast resistor, if used. This wire can be small..maybe 14 gauge.

The wire marked #2 must go to a connection somewhere to sense system voltage. It isn't unheard of to run it right over to the BATT lug and attach it. If you wanted, you could hook it to the battery lug on the starter...anywhere as long as it can "see" what the voltage is in the system. This wire tells the alternator to GO or WHOA on its output. 20 million people will pop in hear and tell you where it is best to hook it...hook it up where you want, I'll work fine!

The remaining wires that were attached to the regulator can be taped off and left.

There is the possibility of "feedback", where a voltage generated through the #1 wire will not allow the truck to be shut off. A diode in this line usually solves this problem. I actually think you can purchase a DA pigtail that has a diode already installed...very simple.

So...three wires and you are all set. One #10 and two #14 wires pieces, some zip ties and electrical tape. Maybe a nice dash mounted buss for the main power connection point.

Be sure to save the old regulator, Joker is collecting them for the needy in Mustache, Texas!


Stuart

Rattletrap 52


I think your GEN style regulator will have three terminals..B(battery) A (armature) and F (field). I have a rig here that uses a alternator and external regulator. Its regulator has four terminal that are marked F-2-3-4.

These two regulators are easily distinguishable from each other. Was this the question?

Stuart

Rattletrap - this is the alt reg Stuart speaks of - gen reg is more rectangular w/ terminals on the side facing inward

Bill

Thanks Stuart then Bill for the visual. I definately have a regulator for a generator. Problem is, after wire brushing the casting numbers on the mounting flanges, there is a 6VN. Have to locate a 12 volter regardless.
Needeles to say, i've got a 6 volt Delco Remy if there is anyone who needs it - free.
Thanks,
-jeff

Here's a site that I found lots of useful information regarding alternators.
http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

I see many regulators on ebay calling out applications for a multitude of vehicles. But electrically speaking, if I have a 12V generator with a peak output of 50amps negative ground, wouldn't any 12V for generator work? Even if it was 30amp rated, couldn't I just fuse it for 20amps?
-jeff

yes, basicly any 12V regulator will work on any 12V generator - don't worry about having too much, it's too little that might be a problem

fuses are put on loads, not on the generator - 12V regultors are adjustable, and can be set - 12V generators are all very much the same output, the regulators being what controls how much of the output gets "used"

Bill

Jeff,

The regulator is a switch. If your generator has the capacity to put out 50 amps, and your regulator is adjusted to a max of 25 amps, the regulator will not allow your 50 generator to output more than 25 amps.

I think regulators were specific to MODELS of rigs...(just a hypothetical example) the manufacturer knew that a '52 Pontiac had A/C, rear window defroster and giant sub-woofers. This car had a 60 amp generator and needed every bit of it..so, the regulator for the '52 Pontiac was factory adjusted to 60 amps.

To get net on this tirade, the regulator might be of the proper voltage, 12V, but might not be matched to the output of your rigs generator.

If this guess is correct, the trick is finding the old fart at the electrical shop who can tweak the unit to match the gen output. Keep in mine this is all supposition on my part, I am a not generator guru!

Just for the record, a fuse is for over current protection of a device or circuit, it won't control or regulate a system.


Stuart