The Stovebolt Site Forums The Shop Area The Electrical Bay 1 wire to 3 wire alternator

ok all you stovebolt experts!! here is my question: been running a 1 wire alternator for 5 years no problem. from "batt" terminal a wire goes into ammeter and out to ignition switch (if I remember correctly). I went ahead and stuck a "DA" plug on same alternator with red wire jumped to "batt" term.....where exactly does white wire go??? this is where DA plug stand for dumb[censored]!! I hooked it to pos side of coil and tried ignition switch...both times engine stayed running. not hooking it up to anything things shut off. is it neccesary to hook up white wire at all??

also....what's a good basic dumb[censored] proof wiring diagram so I can clean up the spaghetti under dash??

thanks for all the help over the years!!

This ought to get you where you need to go:
Click Here

Putting a diode in-line on the #1 wire will keep voltage flowing in only one direction (towards the alternator) and insures against engine "run-on" -- you can buy a 4-pack of diodes from Radio Shack for only $3 or $4: Part #1N4001

jo's54,

I guess I don't understand your post. I read that you have a one wire alternator which has worked fine. Now you have utilized the connector in the back and the truck won't shut off.

My definition of a single wire alternator is one that uses the large BATT wire both for charging and voltage sensing...it doesn't use the DA plug, if it even has it.

A two wire alternator has the BATT wire for output, plus the DA plug to charge the field and sense voltage.

Aren't these two different animals..what don't I understand. :confused:

Stuart

Now, my experience with alternators is unplugging the little plug, yanking it, putting a new one in, and plugging the little plug back in.

I have vastly more experience wiring up generators, but since a generator with a voltage regulator is a similar animal to a one wire internally rectified alternator, here's my advice.

Figure out what unit you're using. A one wire alternator means ONE WIRE hooks to it. That single wire should hook into the ammeter.

As Stuart said, this sounds like a two wire alternator. I cannot help you with that, as it is a completely different animal and I don't know how it does what it does. My guess would be that the BATT wire goes to the ammeter, and the other one... your guess is as good as mine. I wish you luck, though.

You can find wiring diagrams for just about anything here

The Topic reads 1-wire to 3-wire so I assumed you swapped out your 1-wire and have put a 3-wire in.

The BATT wire and the #2 wire both go to power ... but using the BATT connection for voltage sensing, as many do (because it's easy to just jump the #2 wire around to the back of the alternator), is not only lazy but a real good way to get a totally inaccurate reading for the built-in regulator!

What you'll see in my image-link (see my above post) is the BATT connection (charge) and the #2 wire (regulator/voltage sensor) are both connected to a terminal block on my firewall.

I'm getting a full 14 volts from the battery to my terminal blocks and feeding all my major components from there ... therefore, the #2 wire is sending a very honest reading of how much voltage those major components are getting and the regulator is doing an excellent job because of that.

The #1 wire simply goes to the ignition.

Sorry, Alan.

That's what I get for doing this late at night.

Alan,

You have to cut us dummies from California some slack..."what me read the topic"!


Stuart

ok.....now I'm really confused!! Alan, you state the #1 wire "simply goes to the ignition"...my ignition switch has 1 hot term and 3 others. which term would you suggest?? thanks

jo's54,


That particular wire must be energized when the truck is running for the alternator to output. If you can identify a SWITCHED terminal that is "hot" only when the key is ON, your home free. Remember, if this terminal is common with the coil in anyway, you must use the diode, or the alternator will backfeed and keep the truck running, even when the key is switch off. This was your original complaint I think!

Stuart

Stuart -- LOL


Jo's54 -- What Stuart said.

Well, guys. I know I've learned something.

Thanks!

[img]http://www.rowand.net/Shop/Tech/images/AlternatorWiringOverview-1974to1985Buick_small.jpg[/img]

Sometimes they'll start charging without the resistor. If you need both, put the resistor in parallel with the light and use a single switched terminal on the ign. switch. If you don't want the light, just use the resistor alone. 10 OHM, 10 Watt
Unless you have an aftermarket "one-wire" alternator with internal sensing, it probably never charged without first revving the engine up. If it is just a standard across the counter internal-regulated alternator, then connecting the #1 & #2 connectings will wire it the way GM intended it to be wired.

Alan,

Thanks for posting that drawing. I just got 3 wire for my '66 but wasn't sure how to wire it up. I stopped at NAPA on Friday and bought the connector for the alternator and then stopped at Radio Shack and bought the diode. Yesterday I soldered up a wiring harness according to your drawing, hooked it up and it works great.

Thanks!
Steve

Your very welcome, Steve!

That wiring setup I illustrate makes a huge difference in delivering power to everything, too.

hey everybody!! THANK YOU!!! turns out my alt. was fine as a 1 wire but the guy at Schuck's who tested it said "it was impossible. there ain't no such thing...." even tho it's been running that way for 5 years.....now I have a better understanding of this "simple stuff".

jo's54,

For the benefit of the dummy from California, could you clarify what you said. I have studied the post and am not sure what happened..whatever it was, you seem happy, so I'm happy for you.

Stuart

i agree w/ atomarc
what happened joe? your one wire is?
Hey rich, what are you running w/ your 292 GMC?

I did a lot of research on this as well and got very confused.
My brother in law convinced me to wire it up with one wire. So despite what everybody else said I tried it and the whole system is running and charging with a steady 14.23 volts at the battery. And my ammeter is showing the correct output as well.

I'm still undecided as to whether or not I will keep it like this.

Billybolt,

The three wire - one wire deal is a personal preference. When all is said and done they will work equally well. If you try to calculate the speed of electricity in a circuit, you get into an area where no mortal belongs.

I think the interesting thing is that a single wire unit can be run as a three wire at the owners discretion. (I hope) I sure hope Mr. Mad Electrical doesn't spot this post...I'll be up a creek without a field winding.

Stuart

Yea atomarc,
This 1-3 wire thing probably has taken up lots of prime real-estate in my brain and removed a year or 2 from my life span.
I had all sources telling me to run 2 or 3 wiers and on the other hand I had my brother in law (who I trust) simply telling me to use one wire.

Throw in a resistor and a push button starter to the whole mix!

As Merle once said "One day we'll look back and say, It was fun"

Holy crap, this is quite a string!! Will be getting into the same thing as soon as the new wire harness gets here.
I think I learned something#@&*
Jim