I've heard this debate for years and years...I ended up splitting right down the middle - I run 2 wires - been working perfectly for just as long (years and years)- no idiot light - no special can't find one in timbuktoo alternator - pretty much the best of both worlds. I may be a tad jaded...
I guess I explained it wrong but what you said about one ground for each THING is what I meant by circuit! I did not mean 2 or more ground wires for each THING! I,m a hobbiest not a pro with a shop,I give advise on what I worked on for myself! If you own a shop and tell me as a customer that a steel body and steel frame is a good enough ground compared to a copper wire I,ll be your x customer. Pete
If they DON'T tell you that, you SHOULD be their ex-customer. Don't be afraid to learn something new.
I've got 3 hotrods that all have electronic ignition (Pertronix on two, and GM HEI on the other) and they all have one wire alternators. All work perfect, and have from 11 yrs. to just a couple years on the three cars. I keep hearing this crap about how one wires don't work, and I keep looking for one of mine to act up.
If steel isn't a good ground then why does Detroit ground everything to the chassis and engine, neither of which are copper? And we always used steel ground rods driven in the ground for 35 years I worked as an electrician. Copper wire to it, but a steel rod.
Ditto, what Squirrel said re; "rev it a bit" to begin charging.... I'm ok with that,...but I can see why car makers wouldn't use 'em....I mean...how do you explain having to do that, to someone who is doing good just to get the doors unlocked.......... Cars have to be "turn-key" for anyone, anywhere, so the mfgrs will stick with the 3 wire until the 1 wire critter can be made to eliminate that "proceedure". 4TTRUK
Beats the shit out of me!! On my house the rod in the ground is copper!! Was in construction for 33 years(retired) all ground and lighting rod grounds on commercial buildings are copper in Pa. I,m not a electrician (carpenter) always told copper was the best,unless you can afford silver,gold, platinum!! Pete
The major difference between the two is that a one wire uses a self exciting regulator. One of the two wires excites the regulator in a 3 wire. A single wire will not charge at idle. You need to rev the engine up to about 1200 roms to get the unit to charge. This isn't too bad in a vehicle that has no accessiories, but if you have any kind of electrical load, they aren't woth squat.
I have both.... idiot light at lower right, voltmeter at right on the instrument panel. The idiot light is in the excitation line (T1), if you don't use an idiot light you should have a resistor (or perhaps a diode, I've heard) in that line. But I use a lamp, which tells me the alternator is working (of course, the voltmeter does that too but is not as noticable when driving).
Car manufacturers ground everything to the chassis and block because it's more economical than returning everything to the negative side of the battery with copper wire. Keep it in perspective. Copper is a more efficient ground in that it will have greater conductance / amperage carrying capacity for a given cross sectional area when compared to steel, but steel works great in a vehicle because the block and frame represent such a large path that it works as good as copper and is more cost effective. Bob
Thanks Bob!! We are all right!! Now lets get out and build something!! (did you see the video on the burnout page) Pete
Well now, lucky you! Why don't you 'splain why GM doesn't use "1 wire" in their cars? Ah yes, I can hear the theme from Jeopardy now!
I've had a one wire on my car for 3 years and never had a problem. I went to it to clean up the wiring-I'm anal-I admit it. Just for grins, I looked up the operation of a one wire from PowerMaster. A one wire alternator has a turn on point (sometimes called cut in, which is typically 1200 engine RPMs). This is the speed where the internal sense circuitry connects the battery to the voltage regulator, thereby turning the alternator on. Once the voltage regulator turns on, the alternator will remain on and charging until the engine comes to a complete stop. If the engine idle speed and pulley ratio combination do not allow the alternator to come up to this point during starting, the engine will have to be revved up to turn the one wire alternator on. The sense circuitry in the one-wire regulator can be bypassed to excite the alternator as soon as the ignition switch is turned on. This is called three-wire operation. This means the alternator will not be dependent on reaching a certain turn on RPM.
I have spent a lot of time looking for a "how to wire " a three wire alt.No two ways the same.One shows terminal one connected to alt. output.terminal 2 to a bulb to ground. I do not have any motor manuals so have no references.
This is an important bit of detail that a lot of people miss. People often think that a one-wire alternator NEVER charges until it spins up to a give RPM. This isn't true. It simply needs to create a sufficient magnetic field to BEGIN charging. So, for those of you using the 1200 RPM number... one blip of the throttle generates the magnetic field, which excites the circuit, and voila... it's charging REGARDLESS of RPM, even if below 1200 again. Also, it's about creating the magnetic field, which does NOT require the engine run at 1200 RPM... that's just some number someone pulled out of a hat. 1) you can get sufficient RPM by changing alternator pulley size, and 2) you can lower the required excitation level with a well-built coil... that is, if the coil is capable of producing sufficient magnetic field to excite the circuit at, say 600 RPM, the complaint goes away entirely. /another 2 cents
I have a one wire 10si in my '51 (sbc). I'm not a fan. I've gotta hit 2-2500rpm for it to start charging. For the longest time I thought the damn thing was faulty. I've wired it in as a 3 wire, but because current takes the path of least resistance it still behaves like the one wire - until I swap out the internal regulator with a regular GM part. EDIT: I just went out and checked, and my idiot light was unplugged. That's why it was working like a 1 wire.
just my .02 - just had to replace my 13 y o one wire no name chrome alternator. $130 and a $20 reward bonus from pep boys and it was on the shelf . doubt they would have had a three wire as we all know most parts stores don't stock what doesn't sell. my one wire runs dual a/c units, dual car stereo amps, and everyother gadget idling in traffic. if the needle on the volt meter dips a little low throw it in nuetral tap the gas slightly and bam were charging. boils down to personal preference
I'd bet they're copper coated steel, not pure copper. I don't think I've ever seen "timbuktoo" used in a HAMB post before, but of course I haven't read EVERY post and didn't use the search function to see if there were more. But it reminded me of a rhyme: As Tim and I a walking went we spied three maidens in a tent as they were three and we but two I buk one, and Timbuktu I have used both one and three wire alternators, and usually use a three wire, because I am not afraid to install them the way they were designed to be used.
I'm thinking of using an old external regulator alternator in the next one. I have one of those neat old Delco finned aluminum electronic voltage regulators from the mid 60s.
Usually the steel-to-steel mounting of the alternator to the engine is good enough, but I once had a problem with the three-wire alternator (on an OT car) charging the battery... I ran a (copper) wire from the alternator housing direct to the battery negative, that fixed it. Of course, I guess I could have tried cleaning the steel mounting surfaces....
One more vote for one wire. Simple to install, no extra wires to scratch your head over at to which one goes where. I have been using one (Speedway Motors at that) for 4 years and no issues.
Good advice. I've only used them on stock cars, I was never comfortable with them on street cars, why mess with a known wiring configuration? Bob
I've also used both. Right now have a one wire on the 55 Chevy wagon but it hasn't been back on the road much to really check it out. It does need revved to first begin charging but seems to put out decent voltage. The part of the reasoning I don't understand is the one wire vrsus three just for looks. Who cares? Three can be run together and hardly noticed. It's an engine. It's supposed to have wires.
We keep several 1 wire 10si's in stock at all times, I wouldnt worry about not being able to find one on the road, if they don't have a one wire than grab a three wire and a piece of primary wire for a jumper to get you by, no issue. Likely unless you bought some bill & ted's exclelent alternator from schucks it will last as long as you will anyhow.
I agree, don't use one wire alternator. Good article in Street Rodder in the past few months saying the same thing. I use a FORD 55 amp alternator on my 292 Y-Block 1955 Thunderbird. I used alternator, regulator and alternator/regulator wiring harness from/for a 1969 Mustang 351 engine with A/C - that way you get a two belt pulley on front so you can turn alt/water pump and have the right alignment from crankshaft to alternator. Run the wire harness between alt and regulator and then wire in power and idiot light at regulator. I have an Auto Meter voltmeter that gives me 13 plus volt reading at all times as required. There's a lot of kits out there for installing a GM alternator on Y-Blocks - not necessary. Best regards. RT
To tell a 1 wire from standard alt take the back off and look at the regulator, it should be marked, usually SE for self exciting if it is 1 wire. The 1 wire was invented by Delco for tractors, bulldozers and such like that had minimal electrical systems to begin with. I prefer the 3 wire but if you prefer the 1 wire they are nearly as good.
Hi guys am new here glad to read you all talk about auto parts and cars in this question you ask about one wire alternator or not but It's set up to run 1 wire but with that plug out you can run it 3 wire. I strongly suggest you run it 3 wire as 1 wire will have charging issues.
The Jalopy Journal
