One wire alternators

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Mrblanche
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One wire alternators

Postby Mrblanche » Sun Nov 11, 2018 9:11 pm

In reading through ALL the posts, I have already come across a number of posts on the subject of a 1-wire alternator. These are popular in hotrodding, but there are two points that are not always mentioned and, rather than add on (and revive) a bunch of old threads, I'll mention them right here.

1. Most one-wire alternators need to come up to a certain RPM level before they will start charging. If your brand-new shiny 1-wire isn't charging, that COULD be the problem.

2. One-wire alternators depend on grounding through their mounting to have a correct "reference" voltage. A bad ground could result in no charging, or excessive charging. If you've seen internet posts on how to make a stick welder with a car alternator, you know that an alternator can put out WAY too much voltage and amperage, under the right (wrong) circumstances. We always advise new hot rod builders to run a ground wire from the alternator to the frame to have the correct ground voltage reference.

I hope one of those will help someone.

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Re: One wire alternators

Postby rockfarmer » Fri Feb 08, 2019 8:31 pm

I think both will help me...hooking up a shiny new 1 wire alternator using Mag and external coil and want to get it right. Keyed ignition. I plan to run a ground from the alternator to the frame. Any recommendations on where exactly to ground to, or pictures?

Also, will the negative post on the coil connect to the side post of the mag?

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Re: One wire alternators

Postby Eugene » Fri Feb 08, 2019 8:39 pm

rockfarmer wrote:I think both will help me...hooking up a shiny new 1 wire alternator using Mag and external coil and want to get it right. I plan to run a ground from the alternator to the frame. Any recommendations on where exactly to ground to, or pictures?
The alternator will ground to the engine block through it's mounting bracket or the belt tensioning bracket. No need to run a separate ground.
Also, will the negative post on the coil connect to the side post of the mag?
Yes. You need to disconnect the magneto's coil and have a ballast resistor on your 6 volt coil or purchase a 12 volt coil with resistor.
I have an excuse. CRS.

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Re: One wire alternators

Postby tst » Fri Feb 08, 2019 9:28 pm

If you use the napa RAY 2134011SW it is designed with a low kick in rpm, it is a delco 10 type, has a boss to put an external ground on, you cannot have to many grounds, they do not hurt, many have bad grounds through the mounting brackets due too much paint and corrosion

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Re: One wire alternators

Postby rockfarmer » Sat Feb 09, 2019 2:01 pm

Thanks Eugene and Tim!

Too late for the alternator recommendation on this one, but I will remember if/when purchasing the next one.

Does the below wiring look correct? In particular the green wire. Since the ignition is a 3 way switch does it need power from the BATTERY side of ammeter, or does it get power from the alternator side when switched to accessory?

48 new wiring for alternator.jpg


The long black and white wire (+ coil) and short black and white wire (light switch) are hooked to ignition accessory post and alternator side of ammeter.

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Re: One wire alternators

Postby rockfarmer » Sun Feb 10, 2019 2:49 pm

wiring 1 wire alt.jpg


Based on the above wiring diagram, there is no need for the green wire in my previous post.

Can I use the 3 position ignition switch, currently installed, as a two position switch ignoring the BAT terminal on the ignition, like below, and use the ACC position as the ON position?

48 alternator preliminary wiring 2.jpg


Or should I invest another $40 for a good push pull ignition?

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Re: One wire alternators

Postby Mrblanche » Sun Feb 10, 2019 9:58 pm

Eugene wrote:The alternator will ground to the engine block through it's mounting bracket or the belt tensioning bracket. No need to run a separate ground.


I have seen several T bucket electrical systems end up a puddle of molten plastic, copper, and aluminum following that advice. Unless you have just assembled your tractor with new, unpainted parts, you may NOT get enough grounding through the mounting brackets. An extra ground wire from the alternator to at least a major connection on the engine will never hurt. Personally, I usually run one all the way back to the battery, or to the ground on the starter (where, by the way, I always run a large ground wire, at least 10 gauge, from one of the mounting bolts to the battery). But hey, you know what they say about opinions and free advice.

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Re: One wire alternators

Postby Eugene » Sun Feb 10, 2019 11:20 pm

Mrblanche wrote:I have seen several T bucket electrical systems end up a puddle of molten plastic, copper, and aluminum following that advice. But hey, you know what they say about opinions and free advice.
Yes, and everything someone states on the internet is true.

Must have been one heck of a fire; plastic 540F, aluminum 1221F, copper 1984F, to create a puddle.

If you don't think you may not have enough grounding between the alternator and engine block, ohm the alternator to engine block.
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Re: One wire alternators

Postby coppersmythe » Mon Feb 11, 2019 7:06 am

good morning from the deep south . i've been using the delco that tst recommended in the post above . works great and starts charging almost at idle for me . i did not put a ground wire on it and its been working fine , but might go ahead and do it , cheap insurance :!: coppersmythe...................
Last edited by coppersmythe on Mon Feb 11, 2019 3:59 pm, edited 1 time in total.

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rockfarmer
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Re: One wire alternators

Postby rockfarmer » Mon Feb 11, 2019 1:03 pm

Took my dog to the tractor and dog supply store this morning. Bought this for $13 and hope it answers my questions above.
2 way ignition tsc.jpg

48 2 way ignition wiring.jpg

Look right?

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Re: One wire alternators

Postby MilGunsmith » Mon Feb 11, 2019 1:18 pm

Does anyone make a 6 volt version? My 8n generator is not charging.

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Re: One wire alternators

Postby coppersmythe » Mon Feb 11, 2019 4:09 pm

good afternoon rockfarmer , i hope i didnt inadvertently hijack your thread . i have had pretty good luck with aftermarket switchs like the one you have , rarely have i "fried" anything . but , my eyes glaze over somewhat with electrical problems . i've succumbed to the siren song of the 12v conversion . although my '48 is "stock". your due diligence tracking down the correct schematic will lessen the need for a fire extinguisher . coppersmythe...............


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