Rewrap auto motive alternator for single phase power

[Grant-53]

I rewound armatures for my slot cars as a teen. Field strength is a function of the number of turns or loops and the current. Start by using an ohmmeter to measure the resistance in each pole. Larger wire means less resistance but fewer turns. Cooling helps reduce resistance from heat in the wires. Match the field windings to the armature magnetic field strength. Look for old books in the library such as the Audel's series.

[oil pan 4]

I am just going to put the field current on a 24 volt circuit to ram the required current that I need through.

[Stubby79]

Hmm...You'd need to wire in a center-tap on the alt in order to get the welding polarity to switch back and forth, correct?
Or would just using 2 of the 3 phases do the trick? Would that get you a full sine wave or something not quite?

[oil pan 4]

Using 2 of the 3 phases would work from a functional stand point but might not provide enough power to weld aluminum. It takes a lot of amp to weld aluminum. You can only get about 1/2 to 2/3 the power out of an alternator when using 2 of 3 phases depending on if its a delta or wye wound stator.

[Stubby79]

Hmm...might(?) be easier to build a circuit to flip the polarity back and forth a few times a second, between the ground cable and the torch. Or one to rotate through the phases to dissipate the load evenly between all 3 or 6 phases.

It's too bad that you need AC for aluminum, otherwise this would be dead easy...

[oil pan 4]

It only takes less than a second of reverse polarity to melt the tip off the tungsten electrode and burn the copper collet in contact with the tungsten electrode.

I have a stator that I can chop up now.

(the old dirty burnt looking one out of the 2 shown)
Just need to figure out what size magnet wire it is and order some along with the little buffers that go between the copper wire and the steel shell.

But there is a problem. I was assuming these were 6 pole alternators. I am getting 840Hz at full speed. Which means its a 12 pole.
I don't even know if 800+Hz will even work for welding aluminum, because that is double the frequency normally used.
So I need to find out if roughly double the frequency I was expecting will even work or figure out way to convert from 12 pole down to 6 pole.
I know there are 3 phase industrial motors out there that can have their number of poles halved when you wire them in. So you can keep one kind of spare motor on hand and use it for both 2 pole and 4 pole applications.
So it can be done.

[Jared]

If you are still working on this, I hope you are. You might want to stay with a wye winding. Wye wound transformers are able to put out higher amp. Delta wound transformers put out higher voltages.

You might see, with hand spinning the alternator, putting some of the leads in series and parallel what kind of VA you can get. Or some way to keep it spinning at a steady rate.

The wire looks like it is 16 solid.

[WyrTwister]

Just a wild guess . What would it do if you tried welding Al with un filtered DC from a full wave rectified AC ? Half wave ?

God bless
Wyr

PS I have it in my mind it is common for automotive alternators to have 6 diodes . So 6 Poles or 3 poles ?

[oil pan 4]

Aluminum can be welded with reverse polarity DC, but it takes very large and expensive tungsten electrodes, very expensive helium and a large water cooled torch.
That is how they used to tig weld aluminum in the 50s and 60s back before advanced welding inverter technology. They did have motor generator welders for higher frequency 100 to 1000Hz A/C and high frequency arc stabilizes for 60Hz welding, but helium and big tugsten was cheap so none of that really caught on until the 80's or 90's.

Most automotive alternators appear to be 6 or 12 pole.

Wye can only put out more amps than delta if it's a 4 wire wye. Other wise all your hifjer amp rated stuff appears to be delta. For example if you can add a neutral to a 3 wire wye connected transformer those power wires can handle something like 74% more power.
Going 4 wire makes wye a totally different animal.