Thread: Spot Welder

Cut off the secondary, and wind on ten turns of wire (any gauge). Measure the voltage on your new secondary, and then divide by ten. This gives you 'volts per turn'.

So if you get 6v, then volts per turn is 0.6v, to get your 4v you divide 4v by 0.6v, which gives you 6.6 turns, so that's either six or seven.

Have you got the welder and looked at the transformer yet?

Many of the those old CIG models were wound in aluminium .
The windings where in the form of flat aluminum in the order of like 30 something wide. They don't look like they would be easy to rewind.

If it is aluminum I would have reservations about the current density available.

Grahame

Thanks Dropcat,
I will try your suggestion and probably use 6mm multi stranded cable and measure the output. The primary has two tappings at 2.3% and 3.2%, I will see how they change voltage and current on output.

Grahame,
Thanks for your reply, The secondary windings are indead aluminium and are easy to remove, so will do what Dropcat has suggested.

I will post my findings as if it works it may be helpful to any others who are looking at doing what I am attempting.

I have allways found your postings interesting and helpful Grahame.

Regards,
Keith.

You might also want to look at using the transformer from an old microwave oven, the older & bigger the better.

These typically weigh in at around 5kg, and are rated at 600-1000 watts.

The secondaries are a bit of work to remove, but it's not rocket science. I used a couple to make high power transformers for amplifiers. You can also parallel them to get more power.

I found a very old one once, no electronics, the timer was mechanical, and its transformer weighs 9kg. A true beast! I've earmarked it for a spot welder.

There are a couple of places on the 'net that run thru this method.