Spot welder

**darkoford** · May 7, 2022, 05:21 PM

**darkoford** · May 8, 2022, 05:57 PM

Is something wrong with this post?

**Frank S** · May 8, 2022, 10:20 PM

I don't see anything wrong with it. I like the fact you used a much larger transformer to make your spot welder. The ones made with even a large microwave transformer are dismal in power. I even made one several years ago to determine if everyone's claims of the high amperage output was anywhere near real. It takes a lot of core weight to create a large enough magnetic field to achieve enough amps to do any good.

**bruce.desertrat** · May 9, 2022, 05:26 PM

Looking forward to the rest of the build!

**darkoford** · May 9, 2022, 06:28 PM

Originally Posted by bruce.desertrat

Looking forward to the rest of the build!

I can't regulate the current so I have to make an Arduino time limit in milliseconds. The plan is to make a double pulse for thinner sheets.
I use the box from a faulty China inverter (Boxer) welder. I also use a welder inverter fan for cooling.

**darkoford** · May 9, 2022, 06:33 PM

Originally Posted by Frank S

I don't see anything wrong with it. I like the fact you used a much larger transformer to make your spot welder. The ones made with even a large microwave transformer are dismal in power. I even made one several years ago to determine if everyone's claims of the high amperage output was anywhere near real. It takes a lot of core weight to create a large enough magnetic field to achieve enough amps to do any good.

That the transformer must be far larger than the transformer of the microwave oven. Microwave transformer is good only for thin sheets or use several pieces of the same transformers.

**Frank S** · May 9, 2022, 06:51 PM

Darkford if you could get your hands on one of these you could regulate the output by moving part of the core in and out of the magnetic field area
These are wleging machine transformers so obviously the secondaries have more turns than a spot welder and would have to be rewound for the higher amperages at lower voltages

Current can also be controlled by winding the secondary winding with multiple smaller conductors. 2,4,6,8 in hand windings each winding still having the same number of turns, connected in parallel, to keep the output voltages in a similar range