Rawlplug welder

[eddie49]

When used on car batteries ( DC ), the polarity does matter. I would guess since the Rawlplug uses a thin arc welding electrode, that should be Negative, and the workpiece ( often wrongly called "Earth" ) should be Positive. This is also known as "DCEN" or "Straight Polarity". However, the output of a simple transformer Arc welder is AC, so polarity does not apply.

That Chint control transformer is only 150VA. Roughly, 1 VA is 1 Watt, so it is 150 Watts. At 50 volts and 100 Amps, an Arc welder needs 5,000 Watts - that is why they are so heavy! A local s/h purchase, online or at a car boot sale, is the most cost-effective way of getting hold of one.

 

[Stevel]

When used on car batteries ( DC ), the polarity does matter. I would guess since the Rawlplug uses a thin arc welding electrode, that should be Negative, and the workpiece ( often wrongly called "Earth" ) should be Positive. This is also known as "DCEN" or "Straight Polarity". However, the output of a simple transformer Arc welder is AC, so polarity does not apply.

That Chint control transformer is only 150VA. Roughly, 1 VA is 1 Watt, so it is 150 Watts. At 50 volts and 100 Amps, an Arc welder needs 5,000 Watts - that is why they are so heavy! A local s/h purchase, online or at a car boot sale, is the most cost-effective way of getting hold of one.

Thanks so if I bought a 100 amp transformer would that do, but aren't they transformers that transform 240 to 110v, sorry to be a pain

 

[eddie49]

As you said, it is possible to buy a 230v AC transformer rated at 5kVA, but they are called "site transformers", and yes, the output would be 110 volts. What you need is an Arc Welder transformer, such as this one:

Pardon our interruption...

or anything similar that is closer to you.
Arc welder transformers are a special version of transformer, made to provide Constant Current, and that is adjustable - usually with a dial or slider. Say you had an Arc welder capable of 140 Amps, you would probably set it about 1/4 or 1/3 of the way up to test with the Rawlplug.

 

[dave h 2]

What transformer can you buy?
One called a welder, nothing else will survive a dead short through a welding rod.
As previously said old stick welders have no electronics, just a mechanical means of altering the current output and live for ever.
You connect your Kelarc to the torch connection.

 

[Stevel]

As you said, it is possible to buy a 230v AC transformer rated at 5kVA, but they are called "site transformers", and yes, the output would be 110 volts. What you need is an Arc Welder transformer, such as this one:

Pardon our interruption...

or anything similar that is closer to you.
Arc welder transformers are a special version of transformer, made to provide Constant Current, and that is adjustable - usually with a dial or slider. Say you had an Arc welder capable of 140 Amps, you would probably set it about 1/4 or 1/3 of the way up to test with the Rawlplug.

Thanks so if I get an old arc welder is it a matter of just connecting the positive of the rawlplug welder to the positive of the arc welder and negative of the ark welder to the work piece

 

[eddie49]

Thanks so if I get an old arc welder is it a matter of just connecting the positive of the rawlplug welder to the positive of the arc welder and negative of the ark welder to the work piece

No, a simple transformer Arc welder has no rectifier, the low-voltage high-current output is AC. Polarity of the output terminals switches backwards and forwards 100 times per second ( 50 Hz ), so there is no "Positive" or "Negative", it's just AC. Connect the Rawlplug either way.

 

[Stevel]

No, a simple transformer Arc welder has no rectifier, the low-voltage high-current output is AC. Polarity of the output terminals switches backwards and forwards 100 times per second ( 50 Hz ), so there is no "Positive" or "Negative", it's just AC. Connect the Rawlplug either way.

So it doesn't matter that the old rawlplug welders mate runs off DC, just connect them either way round ?
Thanks
Sorry for the questions

 

[eddie49]

Although it starts with 12v DC car batteries as a power source, the Rawlplug instructions do offer advice about how to use the attachment with a transformer, and they make no mention of it having to have a rectifier. At that time, and even now, most transformer-based Arc welders had a simple AC output. So the welding attachment will work just as well ( ?? ) off AC as with DC.

 

[Stevel]

Although it starts with 12v DC car batteries as a power source, the Rawlplug instructions do offer advice about how to use the attachment with a transformer, and they make no mention of it having to have a rectifier. At that time, and even now, most transformer-based Arc welders had a simple AC output. So the welding attachment will work just as well ( ?? ) off AC as with DC.

Thankyou Eddie