Buzz box output voltage?

You're ignoring losses, of course.

I ran my Miller Thunderbolt off my mom's dryer outlet (30A) for quite a few years, and it never popped once. But 9A? That's pretty questionable.

GWE

Arc voltage runs around 25 volts (open circuit is or should be much higher) so 100 amps would be 2500 watts. You can't really look at the voltage ratio, there are some efficiency losses as well as some ugly phase angles involved in both generator and welder.

Your generator sounds like it is a 4kw to 5kw unit. This is usually enough to run a buzz box at around 100 amps or so. I have a 225 amp Airco shunt style buzz box, I've run 1/8" rod at 100 amps on it. I'll admit that the welder is not a good match for the generator, it loads it up pretty heavily.

Bruce wrote:

I don't know about a Lincoln Tomestone, but most buzz box welders have an open circuit voltage of about 70 volts on the lowest range, and maybe a OCV of 50 on the high range. Buzz boxes are a constant current supply, so the voltage when using it is whatever it takes to maintain the arc. It will vary somewhat depending on how far the end of the rod is from the work and on the rod itself. Different fluxes will make a difference. But your 24 volts is about right for the arc voltage. But your calculation of the primary current is off because the current and voltage are not in phase.

I made some measurements on my buzz box. It draws 6.2 amps when it is on but not being used with about a 70 degree power factor. So my best guess on your welder is that when set to 90 amps and being used, your welder would draw about 12.6 amps. Sqrt of ( 5.75^2 + (9+2.25 )^2 ). That is pure guess, as I have never measured the current drawn while welding.

Dan

Bruce wrote:

Thanks for the answers. I guess it's a little more complicated than basic circuit calculations. I'll pull the cover off the panel and see if I can get an amp hook on my 50A circuit and have some one measure it while I weld something. I'd like to be able to make the welder more mobile but not if I'm going to strain the generator too much.

Keep an eye on your local want ad paper/website - engine-driven welders show up fairly regularly, often at pretty decent prices if not too new and shiny.

I'll do that. It will be a few days before I have a helper I can trust to have their hands inside an open panel.

Yeah, I'd love a nice 10K generator/welder. It's hard to justify the cost though since I can do about all I want with the buzz box.

Hi everyone

Regarding welding arc voltage, I recently measured that using a voltmeter between the clamp and the workpiece, for SMA welding. This is on DC, whereas a buzz-box is always AC, but the mean voltage will surely be about the same (?).

Here are the measurements - all for 2.5mm diameter (3/32nd inch) rods:

"normal" - "basic" and "rutile"

+-------------------------------------------------------+ |7018 |Bohler EV50 |22V |72A| |---------+---------------------------------+-------+---| |6013 "R" |straight rutile |25V |62A| |---------+---------------------------------+-------+---| |6013 "RC"|Zodian Universal rutile-cellulose|21V |76A| |---------+---------------------------------+-------+---|

"cellulosic"

+---------+---------------------------------+-------+---+ |6010 |Foxcel |30V |62A| |---------+---------------------------------+-------+---| |6011 |Arcos Nu5 |20V-25V|62A| +-------------------------------------------------------+

Buzz-box - you'll be using 6013 and 6011 as run sweetly on AC, so looks like 20V to 25V.

Richard Smith

Well, my results have me a little puzzled. Open circuit we measured a 4 amp draw which I thought was odd. Then using 1/8 6011 we measured about

40 amps with the welder set on 90 and about 54 amps gouging at 225. I dropped it down to 60 amps and ran some 3/32 6011 and we were getting around 28 amps. I'm really very surprised at these readings. I suspect this old amp hook meter is reading a little high but even if it's reading 10 amps over I wouldn't try to run this on my little generator. As a test we checked the welding lead and with the welder on 90 we were reading around 100 amps. So the meter can't be totally bonkers.

All I know is my generator is too important to me to test this out and see how well the breaker works.

For those of you who have run off 30 amp dryer circuits, did you ever gouge at 225 like that?

The 4 amp draw open circuit does not seem odd to me. As I said I measured 6.2 amps on my welder. The transformer draws current that is out of phase with the voltage and then there is the fan ( at least on my welder ). I added some power factor capacitors and dropped the open circuit current down to 3 amps. I could have added more capacitors and dropped it down to about 2.3 amps but it would have required fifty percent more capacitors for very little gain.

I don't have anyone to read a meter while I weld, so can't check on the current drawn while welding. But it looks like the arc is a lot more of an inductive load than I thought.

Dan

Think of the circuit.

The welders secondary circuit is a coil. A large one. It feeds two long lines that are called for by a welder to move about - these are inductive by nature. The stick or stinger - simply completes a circuit and you have an inductive loop.

The current flowing in the transformer when there isn't a current (or large one) flowing in the secondary indicates loss in the transformer. This is a designed in loss

- one that makes excuses for you when you stick a stick to the work then the transformer takes the hit - by making some noise some times - as the current increases in the secondary. The loose coupling allows this short to not blow up the transformer or not to break the breaker. The demand surges are lighter as well.

You don't want a tight coupled transformer as the work short could then melt the secondary.

Martin

Mart> Bruce wrote: