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Modifying AC Buzzbox?

Posted: Sat Nov 21, 2015 5:33 am
by VincenzioVonHook
In short someone I know is clearing a lot of land (needs 40 acres of pretty dense land cleared) and chewing threw a lot of old attachments which are rusty and worn. Lots of cheap mans hardfacing with 7024 is on the cards, but im too broke too afford a decent 200-250A inverter at the moment. He also has a few buckets that need finishing. All the critical welds have been pulled dualshield in his shed, the rest are to be finished by me.

I'm no 1st class welder, I only have my AS1554 GP certs, but can handle a mig well, and manage with a stick. We are in the middle of nowhere, looking at this AC buzzbox we didn't even know existed (this property is 1600 acres and came with a few sheds worth of tools, 3 flatbed trucks and a tractor). Its some random chinese (jiali?) 250A AC box.......pretty rubbish duty cycle @250A (like 10%), runs 180A @20%, 120A@50%, 80A@80%. It is brand new and has the option of 400v/240v. It has a wicked thick power lead, but with nothing on the end. It needs a 10kv input, which we have here (12.5kv gen).

Here's the Question. It will be ran around 170A with 3.2 7024, and im not sure what to run these 4mm 7014 and 6011 we have here. Will a 15A lead burst into flames at 160A plus? I know nothing about electrical circuits, so have no idea what is needed to power this thing......we have a few 15A lead heads here and were going to wire that up tomorrow morning and have a crack. Am I insane? Im pretty sure it wont see more than 170-180A in general.

Second, there are a huge bunch of heatsinks and large fans here in a box. Would any of that help with the duty cycle? The Fan in the thing looks pretty poxy for a 250A transformer, and there is a fair bit of room inside for a few sinks/ exhaust fans (i will keep it positively pressured though). What i would like to know is whether this would be beneficial, or is most of the heat stored to deep in the windings to be effected by airflow and heatsinking?

Sorry for the length, and stingyness of this post, but if we can get this to run off a 15A lead and have a marginally acceptable duty cycle it might be okay for free. It looks brand new. It has a brand new 300A electrode holder and 300A work lead sitting in a pack on top, so no money lost. Or am I being a cheap c*** and wasting time?

Re: Modifying AC Buzzbox?

Posted: Sat Nov 21, 2015 5:43 am
by VincenzioVonHook
Ha just did a ebay search to see if these things still existed and bam

http://www.ebay.com.au/itm/Jiali-ARC-We ... Swk5FUxxOr

Exactly the same as this but 250A..........just in case anyone wanted to know what this thing was. I had never heard of the brand until i dug this out the shed. Wouldn't buy one, but would take one.....

Re: Modifying AC Buzzbox?

Posted: Sat Nov 21, 2015 7:56 am
by weldin mike 27
If you can get some use out of it as is, good, but its a waste of time mucking around with it, besides pointing a fan at it. There are heaps and heaps of heavy duty welders on ebay. Lots of ex tafe that have done hardly any work. Cigweld Transarc. Tough as nails. http://www.ebay.com.au/itm/CIG-CIGWELD- ... SwwbdWKcmJ

Mick

Re: Modifying AC Buzzbox?

Posted: Sat Nov 21, 2015 8:47 am
by Coldman
The power source should run 160a on a genuine 15a 240v circuit no problem. If you are on 3phase even better. Don't bother messing with fans.

Re: Modifying AC Buzzbox?

Posted: Fri Nov 27, 2015 8:29 pm
by VincenzioVonHook
Coldman wrote:The power source should run 160a on a genuine 15a 240v circuit no problem. If you are on 3phase even better. Don't bother messing with fans.
Ha, at 170A i could only burn four 5/32 6013 rods one after another before it clicked into thermal protection. Got bored, put another fan in the back, and cut out a little vent on top and added another 200mm PC fan for exhaust, as well as a few heatsinks of the transformer. Cost me nothing as the parts were here, and now I can burn seven of the same rod. Why are people so deadset against modifying something if it costs nothing? I'd say it went from a 20ish to 40ish Duty cycle at 170A just from a few free mods. (Still takes five full lifespans of a dog to cool down once it reaches cut out temo though, there is no fixing that.)

Way cheaper than buying another welder (considering I have many back home!) Haven't tried anything above 170A. If anyone is stuck out in the middle of nowhere, and has access to a simple, cheap chinese AC box, they work fine. A bit hard to start, but they work fine. Just rig up some cheap fans and you are good to go. I managed to pull decent welds, they look the same as the welds from my inverter, just saying. You do have to watch arc length though, too short and they extinguish as they have really low ocv (48v)