AC arc stability

AndersK · Mon Apr 20, 2015 12:31 pm

Coldman wrote:That looks identical to a machine I had here in oz called a cigweld weldskill 200acdc a couple of years ago. It had a weird arc and I could not wait to get rid of it.

Copied this from the Rouges thread.

Were your issues low amp AC?

Im struggeling with mine to get a good arc butt welding 1,5 mm aluminum.
No issues at DC on steel. It runs smooth so if there is something wrong its behind the torch.

When starting at 10 amps DC there is a surge of 35-45 amps before it settles.

Even at 15% EP a 1/16 2% lanthanated balls badly. Now at 3/32 Arctime which is ok but difficult to get the arc where it should be. Running at max 100 amps woth pedal but probably not over 80.
Tried freq 60 to 200

Im not sure what to expect from this machine (Parweld Xti 202 AC/DC)
but other machines I have used has been a lot easier.

What settings do you guys use for this type of welding?

Coldman · Mon Apr 20, 2015 3:32 pm

The issues I had happened across the full amp range and didn't resolve with another torch fitted (ck). A bit hard to describe what went on because I am not a technical inverter expert. Its not that the arc was not necessarily smooth, it was weird in a way that affected the quality of my welds. I got the dynasty 200dx in side by side. Same coupon and prep, one weld beautiful and one weld crap. I had it checked out by an authorised repairer who tested it and could find no faults. That's when the weldskill unit moved out.

Coldman · Mon Apr 20, 2015 3:33 pm

Also the same issue on ac and dc.

dirtmidget33 · Mon Apr 20, 2015 3:38 pm

You said there was a surge of amps. Does this have a hot start feature if so turn it down to zero and try it running it there. Hot start gives extra amps on start up If welding at low amps you don't want to use it.

AndersK · Mon Apr 20, 2015 3:51 pm

Thanks, quite the opposite then

I'd like to hear from others what settings you would run on to see if I can dial it in.

Hot start, I dont think I have that in tig mode
I can adjust hot start and arc force in stick mode.

When pedal is connected I can only adjust pre- and post flow, balance and AC-freq on the front panel.

Pulse is disabled with pedal connected, is that so on high-end machines?

GreinTime · Mon Apr 20, 2015 4:20 pm

AndersK,

On my Everlast PowerTIG250EX the pulse works whether on remote or not. I find it weird that that won't pulse with the foot pedal connected.

Are you sure it's not the 4T settings that are disabled rather than pulse? I'm driving and don't really want to read a user manual while doing so. I'm in traffic right now at a light so it's no big deal, but hopefully it turns green some time today lol.

dirtmidget33 · Mon Apr 20, 2015 4:28 pm

You should be able to use pulse with pedal. I haven't seen a machine yet that had a pulse you couldn't use with pedal.

Downloaded your manual just got to flip threw it quick didn't have much time to read thoroughly but hot start on yours is called initial current it is a % setting. Should be next setting after preflow setting when you scroll threw settings.

dirtmidget33 · Mon Apr 20, 2015 4:42 pm

GreinTime wrote: I'm in traffic right now at a light so it's no big deal, but hopefully it turns green some time today lol.

Get you eyes

out of phone and on the road

tsk tsk tsk

Mon Apr 20, 2015 7:42 pm

AndersK wrote: Even at 15% EP a 1/16 2% lanthanated balls badly...

I run as far EN as the metal will allow, as I can get more heat in the weld for the size of the tungsten.

Consider going to 2,3mm (3/32") tungsten.

Steve S

AndersK · Tue Apr 21, 2015 2:32 am

dirtmidget33 wrote:You should be able to use pulse with pedal. I haven't seen a machine yet that had a pulse you couldn't use with pedal.

Downloaded your manual just got to flip threw it quick didn't have much time to read thoroughly but hot start on yours is called initial current it is a % setting. Should be next setting after preflow setting when you scroll threw settings.

The initial current is available in 4T only, already tried to set it at 5 amps then switch back to 2T

Sam, both 4T and pulse is disabled with the pedal connected.
4T has no use when using the pedal but pulse shouldnt be disabled, cant see any reason why it should. Base current is just a percentage of peak so it should follow the pedal.

Steve, I already changed to 3/32 Arctime tungsten (local LWS didnt have 2% lanthanated in 3/32, just 1/16) but I struggle to get the arc at the end of it instead of jumping around.

Good that you confirmed pulse with pedal on other machines.

I'll open it up to look for anything loose or suspicious, then a call to the service shop.
Been in contact with Parweld but they didnit offer much for help.

AndersK · Mon Feb 22, 2016 1:46 pm

Finally I found my problem.
Machine starts with a looong DCEP pulse which will ball a 1/16 electrode in just a few starts. Even a 3/32 melts off but not as bad.

This is one start with was a fresh 1/16 tapered with a flat point. The black spots are tungsten spatter

: IMG_20160220_51861.jpg (32.54 KiB) Viewed 647 times

After 5 starts

: IMG_20160220_33511.jpg (25.18 KiB) Viewed 647 times

Through a service shop I was told there is a switch behind the panel that could disable the DC start.

Pic speaks for itself, what an improvement that was.

: IMG_20160220_15538.jpg (28.12 KiB) Viewed 647 times

: IMG_20160222_25278.jpg (31.57 KiB) Viewed 647 times

Pics above was testing at 30 amps.
I have then tested with an almost flat 1/8 at 130 amps, no problem initiating the arc on oxidized aluminum.
Not affecting DC start either.

Pulse with pedal self-healed long before I tried this. Probably myself to blame for not pressing the button hard enough