Lincoln v205t curiosity or omen?

[hotrodder]

One for those that understand the witchcraft behind inverters...

Machine's working OK but started behaving differently to normal on AC. Sweet spot for AC balance has always been in the high 60's- mid 70's %EN. Knocking up a tank last week and it just seemed different... can't really describe it, want to say slightly erractic arc (particually starts) but we're talking very slight. Thing that stood out was the size of the etched zone, much wider than usual but tungsten behaved pretty much as expected for the settings used- typical balance settings to get an etched zone of similar size would normally result in a more rounded tip.

Had a little play today, 16swg 1050 Al, 75A FWIW frequency and balance settings on the coupons...



Until now setting the AC balance to 80+ %EN would result in a sluggish pool with bits in it, especially so if (like these coupons) the ally hasn't been touched- just pulled a piece out of the offcut bin and had at it



Normal balance setttings result in an huge etched zone more like i'd expect with low to mid 60s % EN. It's almost as if the calibration has moved from the appearance of the etched zone and puddle behaviour but tungsten behaves as normal for the settings dialed in...

 

[Rick]

I found the same as you, using a Lorch T220.

100hz.

I started out with 70% and found the etched zone really big.

Didn't go any further than this should have tried 90% really.

 

[hotrodder]

Yeah, normal for the etched zone to change size with balance settings (base metal cleanliness has an effect to) but it's the way my machine is behaving that's confusing me...

Until the other day i would get results like in your pic i.e. run a series of beads stepping up the EN balance in 5% steps would produce small differences in pool cleanliness and the etched zone would gradually narrow. Once into the 80s %EN the pool would be dirty and sluggish

Now at 80-85% EN it's welding cleanly and barely a trace of an etched zone. Drop the balance into the 70s% EN and the etched zone goes mad without an increase in tungsten heating or pool cleanliness. Still usable but the arc quality isn't as nice (can't put my finger on it) and while the arc isn't wandering it's less stable at these settings than it was

If it remains like this then not a problem (just be using different balnce settings than before) but i'm wondering if it's a symptom of something going/about to go wrong

 

[RapidResponse]

What i am seeing from your pictures is what i would expect. Please bear in mind that you are using increased AC frequency. If you drop your frquency to 50 cycles it will be closer to the "old days". Another factor that will effect the weld cleaning to penetration ratio will be the shape of the waveform in cathode and anode. You have 3 wave forms on your machine. Put it into square wave on both positive and negative. You will get cleaner results if you use a sinus wave in the negative cycle. Only increase the frequency if the weld is too wide.

 

[hotrodder]

It's in squarewave, can't have a mixed waveform- square, sine or triangularish. Obviously not explaining it properly, the effects of AC balance settings have recently changed. Will do a factory reset in the start up menu tomorrow and find the time to have another play with different parameters

I understand that AC frequency, waveform and even base metal cleanliness have an effect on both the ideal balance setting and the weld (pool cleanliness, weld size and etched zone).

I've had this machine for years, intimately know the effects of small changes to different parameters but recently the effects of AC balance have changed, sweet spot has always been 68-74% EN (depending on the other factors mentioned). As per my previous posts it no longer is, it's as though the calibration has moved but there's something else different about the arc too that i can't quite put my finger on. Running in the 78-85% EN range it behaves how it used to in the 68-74% range (with regards to weld pool behaviour) almost as though calibration has moved. However if it is a calibration issue then i would have expected the tungsten tip to round off more than it used to in the 68-74% range. Tungsten tip behaves as you'd expect with changes to balance, frequency and amperage. Weld pool doesn't

Just wondered if any of the members that understand the witchcraft that powers these things had ever seen anything similar before i speak to a repair centre

 

[Rick]

It's in squarewave, can't have a mixed waveform- square, sine or triangularish. Obviously not explaining it properly, the effects of AC balance settings have recently changed. Will do a factory reset in the start up menu tomorrow and find the time to have another play with different parameters

I understand that AC frequency, waveform and even base metal cleanliness have an effect on both the ideal balance setting and the weld (pool cleanliness, weld size and etched zone).

I've had this machine for years, intimately know the effects of small changes to different parameters but recently the effects of AC balance have changed, sweet spot has always been 68-74% EN (depending on the other factors mentioned). As per my previous posts it no longer is, it's as though the calibration has moved but there's something else different about the arc too that i can't quite put my finger on. Running in the 78-85% EN range it behaves how it used to in the 68-74% range (with regards to weld pool behaviour) almost as though calibration has moved. However if it is a calibration issue then i would have expected the tungsten tip to round off more than it used to in the 68-74% range. Tungsten tip behaves as you'd expect with changes to balance, frequency and amperage. Weld pool doesn't

Just wondered if any of the members that understand the witchcraft that powers these things had ever seen anything similar before i speak to a repair centre

Sorry I think my first post sent everybody off course. I half understood what you was saying. But I thought you was comparing your "new" (which isn't actually new) welder to an old transformer baised machine. This is why I put up comparison pictures of my welder. Which behaves in a similar way to what yours does now. I.e. I'm in the 78-85% range to get a nice weld with reasonable etched zone. Thinking it was a traite of newer welders and there not been a need for as much EP.

In that case its most strange, i'm guessing you've tried another set of tungstens? This could play a part i'd imagine, probably not to the amount we're talking here though. Maybe the Gas also? But again probably not to the amount your talking about.

 

[hotrodder]

First started towards the end of a gas cylinder, continued with a fresh cylinder and in both cases have been welding stainless too which'd show any shielding issues clearly. Nothing's changed with regards to tungsten/tungsten prep and DCEN arc quality is unchanged

Did a factory reset today and had another play. Much better, not done much welding since the reset but appears that arc quality issue has gone when running in the mid 60s %EN. Etched zone/puddle cleanliness relationship still appears a little different to how it used to be...

Top row 60Hz, bottom 100Hz

Never used to able to get a clean pool with EN in the 80s before (unless preweld cleaning was OTT) and i swear there used to be a more noticable difference in the 65-75% range. Could be that i'm imagining it i suppose, either way much better after the reset

 

[Rick]

First started towards the end of a gas cylinder, continued with a fresh cylinder and in both cases have been welding stainless too which'd show any shielding issues clearly. Nothing's changed with regards to tungsten/tungsten prep and DCEN arc quality is unchanged

Did a factory reset today and had another play. Much better, not done much welding since the reset but appears that arc quality issue has gone when running in the mid 60s %EN. Etched zone/puddle cleanliness relationship still appears a little different to how it used to be...

View attachment 14743 Top row 60Hz, bottom 100Hz

Never used to able to get a clean pool with EN in the 80s before (unless preweld cleaning was OTT) and i swear there used to be a more noticable difference in the 65-75% range. Could be that i'm imagining it i suppose, either way much better after the reset

Does look VERY clean, how thick and what grade is the alli? What rods?

Looks much better now.

 

[hotrodder]

Same material as in the first post, 1050-H14 (was 2.0mm today, may have been 1.6mm previously), 2.4mm 1050 wire as i'm almost out of 1.6 at the mo.

Yeah, much nicer to weld with. Can't believe i didn't think to try a reset when the symptoms first appeared . Hopefully it was just a one off glitch.