- Thread starter Bruce May
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The more expensive inverters with adjustable arc force can do celluosics.
http://www.weldequip.com/inverter-fusion-180ma.htm
Most inverters won't.
http://www.weldequip.com/inverter-fusion-180ma.htm
Most inverters won't.
wheresmejumper
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i thought OCV was the factor for running them?
For AC.
For DC inverters, it might be a part of it, but it isn't the whole answer.
e.g. these
http://www.decaweld.com/default.asp?idA=34&idC=20&cmd=searchProd
It's only the top end Mastro range with adjustable arc force that run cellulosics, and they make a thing of it.
My inverter is made by the same people and has a 90V OCV. Not a peep in the manual about running cellulosics. Equipment makers don't normally fail to talk up a feature, so I assume it doesn't.
wheresmejumper
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that inverter fusion says it has automatic arc force on its website,not adjustable?but does quote cellulose capabilities
i tried my welder with bohler fox cel rods,70 OCV with adjustable arc force
it might be my skill thats the problem,but they dont run very well
they are okay vertical down,but any other position you have to keep the rod buried,or literally drag the rod along the piece to keep them lit.as soon as you increase the arc length any bit,e.g.to step forward for whip and pause,it goes out.im guessing this is a voltage issue,not AF.with AF turned up,you could easily use the rods to cut right through the piece.
im going to try them on another inverter next week,with automatic AF,but 105 OCV
fumes are excessive though,5 or 6 rods left me with a fair headache
i tried my welder with bohler fox cel rods,70 OCV with adjustable arc force
it might be my skill thats the problem,but they dont run very well
they are okay vertical down,but any other position you have to keep the rod buried,or literally drag the rod along the piece to keep them lit.as soon as you increase the arc length any bit,e.g.to step forward for whip and pause,it goes out.im guessing this is a voltage issue,not AF.with AF turned up,you could easily use the rods to cut right through the piece.
im going to try them on another inverter next week,with automatic AF,but 105 OCV
fumes are excessive though,5 or 6 rods left me with a fair headache
matt1978
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It's not just the Arc Force its the OCV of the machine that really counts
We do machines that have fixed and variable Arc Force but still not great on CEL rods, if its designed for CEL it will state it somewhere in the sales literature
We do machines that have fixed and variable Arc Force but still not great on CEL rods, if its designed for CEL it will state it somewhere in the sales literature
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The question of why most inverters, even ones with a high OCV, struggle with cellulosic rods has cropped up a few times with never a completely satisfactory answer. So I asked the TWI.
The answer is that you need:
1. A high OCV, over 70V.
High levels of cellulose in the flux just require more volts to ionise and get conducting. The PD across a celluosic arc is higher than across a rutile arc.
2. The welding machine must have a drooping Volt-Amp output characteristic.
Traditional welding machines had this allowing the welder to alter the current by altering the arc length. i.e. they are not true constant current sources. Most inverters are true constant current and the current is independent of arc length. Now the electronics and maybe firmware in an inverter can be adjusted to give a drooping characteristic, hence the celluosic switch on some inverters to alter the personality of the machine.
From the TWI.
"With cellulosic electrodes a drooping characteristic is needed to stabilise arc length. If the arc length increases the current is reduced, burn-off is reduced and hence the arc length shortens. If the arc length reduces, burn-off increases and the arc length lengthens. This characteristic also gives the welder greater control over the arc."
Arc force cuts in when the arc is short and the voltage drop across it is low and winds up the current substantially.
http://www.millerwelds.com/resources/articles/index.php?page=article108.html
Now in the UK and I'd guess most markets, cellulosic electrodes are a minority interest, and makers find true constant current inverters are what people want. If you want the extras to use cellulosics you have to pay for them.
As for the IFL machine which can burn cellulosics but has no switch, it's computer controlled, so I'd guess that when the arc starts it measures the voltage and current of the arc and if it looks like a cellulosic electrode is being used, it sets it's V-I curve appropriately.
The answer is that you need:
1. A high OCV, over 70V.
High levels of cellulose in the flux just require more volts to ionise and get conducting. The PD across a celluosic arc is higher than across a rutile arc.
2. The welding machine must have a drooping Volt-Amp output characteristic.
Traditional welding machines had this allowing the welder to alter the current by altering the arc length. i.e. they are not true constant current sources. Most inverters are true constant current and the current is independent of arc length. Now the electronics and maybe firmware in an inverter can be adjusted to give a drooping characteristic, hence the celluosic switch on some inverters to alter the personality of the machine.
From the TWI.
"With cellulosic electrodes a drooping characteristic is needed to stabilise arc length. If the arc length increases the current is reduced, burn-off is reduced and hence the arc length shortens. If the arc length reduces, burn-off increases and the arc length lengthens. This characteristic also gives the welder greater control over the arc."
Arc force cuts in when the arc is short and the voltage drop across it is low and winds up the current substantially.
http://www.millerwelds.com/resources/articles/index.php?page=article108.html
Now in the UK and I'd guess most markets, cellulosic electrodes are a minority interest, and makers find true constant current inverters are what people want. If you want the extras to use cellulosics you have to pay for them.
As for the IFL machine which can burn cellulosics but has no switch, it's computer controlled, so I'd guess that when the arc starts it measures the voltage and current of the arc and if it looks like a cellulosic electrode is being used, it sets it's V-I curve appropriately.
matt1978
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Good Point Tez, but its simply because later Rules and Regulations have meant that the average OCV of machines has become lower and lower than they used to be, so it wasn't such an issue before.
Same as HF on Tigs
Rrunnach
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Good Point Tez, but its simply because later Rules and Regulations have meant that the average OCV of machines has become lower and lower than they used to be, so it wasn't such an issue before.
Same as HF on Tigs
Ah, ok. Thanks for clearing this up, Matt....
Cheers..........
wheresmejumper
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if anyone wants a couple of 6010 rods to try out before buying a box to see if your plant can burn em,send me a pm and i will send a few for cost of post.
wheresmejumper
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yeah no bother,pm me your address
mybuttssplit
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Cellys are a pretty much obsolete rod along with acid rods etc.... The only half decent application I can think of is for building up material in the very down. Putting a root in is ok stoved although it sounds like your cutting the pipe in half not welding it!
I believe they would have had a place in the old days when 7018s weren't as well developed and as easy to use but nowadays a 7018 or 7016 root is so easy to put in. Their place has been filled.
I believe they would have had a place in the old days when 7018s weren't as well developed and as easy to use but nowadays a 7018 or 7016 root is so easy to put in. Their place has been filled.
No, but they usually had a high OCV range and they naturally had a drooping current characteristic. Inverters typically have a dead constant current no matter what the arc length, apart from when the arc is very short and arc force boosts it. That's why you need an inverter with either a cell setting to move it to a drooping characteristic, or the internal smarts to decide that a cellulosic rod is being used and shift the characteristic itself.
denlow60
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you are very lucky that you are not come to be in tension , because in formes day they had an open voltage of 70V .
this should not be more to this because many people have died .
now they have a safe open voltage of 42V/50V .
modern welding machines ,weld all kinds of electrodes with one open voltage of 50V .
