Hello, I'm a newbie occasional DIY welder using an old 90A stick welder. However, I need to lug it about and, being of advanced years, find the weight a real struggle. Iv'e recently seen ads about inverters and these sound like really light weight stick welders which is what I need. Is this so? And, if so,any info about this and the pros and cons, reliability etc would be very helpful.
- Thread starter roop5
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Inverters are ultra lightweight (typically around 4/5Kilos) due to their all electronic build, ie. no main transformer as with conventional type welders. They also convert AC mains power in to DC power out which results in much smoother output over conventional type transformer machines. They are fantastic bits of kit, however, can be unreliable. The cheapest sets on the market (from the 'box-movers') are throwaway & I wouldn't touch one! There are also more & more direct Far Eastern imports creeping on the market, again, I wouldn't touch one! They are highly complex bits of kit, which you cannot repair yourself, so a reliable after-sales service is essential.
weldequip
weldequip
inverters, info required, please
Thanks for your comments. Can you mention a few makes/models that you would consider as good bets. Do you have any info one their reliability--complex electronics sounds a bit scary! Would a second hand one be too risky? What features do you think are essential?
Thanks for your comments. Can you mention a few makes/models that you would consider as good bets. Do you have any info one their reliability--complex electronics sounds a bit scary! Would a second hand one be too risky? What features do you think are essential?
FORGET a second hand Inverter unless it's a knock-off! or very, very little used! The leading brands such as Murex, Lincoln, Kemppi, Fronius, IFL etc. will all provide a lot less headaches & have reliable after-sales support over the 'box-movers'. You get what you pay for!
weldequip
weldequip
Specialist welding electronics service engineers I employ hate working on the things! They have many different circuit boards fitted so your first problem is diagnostics, yes. And then, most of the components on those circuit boards are 'surface mount', which means they are extremely difficult to replace - you can't simply re-solder a new component on there (if you have found the faulty one) & more often than not it means a replacement board. On quality stuff that can mean up to 70% of the original cost of the machine! & on cheap stuff, it's throw-away.
weldequip
weldequip
Hi Lexi regarding the inverter welder, they are the most simple welding machine type to fix. As technicians and repair specialist we have a few simple techniques to track it down to which pcb board is giving a problem and we simply replace the board which cost wise is peanuts. Since the beautiful inception of these welders its made repair work a breeze on our end. But to be quite frank we hardly get them in for repairs of defect, its 90% of the time a fault that was caused from the courier dropping the welders.
irondarren
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being dropped is one thing inverters, dont lend them selves to very well. Although a lot depends on the design of the inverter and how close the electronic wizardry is to the case and how well it is protected inside
I have a Chinese welder and recently 'fixed' or re-designed mine, I had no information and had to draw out my own schematic diagrams. These machines are complex and have life threatening voltages inside. You don't mess inside unless you are competent and I wouldn't post information that would encourage others to kill themselves!
Mosts imports won't supply any kind of circuit diagram and even the 'agent' would probably ship back to China (long downtime). Some agents won't service them because the worst may not satisfy appliance safety regs, so they can't legally repair, test and return them. After sales service is important, so find out what that means and costs.
Yes, these inverters with AC/DC and HF are complex. Without diagrams, the power side is fairly easy to understand, but all the control side means some quite complicated circuitry. Mine doesn't have a microprocessor - I'm very happy about that.
Now the design: These inverters use semiconductor devices that are continually improving in voltage and current ratings. These (and there could be 16 of the same type) are the first point of common failure. The imports are often rated at 220 volt and whilst they work on 230 or 240, this voltage alone runs the inverter very close to the input semiconductor over voltage limit, when they 'pop'. My welder circuit boards were assembled 2 years ago, the design could be older. The semiconductors in the primary switcher(16) were each rated 15 Amp 550 volt. Now my unit has 21 amp 650 volt devices fitted. International Rectifier are a respected manufacturer of high power MOS devices. I'm not sure when you see a brand name on a Chinese welder (mine were Toshiba) if you can believe its pedigree.
Inverter welders need a mains supply which doesn't have spikes e.g from heavy plant machinery on the same circuit. They don't like running on supplies fed across long distances on thin extension cables either.
Water? My welder has a rear panel connector for the torch water inlet and a short pvc hose running rear to front inside the unit. My hose was loose. ANY water inside a solid state welder is a disaster for faults unless, you have access to complete working circuit boards. I've replace my pvc pipe with rubber and eventually I'll take the water outside with a Dinz adapter.
So, I'm happy with my Chinese inverter, It's now better than they made it and I know how it works and how to fix it at the component level. But if I was electronically ignorant, I'd only go to a brand that had affordable service backup. Personally, I also try to buy a product where I can get a technical service manual. At some future date I may not fix it myself, but if the manufacturer or agent ceases trading, I have a chance to find a man who can fix it.
For anybody on a single phase domestic supply needing to TIG ali to 200 Amp a.c, I don't see any alternative. The duty cycle for any of my transformer machines is worse than my Chinese inverter TIG which could be improved. You can't cool a large transformer core easily, but there are some options with inverter heatsinks.
I notice somebody mentioned surface mount components to which I'd add 'microprocessors'. It is virtually impossible to fix circuit boards like this at component level - the boards are cheap to manufacture but may have big mark ups when sold as spares. However, most faults are likely to be on the 'easier to fix' power side. The advantage I have with my imported welder is they lagged behind on the technology and used discrete parts I can source,improve and replace.
Mosts imports won't supply any kind of circuit diagram and even the 'agent' would probably ship back to China (long downtime). Some agents won't service them because the worst may not satisfy appliance safety regs, so they can't legally repair, test and return them. After sales service is important, so find out what that means and costs.
Yes, these inverters with AC/DC and HF are complex. Without diagrams, the power side is fairly easy to understand, but all the control side means some quite complicated circuitry. Mine doesn't have a microprocessor - I'm very happy about that.
Now the design: These inverters use semiconductor devices that are continually improving in voltage and current ratings. These (and there could be 16 of the same type) are the first point of common failure. The imports are often rated at 220 volt and whilst they work on 230 or 240, this voltage alone runs the inverter very close to the input semiconductor over voltage limit, when they 'pop'. My welder circuit boards were assembled 2 years ago, the design could be older. The semiconductors in the primary switcher(16) were each rated 15 Amp 550 volt. Now my unit has 21 amp 650 volt devices fitted. International Rectifier are a respected manufacturer of high power MOS devices. I'm not sure when you see a brand name on a Chinese welder (mine were Toshiba) if you can believe its pedigree.
Inverter welders need a mains supply which doesn't have spikes e.g from heavy plant machinery on the same circuit. They don't like running on supplies fed across long distances on thin extension cables either.
Water? My welder has a rear panel connector for the torch water inlet and a short pvc hose running rear to front inside the unit. My hose was loose. ANY water inside a solid state welder is a disaster for faults unless, you have access to complete working circuit boards. I've replace my pvc pipe with rubber and eventually I'll take the water outside with a Dinz adapter.
So, I'm happy with my Chinese inverter, It's now better than they made it and I know how it works and how to fix it at the component level. But if I was electronically ignorant, I'd only go to a brand that had affordable service backup. Personally, I also try to buy a product where I can get a technical service manual. At some future date I may not fix it myself, but if the manufacturer or agent ceases trading, I have a chance to find a man who can fix it.
For anybody on a single phase domestic supply needing to TIG ali to 200 Amp a.c, I don't see any alternative. The duty cycle for any of my transformer machines is worse than my Chinese inverter TIG which could be improved. You can't cool a large transformer core easily, but there are some options with inverter heatsinks.
I notice somebody mentioned surface mount components to which I'd add 'microprocessors'. It is virtually impossible to fix circuit boards like this at component level - the boards are cheap to manufacture but may have big mark ups when sold as spares. However, most faults are likely to be on the 'easier to fix' power side. The advantage I have with my imported welder is they lagged behind on the technology and used discrete parts I can source,improve and replace.
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One of the nicest ones i have used was a Messer Greisham, probably the lightest and smallest aswell. Its always kicking about in the back of the van, and must be 7/8 years old now.
Like Weldequip mentioned, if you want a reliable one, go for one of the bigger brands, to ensure spare boards should be available for sometime should you need one.
Migatronic, Esab, Murex, Miller, Kemppi etc.
Like Weldequip mentioned, if you want a reliable one, go for one of the bigger brands, to ensure spare boards should be available for sometime should you need one.
Migatronic, Esab, Murex, Miller, Kemppi etc.
matt1978
www.lorch.eu
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My brand.... Lorch (German made), is also very good, its worth bearing in mind that 2 main things kill these small inverters.
1)Heat
2)Impact.
All of our small inverters 140-220 amps, come with a full 3 Year warranty and are all guaranteed crash proof. By that we mean that they can withstand a fall onto a concrete floor from just under 1 meter (To replicate falling from a bench) They also have side impact resistance. Shock is what kills these small machines because most of them use a Quartz crystal which resonates at a given frequency to switch the inverter, when dropped or knocked, this crystal becomes fractured and switches at a different frequency and eventually causes the inverter to fail.
All of our inverters are digitally controlled which means that the machine will give you the best possible characteristics for any welding situation, are all generator compatible and can be used on very very long extension cables (Primary or Secondary) without causing problems to the welding result.
To show that I am not biased or this is not an advert, Fronius and Kempii units are also good kit.
1)Heat
2)Impact.
All of our small inverters 140-220 amps, come with a full 3 Year warranty and are all guaranteed crash proof. By that we mean that they can withstand a fall onto a concrete floor from just under 1 meter (To replicate falling from a bench) They also have side impact resistance. Shock is what kills these small machines because most of them use a Quartz crystal which resonates at a given frequency to switch the inverter, when dropped or knocked, this crystal becomes fractured and switches at a different frequency and eventually causes the inverter to fail.
All of our inverters are digitally controlled which means that the machine will give you the best possible characteristics for any welding situation, are all generator compatible and can be used on very very long extension cables (Primary or Secondary) without causing problems to the welding result.
To show that I am not biased or this is not an advert, Fronius and Kempii units are also good kit.
zardoz
Old school Socialist
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What about the ebay machines such as the Rehmann TIG200 inverter http://cgi.ebay.co.uk/Rehmann-TIG200-inverter-TIG-MMA-welder-2-years-warranty_W0QQitemZ130168148382QQcmdZViewItem?hash=item130168148382 it states
'Rehmann TIG200 inverter TIG/MMA welder 2 years warranty' went for £205. Are they any good at all ?
and
Another
'Rehmann TIG200 inverter TIG/MMA welder 2 years warranty' went for £205. Are they any good at all ?
irondarren
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zardoz i might be wrong here but i think my old pico 140 is siemens based (i could be wrong), that machine has been bake boiled and fried. and still runs an arc rod down nice as you like.
mishka
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Ahh, just takes a bit of practice and, as always, the right tools. The smallest I've done is 0402 on mobile phone development boards, production goes to 0201 or 01005. I would imagine that heavy gauge stuff you find in welders is 0603 or larger.
(if you don't know what these numbers mean, check out this page)
matt1978
www.lorch.eu
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"are these rehamanns any good? or just box movers??"
I looked at the advert on Ebay for this machine. I have personally never heard of Rehmann and I would find it hard to believe that this machine is made in Germany, (There labour costs are very simerla to the UK) It seems like a play on words. Rehm are a very reputable German manufacturer.
I wonder weather they are imporing kit from China and branding under the name Rehmann, to appeal to Rehm customers.
In anycase, the spec of the machine looks pretty good, duty cycle wise, if these claims are true then it would rival performance from any well known manufacturer.
I guess someone has gotta take a chance and see if they are as good as they claim.
I looked at the advert on Ebay for this machine. I have personally never heard of Rehmann and I would find it hard to believe that this machine is made in Germany, (There labour costs are very simerla to the UK) It seems like a play on words. Rehm are a very reputable German manufacturer.
I wonder weather they are imporing kit from China and branding under the name Rehmann, to appeal to Rehm customers.
In anycase, the spec of the machine looks pretty good, duty cycle wise, if these claims are true then it would rival performance from any well known manufacturer.
I guess someone has gotta take a chance and see if they are as good as they claim.
matt1978
www.lorch.eu
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Just done a websearch for them, couldn't find a manufacturers homepage but they seem to have a few other machines too
http://www.business-industry-supplies.co.uk/Supplies/34095--1.html
http://www.business-industry-supplies.co.uk/Supplies/34095--1.html
mishka
Is it me?
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Matt, that website is simply a front-end to eBay. They make their money on click-through advertising.
Might be worth chasing up the company selling these "Rehmann" machines: Felzen Trading GmbH. Google brings us to this page:
http://www.felzen.com/
Follow through to English->Products->FreeWelding and you end up at
http://www.freewelding.de/
If you look on the "producte" page and click on the link for Inverter TIG DC/MMA and scroll down the window to the table, you see lovely Chinese characters
Might be worth chasing up the company selling these "Rehmann" machines: Felzen Trading GmbH. Google brings us to this page:
http://www.felzen.com/
Follow through to English->Products->FreeWelding and you end up at
http://www.freewelding.de/
If you look on the "producte" page and click on the link for Inverter TIG DC/MMA and scroll down the window to the table, you see lovely Chinese characters
