Inverter v Transformer

[RichH]

Hi All
New to the forum although have been a watcher for some time. I'm looking to try some TIG welding and have spent some time looking at various reviews and comments on different machines. One thing I haven't got to grips with is the difference between inverter and transformer machines. I understand that the inverter type are likely to be smaller and lighter but what are the pros and cons between the two styles?
Would appreciate any help and guidance.
Thanks, Rich

 

[chevy2]

A few details,
Inverters are generally smaller and lighter yes,
need far less input current from the mains to run them so more suitable for running off domestic supplies... and cheaper.

Transformers, yes larger and less portable but many rate them as more reliable as they dont have the electronics to get dust damage etc.

 

[KemppiFrog]

And.. transformers tend to be old school quality kit. while inverters are newer and often built in China and are of varying quality. So a good name and aftersales are important.

 

[shenion]

Transformer units are relatively simple and can last decades. They cant change the frequency but may have most other features. My transformer beast is now 40 years old. Some do have electronics for pulse, slope etc and that may be hard to maintain long-term (finding circuit boards.)

Inverters are software-controlled so they can vary the frequency. They use switching controller like a PC power supply. Also have power-factor correction for reduced current draw. They are complicated and often cant be fixed easily other than replacing expensive boards.

Both you should consider the seller support for repairs. A Chinese TIG box seller will want you to send the unit back to China at your cost. A good rep will have local service and stand by their products.

My beast works fine. An inverter would help on thin metal as I could run it at higher frequency to better focus the current.

 

[zardoz]

On the whole I would say. Get a meduim sized transformer kit, unless....

You can afford a well respected make of inverter, such as Lorch, Lincoln, or Kempi etc. For one of those you will pay a premium. However it is much more likely to be able to get spares for if it breaks in the distant future (ie: when the 2 years gurantee has run out)

Or if you are going to do all your welding at home, just get a big old transformer like a Portamig or something similar. Or even something bigger, that you can use as a TIG/MIA/MMA, such as a huge Miller Synchrowave 500 with all the bells and whistles on it. You might be rather hampered in this unless you have 400Volts three phase power though. If you are lucky enough to have it though, go for it. I have raged and shook my first at the elctricity supplier gods, at the lack of 3 phase to my house, as I have watched many a huge 3 phase welder go for a song on ebay.

 

[hotrodder]

The Murex Transtig 252 (ESAB heliarc 252 in disguise) in a mates workshop popped one of it's PCBs the other year despite being a basic spec transformer (no digital meters or pulse etc). Granted the PCBs are small, simple things compared to an inverter that's stuffed full of things but... Machines of this size are capable of pulling 100A out of the wall running flat out on 230V!

Smaller transformers like the Portamig TecTig mentioned want a 40A fuse to provide 200A output with a 35% duty cycle (150A @ 60%). Weighs 70kg
My Lincoln v205t wants a 16A fuse* for 200A @ 40% (170A @ 60%, 140A @ 100%) and can be picked up easily with one hand complete with it's water cooler bolted to the base

Inverters also offer arc shaping (AC frequency, high frequency pulsing both of which constrict and stiffen the arc. Transformers can offer pulse but not at 100s of Hz) neither of which are necessary but they are very useful the former on ally the later on thin stuff, especially heat sensitive materials like stainless. The downside is they're horrifically complicated and thus more expensive- to buy and to fix. Having said that mine is over 13 years old now, been dropped more than once and still going strong. Lorch even make their kit specifically 'crash proof'... http://www.mig-welding.co.uk/forum/showthread.php?t=17044


* On paper, in practice it's happy enough running flat out on a 13A plug

 

[zardoz]

Having said that mine is over 13 years old now, been dropped more than once and still going strong. Lorch even make their kit specifically 'crash proof'... http://www.mig-welding.co.uk/forum/showthread.php?t=17044

A Lorch! Ahhh I dream of owning an AC/DC Lorch inverter. If i win the lottery that will be the first purchase to go in to my purpose built workshop.

Maybe one day..... one day..

 

[matt1978]

That's the Handy (MMA Inverter) and the HandyTig 180 DC as they share the same housing in that video, 80cm crash proof.

There is a Simerla forum to this one in Belgium and they did there own test on a HandyTig ACDC.

http://youtu.be/q0BEZ_daXVo

This is a larger housing which is common on the 180-200 HandyTig ACDC and on the 180-220-250 & 300 T series versions. That can be dropped from 60cm.

 

[zardoz]

I dunno. There are quite a few bits of edge on the floor after he's finsihed poking it with a stick. Maybe hardedned rubber would be the way to go rather than so called 'shaterproof' plastic.

I'd still love a Lorch though. Dont suppose you are doing any demonstrations in the North West in the near future are you?

 

[RichH]

Thanks for the replies guys.

I'm still in the "deciding" stage and as I don't have any particular projects in mind apart from wanting to have a go at ally welding I'm still not sure. Whilst leaning towards the "old school" I'm just wondering if the inverter would be more suitable because of the additional features. Do they make that much of a difference? As a complete novice at TIG welding it all gets a little confusing to my limited grey matter!!

To be honest I was looking at something around 1k and had in mind machines like the R-Tech 200amp AC/DC, the TEC-ARC 216i or the Portamig TEC-TIG 185.

What's the general concencus as a machine for learning on?

Thanks again for your attention.

Cheers, Rich

 

[matt1978]

I dunno. There are quite a few bits of edge on the floor after he's finsihed poking it with a stick. Maybe hardedned rubber would be the way to go rather than so called 'shaterproof' plastic.

I'd still love a Lorch though. Dont suppose you are doing any demonstrations in the North West in the near future are you?

The crash proof thing does not mean that the front and rear grilles won't become damaged, they can be replaced fairly easily and cheaply. The point is that the insides (expensive parts) are still fully functional and that's what's protected.

The difference is that if you take a competitors machine and drop it from the same height, you'll still have the broken plastic bits on the floor but worse than that the gubbins inside will be wracked off aswell and likely to be scrap.

I do demos in the North West quite often

 

[zardoz]

The crash proof thing does not mean that the front and rear grilles won't become damaged, they can be replaced fairly easily and cheaply. The point is that the insides (expensive parts) are still fully functional and that's what's protected.

The difference is that if you take a competitors machine and drop it from the same height, you'll still have the broken plastic bits on the floor but worse than that the gubbins inside will be wracked off aswell and likely to be scrap.

I do demos in the North West quite often

Indeed, as you say the important bits are inside the casing. I was just pondering whether hard rubber might be better than plastic, for the edging.

The next time you do a demo anywhere within 30 miles of Chester, and if its ok for me to come along. Please let me know.