efficiency % and power factor etc

[Kent]

Looking at putting in some new welding plants and am confused in how I compare power consumption for given output plant to plant.
Can someone with the correct understanding give me an explanation as I am quite willing to spend more on a more power efficient plant if I can only find out how much I can save per KW is there for instance a straight calculation?

 

[piman]

Hello Kent,

you can't directly calculate efficiency, it would have to be measured, or ask the manufacturer for some figures, if they publish them?

Alec

 

[Jim Davey]

You can do it but you'll need to do some research.
Machine power information is printed on the rating plate on the machine.
You will find useful information such as the voltage and current draw for various different output currents, you can then use that information feed into your calculations to give you a meaningful figure such as kilowatts per hour.kwh.
Once you know that you can work out how much a set costs to run per hour.
As a rule of thumb a good inverter is often 20-40% more efficient than an equivalent transformer based machine.

 

[Kent]

Thanks,
I see published efficiency rates for plants around 85% for inverter types does this relate to a calc I can make? I thought there was some laws now on publishing electrical efficiency?

Its a BIG difference to my costs if I can run at 40% less juice in for the same outputs, to be fair enough to maybe say chuck an inverter away after its warranty which sort of totally negates the toughness of transformer base plants

 

[matt1978]

This area is a bit of a minefield to be honest and there are a lot of variables to consider, I know this because we have recently ran a New for Old trade in scheme on the MicorMig range specifically against Transformers. Unfortunately it isn't always true that Inverters are always going to offer big savings against Transformers.

A lot depends on the following......

How old are the machines you are looking to replace, do they have things such as fan and water-cooler on demand?
What size are they regarding amperage output? What are the parameters most commonly used on said machine?
How many hours per day are the machines in "idle" mode as apposed to welding? Most Inverter against Transformer savings appear when the units are in idle mode not so much when they are both welding.

If your serious about looking to change and would consider a Lorch product, I have a plug in meter that will monitor and display your energy use for your existing machines and you could make a direct comparison against a new Lorch equivilient.

After testing numerous makes, ages, sizes of Transformer machines in a 4 hour idle and 4 hour welding day, we anticipated average saving of around £800 per year. But that was welding at around 280 amps with a 1.2mm wire and a 253 average working year and a electricity unit cost of something like 16p.

 

[Kent]

This area is a bit of a minefield to be honest and there are a lot of variables to consider, I know this because we have recently ran a New for Old trade in scheme on the MicorMig range specifically against Transformers. Unfortunately it isn't always true that Inverters are always going to offer big savings against Transformers.

A lot depends on the following......

How old are the machines you are looking to replace, do they have things such as fan and water-cooler on demand?
What size are they regarding amperage output? What are the parameters most commonly used on said machine?
How many hours per day are the machines in "idle" mode as apposed to welding? Most Inverter against Transformer savings appear when the units are in idle mode not so much when they are both welding.

If your serious about looking to change and would consider a Lorch product, I have a plug in meter that will monitor and display your energy use for your existing machines and you could make a direct comparison against a new Lorch equivilient.

After testing numerous makes, ages, sizes of Transformer machines in a 4 hour idle and 4 hour welding day, we anticipated average saving of around £800 per year. But that was welding at around 280 amps with a 1.2mm wire and a 253 average working year and a electricity unit cost of something like 16p.

I have been looking at and tested a Lorch M-pro 252 control pro 230v 250 amp and was reasonably impressed. That was of course a transformer based plant as I am told Lorch do not make an inverter in single phase. It had heck of a good wire feed and I liked it - less sure about the deal I got offered as the torch price for the std binzel was near double what it should be

I don't leave a set on idle unless I am just between welds, if the visor comes off then so does the plant.

The money might not sound a lot when your the one selling a set but even half that £800 notes is the price of the plant over 3 yrs and if you are running say 6 sets if I was the guy doing the selling you better bet I should be shouting about it if my sets were likely to save £800 per annum x6 to the end user.

You meter might be an interesting thing to take round with me during comparison testing LOL

 

[matt1978]

Sorry I didn't realise it was 230v you were talking about. My meter is only for 400v 3ph.

The 252 is the biggest single phase mig we do period. As you said, we don't do a Inverter based 230v at the moment. I'd be interested in your feedback on the 252 compared to other 230v Transformer units of a simerla size because when we launched it stacked up very favourably against the Simerla machines by Lincoln and ESAB at that time, the amperage outputs claimed by some of the units on the market were not "matched" by the voltage available from the Transformer.

It's good that you take time to turn off your machines in Idle mode as it is this idle mode when Transformer machines are most in-efficient. I perhaps didn't make myself clear before a potential saving of £800 per year is really good, I certainly wasn't belittling it. Especially when your looking at multiple machines. But as I said that was a average figure taken from a wide range of Larger Transformer machines some of which were really really in-efficient, and also based on the 4 hour idle period. That's why the potential savings figure was as high as it was. In some instances it would be even higher but in some it would be lower, obviously based in the local conditions.

If your looking at 230v units and you are also ensuring there is virtually no idle time on your existing Transformers, I don't think the potential savings are going to be anything like what your hoping for by switching to an Inverter.

I am not sure if it works the same on 230v but the formula for 3ph is as follow

Average Current draw across the phases (in Amps) x Mains Voltage (should be measured at the socket in the wall) x 1.732 x (efficiency of the machine), then divide the answer by 1000) This will give KwH. When you know how many KwH you can work out how much it costs in real money by multiplying by your electrical cost per unit.

But to be really accurate you need to know the KwH for both welding and idle mode.

And also don't take the efficiency factors quoted by the manufacturer as gospel as when we did our tests there was often quite a large discrepancy between the real and the brochure values

 

[Kent]

Sorry I didn't realise it was 230v you were talking about. My meter is only for 400v 3ph.

The 252 is the biggest single phase mig we do period. As you said, we don't do a Inverter based 230v at the moment. I'd be interested in your feedback on the 252 compared to other 230v Transformer units of a simerla size because when we launched it stacked up very favourably against the Simerla machines by Lincoln and ESAB at that time, the amperage outputs claimed by some of the units on the market were not "matched" by the voltage available from the Transformer.

It's good that you take time to turn off your machines in Idle mode as it is this idle mode when Transformer machines are most in-efficient. I perhaps didn't make myself clear before a potential saving of £800 per year is really good, I certainly wasn't belittling it. Especially when your looking at multiple machines. But as I said that was a average figure taken from a wide range of Larger Transformer machines some of which were really really in-efficient, and also based on the 4 hour idle period. That's why the potential savings figure was as high as it was. In some instances it would be even higher but in some it would be lower, obviously based in the local conditions.

If your looking at 230v units and you are also ensuring there is virtually no idle time on your existing Transformers, I don't think the potential savings are going to be anything like what your hoping for by switching to an Inverter.

I am not sure if it works the same on 230v but the formula for 3ph is as follow

Average Current draw across the phases (in Amps) x Mains Voltage (should be measured at the socket in the wall) x 1.732 x (efficiency of the machine), then divide the answer by 1000) This will give KwH. When you know how many KwH you can work out how much it costs in real money by multiplying by your electrical cost per unit.

But to be really accurate you need to know the KwH for both welding and idle mode.

And also don't take the efficiency factors quoted by the manufacturer as gospel as when we did our tests there was often quite a large discrepancy between the real and the brochure values

Thanks, I thought it should be possible. To be fair I am mainly interested in comparisom percentages less in demand than calculation in savings as you never 100% know how much you will use a plant. I will let you know what I find in testing I have only done a side by side test with the biggest ESAB single phase at present. short term after that its a well known brand inverter and then the guys that claim masses more on single phase (as yet they haven't replied to my question of how this can be done when supply is the important factor)
I will PM you what I think when I have done the main ones, saves upsetting anyone. At present I should love the Lorch but not so sure of the deal offered or the extra costs gives me much that is actually tangible to me personally

 

[Jim Davey]

Quality will be appreciated long after you've forgotten the price.

 

[Kent]

Quality will be appreciated long after you've forgotten the price.

Yes, but these days of globalisation, re-badging etc. price is not always a trustworthy indicator of quality or indeed lack of it.

 

[Jim Davey]

I think it's safe to say that the Lorch will represent better value than an ESAB, if you stack up initial purchase price vs usability and lifespan.
That's why I put the best gear I can afford on my rental fleet, it takes a little longer to break even but the hassle free running and happy customers are more important to me than the purchase price (within reason)

 

[Kent]

I think it's safe to say that the Lorch will represent better value than an ESAB, if you stack up initial purchase price vs usability and lifespan.
That's why I put the best gear I can afford on my rental fleet, it takes a little longer to break even but the hassle free running and happy customers are more important to me than the purchase price (within reason)

debateable, I have run ESABs through hell and back. the wire feed is better on the lorch, the box is better, welds are non the less equal with 0.8mm and gas

 

[Jim Davey]

I haven't come across an ESAB I liked yet.

 

[Jim Davey]

I'll amend that to I haven't come across a modern ESAB a I liked.

 

[Kent]

Each of us has an opinion. After being involved in "branding" sales and marketing for so long I am a bit sceptical of being too drawn in hence I test before I buy. In the dept of running a good bead and duty there is no difference in an old ex-hire ESAB 250 amp and the equivalent brand new lorch bar the lorch could be expected to run ali better with its better 4 roller feed system and if you didn't know what setting was right the Lorch was semi synergic (for German gas at least, it was well on the hot side).
At the end of the day though I might well buy the Lorch but it will be based on hard facts and tangible differences to my needs

 

[Jim Davey]

The 10 year obsolescence policy on its own is enough to make me give used ESABs a wide berth.
But as you say, you've got to choose a machine on its individual merits.
By the way, all synergic machines seem to weld on the hot side. This is because the power calculation for the synergic curve is normal based on a fillet weld (this takes more energy than a butt or a lap of the same thickness of material) then I think they add a little margin as a safety factor (nobody wants to be sued when your 'cold' weld fails and hurts someone). I tend to take metal thickness guide settings as just that, a very approximate guide. What's more important is that the wire feed matches the chosen voltage without too much faffing about trimming it to suit, this is where synergic sets really shine, quick changes from one settings to the next with little or no fiddling to get the condition right.

 

[brightspark]

I think it's safe to say that the Lorch will represent better value than an ESAB, if you stack up initial purchase price vs usability and lifespan.
That's why I put the best gear I can afford on my rental fleet, it takes a little longer to break even but the hassle free running and happy customers are more important to me than the purchase price (within reason)

thats my thinking when buying tools. if a hire company hires them out they must be half decent and need to be reliable

 

[Jim Davey]

That's how we've always done it. Hire kit has been a mix of Murex (back when that meant something) Rowan -Arc (doubt anyone remembers them) Camarc, Eutectic, Messer Greshiem, Fronius, Lincoln Electric, Newarc and most recently EWM.
Never had a Butters on the fleet, the old ones were great though, built like tanks.

Edit: I forgot, we had a couple of Cebora Boxer 155s that went out to weekend warriors, they lasted donkeys years and a few Merkles, big water cooled pulse MIGS from back in the eighties, and some Syncrowaves plus a couple of Sabre-Arc mixed gas 150 amp plasma cutters, I was a child when we got rid of those though.