EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: freeelectrons on July 07, 2023, 08:52:25 pm
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Hey Everyone,
I am currently looking for a high current ac source. I currently(lol) use a current source with a transformer to step down and provide a high current output. The only equipment I have come across is Zenone https://www.zenoneelettronica.it/indexe.html (https://www.zenoneelettronica.it/indexe.html). Is anyone aware of other options?
Thanks!
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I´m looking for something... ;)
More details please.
How much current (min, max/peak, duration), frequency, for what to use..
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you can use mains, it supports pretty high AC current :)
If you're needs more, like continuous megawatt power consumption, you can ask your local energy company for a dedicated high voltage line to your apparatus...
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Hopefully this is not just another company trying to drum up traffic to their site...
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Hopefully this is not just another company trying to drum up traffic to their site...
It probably is, otherwise an AC arc welder is a rather obvious choice.
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I can not imagine, the products that Zenone manufactures cost not exactly little (we once asked a 200kVA supply, which costs 6-digit), here they would rather not find a target group for it.
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I´m looking for something... ;)
More details please.
How much current (min, max/peak, duration), frequency, for what to use..
Up to constant 400 amps rms. The load is essentially a short so i would need to control current from the source programmatically. Sub 1200hz for harmonics testing but 60hz fundamental.
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It probably is, otherwise an AC arc welder is a rather obvious choice.
It would be interesting to develop a solution from a welder. After looking at prices it makes more sense to go directly with a ac source and transformer.
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It does not seem like there are many accurate programmable ac current sources available.
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Kikusui make big, programmable AC supplies: https://global.kikusui.co.jp/products-index/ac/
Some of the series can be paralleled to provide rather substantial amounts of programmable current. You might need an on site generator to power them, if your AC supply isn't capable and the utility doesn't want to give you a few hundred kW supply. Hyundai gensets are probably cheaper than a supply upgrade too.
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ITECH China has the IT7800 which can be paralleled for high current. Won't be cheap, but it may be cheaper than the other (non DIY) options mentioned.
https://itechate.com/en/product/ac-power-supply/IT7800.html
I have no experience with these large units, but do I have a little ITECH IT7321 Programmable AC PSU on my bench.
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For higher current simulations we use a transformer with one additonal winding on the core.
We get nearly 100A this way while only 1A primary current is flowing.
So buying a welding transformer and feed him with a low/medium power source ist the cheapest way to gain the 400A current.
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So buying a welding transformer and feed him with a low/medium power source ist the cheapest way to gain the 400A current.
Hmm, my 400A AC 2 phase stick welder cost me just $200.
Duty cycle at full tit is another consideration fan cooled or not.
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It does not seem like there are many accurate programmable ac current sources available.
Oh yes there are! Pacific Scientific and Elgar just to name two of them. I don't know how high their current ratings are but they are very accurate voltage and frequency wise and they are programmable. I THINK you can also couple several Elgar units together to increase their current output and drive all of them from a single control module. What kind of voltage output do you need? 400 amps is a lot of current and if you need that amount at any significant voltage, it's going to be a hell of a lot of Power! If you just need a volt or two then you might be able to use an Elgar 251 or one of their 750 Watt models set to say 110 VAC and use that to drive a transformer that will give 400 Amps at 1/2 to 1 volt AC. I've used the Elgar 251s and some of the PS units and I know that Elgar makes a 750 Watt output model and I think they make larger models but I have no experience with them.
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For higher current simulations we use a transformer with one additonal winding on the core.
We get nearly 100A this way while only 1A primary current is flowing.
So buying a welding transformer and feed him with a low/medium power source ist the cheapest way to gain the 400A current.
Any links or recommendations?
We use the secondary of this transformer https://www.tescometering.com/product/loading-transformer/ (https://www.tescometering.com/product/loading-transformer/) like an auto transformer to double our current but compliance voltage begins to be a concern.
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Played with one of these once, https://www.amp-line.com/ (https://www.amp-line.com/)
Well built, easy enough to use, programmable, very heavy...
Specifically, a 2V 1000A single phase model. For testing power line current sensors. I think the bulk of the weight was the output transformer. Hm, it was 208/240V input, though I forget if we were using 3ph on it (industrial application, we had it available of course).
Tim
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Hmm, my 400A AC 2 phase stick welder cost me just $200.
Duty cycle at full tit is another consideration fan cooled or not.
Any links?
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It does not seem like there are many accurate programmable ac current sources available.
Oh yes there are! Pacific Scientific and Elgar just to name two of them. I don't know how high their current ratings are but they are very accurate voltage and frequency wise and they are programmable. I THINK you can also couple several Elgar units together to increase their current output and drive all of them from a single control module. What kind of voltage output do you need? 400 amps is a lot of current and if you need that amount at any significant voltage, it's going to be a hell of a lot of Power! If you just need a volt or two then you might be able to use an Elgar 251 or one of their 750 Watt models set to say 110 VAC and use that to drive a transformer that will give 400 Amps at 1/2 to 1 volt AC. I've used the Elgar 251s and some of the PS units and I know that Elgar makes a 750 Watt output model and I think they make larger models but I have no experience with them.
Ill check them out. Compliance voltage I would expect to be no larger than 10V. I also looked for a transformer to drive that level of current and did not find any options. Elgar was purchased by ametek.
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So buying a welding transformer and feed him with a low/medium power source ist the cheapest way to gain the 400A current.
Hmm, my 400A AC 2 phase stick welder cost me just $200.
Duty cycle at full tit is another consideration fan cooled or not.
I think I remember my girl telling me that same story... :-DD
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Hmm, my 400A AC 2 phase stick welder cost me just $200.
Duty cycle at full tit is another consideration fan cooled or not.
Any links?
Got mine via our local online auction site, older but in good order.
Google Transarc 400 welder for examples but they will mostly be NZ/AU locations.
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Older or not, full tit is usually always good... :-+
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Older or not, full tit is usually always good... :-+
Ever used a 400A welder running at full tit ?
If not you are in for an experience.......300A is as hard as I've used and that ate 6g rods for breakfast ! :o
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Well when it comes to full tit, I have no experience with Arc welders, so wouldn't know. Now up here there is a difference between tit, and tilt, so that could make an upside down world of difference!
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Hmm, my 400A AC 2 phase stick welder cost me just $200.
Duty cycle at full tit is another consideration fan cooled or not.
You can always parallel two welding machines, AC or DC. I have a couple of Millers that I've done that with a few times when using jet rods.
It's a lot easier on the machines when they are sharing the load.
WoD
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Ever used a 400A welder running at full tit ?
If not you are in for an experience.......300A is as hard as I've used and that ate 6g rods for breakfast ! :o
Yes! Both jet rods and arc gouging! :(
Most people would never believe the heat generated by either of these at those current levels. A white pipe-liner hood is noticeably cooler than a grey or black one.
WoD
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Hmm, my 400A AC 2 phase stick welder cost me just $200.
Duty cycle at full tit is another consideration fan cooled or not.
You can always parallel two welding machines, AC or DC. I have a couple of Millers that I've done that with a few times when using jet rods.
It's a lot easier on the machines when they are sharing the load.
WoD
Quote fixed.
Fine if you have 2 similarly capable welders however I never have.
For a while I had a 180A, 300A and a 250A DC TIG however they all had different control circuitry of which I would never dare to run them in parallel. :scared:
Now with just the big 400A on castors and a 180A MIG, 140A caddy and gas set there's not much I can't handle. TIG I don't really need.
The big 400A was needed for the occasional heavy fab job however most of its work is just maintenance and repair.
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Mind that welders aren't likely very clean (stability or output ripple), nor very well calibrated. At low frequencies they should be fairly stable/consistent at least (since that would affect usability if not!). Output V(I) characteristics likely not well controlled either, other than being somewhere resistive to CC for TIG/stick types, and lower resistance for MIG.
Kind of a similar thing with electrophoresis supplies, AFAIK they're quite noisy/nasty because it doesn't matter for just pulling charge through a solution.
Tim
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There's a pool of designs Tim ranging from tapped primaries, choked outputs, phase control and what could best described as SMPS.
Every dog of these designs has their advantages, power vs weight, fanless and just the plain efficiency latest designs offer.
Pick your poison !
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Ever used a 400A welder running at full tit ?
If not you are in for an experience.......300A is as hard as I've used and that ate 6g rods for breakfast ! :o
Yes! Both jet rods and arc gouging! :(
Most people would never believe the heat generated by either of these at those current levels. A white pipe-liner hood is noticeably cooler than a grey or black one.
WoD
I have a Miller SynchroWave 350 and if I remember correctly it requires 130 Amps at 240 VAC at full tit. That's a LOT of power!
I don't know what voltage the OP requires but he will need something close to the size of the 350 to get 400 Amps. I don't recall the exact weight of the 350 but IIRC it's between 650 and 800 pounds.
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Fine if you have 2 similarly capable welders however I never have.
For a while I had a 180A, 300A and a 250A DC TIG however they all had different control circuitry of which I would never dare to run them in parallel. :scared:
Now with just the big 400A on castors and a 180A MIG, 140A caddy and gas set there's not much I can't handle. TIG I don't really need.
The big 400A was needed for the occasional heavy fab job however most of its work is just maintenance and repair.
No control circuitry in either of these. One is straight AC and one is and AC/DC machine. Easy to parallel when running AC.
Lincoln engine driven SA-200 and 300 DC machines even easier to parallel. None of that phase stuff to have to pay attention to. :)
I've paralleled a pair of gasoline driven 5000 watt AC generators before, too.
You got me to thinking about all that heat. Somewhere around here I still have a pair of thick gauntlet style asbestos gloves. Most people today wouldn't even recognize them for what they are. I doubt you could even buy a pair if your life depended on it.
WoD
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I've paralleled a pair of gasoline driven 5000 watt AC generators before, too.
:o
With no regard to phasing ? :scared:
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Fine if you have 2 similarly capable welders however I never have.
For a while I had a 180A, 300A and a 250A DC TIG however they all had different control circuitry of which I would never dare to run them in parallel. :scared:
Now with just the big 400A on castors and a 180A MIG, 140A caddy and gas set there's not much I can't handle. TIG I don't really need.
The big 400A was needed for the occasional heavy fab job however most of its work is just maintenance and repair.
No control circuitry in either of these. One is straight AC and one is and AC/DC machine. Easy to parallel when running AC.
Lincoln engine driven SA-200 and 300 DC machines even easier to parallel. None of that phase stuff to have to pay attention to. :)
I've paralleled a pair of gasoline driven 5000 watt AC generators before, too.
You got me to thinking about all that heat. Somewhere around here I still have a pair of thick gauntlet style asbestos gloves. Most people today wouldn't even recognize them for what they are. I doubt you could even buy a pair if your life depended on it.
WoD
https://www.ebay.com/itm/126008474979?hash=item1d56b0bd63:g:df0AAOSwAzNkn3it&amdata=enc%3AAQAIAAAAwNh26bYIlfCyMPcpMMkmEpvJXZLVaDauFN9up%2F1MntbTuEPzevnf3v7BV%2BfJ%2FidgNH8Zc04wvtOZDd%2Bi5ZMs61JJPNEeZ6TKFJB0GMWCsYyeB1mU8awthADWNqCNicAOIwuSNwC%2BslsJaSCGVbQ7jRk1tFXnJ5dNT16H5moTJVgevXvTIc4gyRz3En0P3EfJSyIsLxyxSTs97helb0JTt4rx9NAsQXVKUtiVfX%2BkRA50ZiIQpXp2DQJ6EjSphNqUxQ%3D%3D%7Ctkp%3ABk9SR7qYl-CnYg (https://www.ebay.com/itm/126008474979?hash=item1d56b0bd63:g:df0AAOSwAzNkn3it&amdata=enc%3AAQAIAAAAwNh26bYIlfCyMPcpMMkmEpvJXZLVaDauFN9up%2F1MntbTuEPzevnf3v7BV%2BfJ%2FidgNH8Zc04wvtOZDd%2Bi5ZMs61JJPNEeZ6TKFJB0GMWCsYyeB1mU8awthADWNqCNicAOIwuSNwC%2BslsJaSCGVbQ7jRk1tFXnJ5dNT16H5moTJVgevXvTIc4gyRz3En0P3EfJSyIsLxyxSTs97helb0JTt4rx9NAsQXVKUtiVfX%2BkRA50ZiIQpXp2DQJ6EjSphNqUxQ%3D%3D%7Ctkp%3ABk9SR7qYl-CnYg)
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I've paralleled a pair of gasoline driven 5000 watt AC generators before, too.
:o
With no regard to phasing ? :scared:
No, you have to pay attention to phasing with AC.
WoD
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I've paralleled a pair of gasoline driven 5000 watt AC generators before, too.
:o
With no regard to phasing ? :scared:
No, you have to pay attention to phasing with AC.
WoD
And rev matching too for them to properly share the load.
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And rev matching too for them to properly share the load.
Both need to be turning the same speed to match the frequency. Once they have synced, they will tend to stay that way. Same frequency, same speed, same rpm.
Rotor current/voltage could be tinkered with to tweak the actual output voltage, but not speed. I did that some years back on my PTO driven genset. I changed the value of a couple of capacitors to lower the output voltage by five volts or so.
I just had a thought. Since 60Hz is the standard here, most generators run at either 1800 or 3600 rpm. You guys have a 50Hz standard. I'm guessing that gensets there run at 1500 or 3000 rpm. It'll take a more engine to product the same number of watts at a lower speed.
WoD
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If the impedance of the thing you are testing is low enough, you could use a current transformer (eg 1000/5A secondary), connected in reverse. Years ago, I saw a switchgear manufacturer do primary current injection tests on busbar this way, although I don’t remember the details.
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I use toroidal transformer with 2 turns of 250 mm2 secondary.
600 A for long time, up to 1600 A for short time.
Limit is in secondary thickness, but it is scalable. Output voltage is less than 5 V. Very simplistic yet not super stable as mains dependant.