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Forum Index : Electronics : 24 volt inverter
| Author | Message | ||||
Bryan1 Guru  Joined: 22/02/2006 Location: AustraliaPosts: 1204 |
G'day Guy's, Well today mny trusty Kipoint inverter refused to power this new mig I bought and I do feel after 15 years this inverter is on it's last leg's. So I am asking if any of you guys make or have one spare after you made a few, would be able to supply me with a new inverter. From what I've read the Oz inverter is the bee's knee's but with my bad luck of trying to source toriods I am willing to pay for a member to build me one. I have told my wife we need to upgrade so a 48 volt one will also come with the request. So if any member can help out it would be great as spending a heap in chinese stuff isn't a option. Regards Bryan |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
I think the biggest problem anyone has is getting hold of the torroids. Probably better to get a custom one wound, if you could get a few interested having an order of 5 or more might make the price slightly less painful. Cheers Caveman Mark Off grid eastern Melb |
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andymc70 Regular Member  Joined: 30/06/2019 Location: AustraliaPosts: 42 |
This maybe a stupid question but what are the cores actually made from and can they be made from any ferrous metal. I saw this video and wonder if anyone has tried to build there own cores here. https://www.youtube.com/watch?v=Bbv1iXadEv4 I see that the annealing process is just a heat treatment. Just wondering what other people thoughts. If you can find an overseas company,I did find one i will need to do a search for them, i do have logistic contacts that maybe able to get them here. Not sure of costs however. |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
OK, First, they are out there. Find a solar installer near you and call him .. (They remove faulty ones, that is solar inverters, often. ). Now ,tell him you are interested in only the very heavy inverters that he has removed--Clue, these will be the ones that have the very heavy Torodial coils-forget the rest~. Ok , a case of beer may help , because he gets scrap copper money from his recycler ... Now when you get one , he might just give you the whole inverter , you'll have to dismantle it -thats easy, but sometimes the Torodial pose a problem when it comes to removing the outside winding-you see, the manufacturer fills the core -after winding , with epoxy putty. I drilled, carefully, mine out ,until I could gently tap the core out . So, winding the primary on the outside, thats a new story ---get back to me when you get this far .. Bruce Bushboy |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
There are a few kicking around, I have about 10 local installers that know I want them. Mostly the 1 and 2kw units are the ones that appear, if they could be bothered contacting you. Don't forget these guys are in business to make money, not do favours for someone they never met, even $50 or a slab isn't really worth their time to arrange to take it back to their shop, find your number,ring you, then deal with you to pay and collect. The ones that I have got them from I tell them that I make inverters from them, sometimes they get a bit curious about how you do it and take an interest. That's the best way to get them to play ball I found. Back when the aerosharps were being installed the 3kw units would have been considered VERY big and expensive units. Back then a 3kw system was horrendously expensive. So there were never millions of them floating around. Down here in Melbourne ther would have been fairly few, up the coast where take up is 10 times as much you would have a far better chance. Andy, they are made up from incredibly thin silicone steel that is wound super tight and heat treated. Not something that can be done in the garage. Buying them at a reasonable price isn't the main issue, it's the freight. You could get one for probably $400, but shipping will be $500 Warp got a custom set of E I cores made for his warpinverter. But I don't see why you couldn't buy the bobbin and cores yourself and assemble it at home to save a few bucks. But nothing will ever get it wound as tight and neat as a machine. Cheers Caveman Mark Off grid eastern Melb |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
The big toroids are available brand new, but they are not stocked in any standard sizes as you might expect. In fact AEM (in South Australia) don't carry any stock at all. Its a case of "give us the dimensions you want, and we will run off a few". They are wound individually to order, any size you want, from really small, up to about 300 Kg in size. If you wanted a hundred toroids, the cost would likely be very reasonable. If you want only one, I suspect the setup charge, and delivery cost would be a bit discouraging, although I have never asked them for a quote. They are really set up for large scale production, not us crazy hobbyists. Cheers, Tony. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Three years ago, the stamped silicon iron E and I laminations were about $18.50 per Kg trade price. A similar sized toroid would be less than that, but not a lot less, its the same stuff. Its cheaper to wind a long ribbon into a toroid, than stamp out laminations one at a time on a 100 ton press. Copper wire was also very close to the same cost as the steel per Kg. So if you are winding a 80Kg transformer, just the materials alone will come to over fifteen hundred dollars if buying new stuff. Cheers, Tony. |
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Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 961 |
Bryan, I think it might be worth taking a look inside your inverter, see if any components are dirty or degraded. Also have a look at the transformer (what type it is) and see if it suitable to use for a new inverter, could be as easy as winding a few more turns on the primary if it is on the outside layer and if there is enough room, if that's ok it would be worth looking into getting a control and power board to suit. Ok that's a few IF's....this is probably your main inverter and you would need a backup unit to keep the place going.  Cheers Aaron Off The Grid |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1204 |
G'day Guy's, Well the inverter is still going and it powers my tig nicely but what I have found with no real load ( only my shed lights) on measuring the voltage it's around 198 volts. Now as soon as I powerup my Lincoln i130 arc/tig the shed lights brighen and the voltage is back on 240-250 volts. Now this inverter is supposed to have a 8Kw surge but over the years the surge has gone down to the point I can't even start my 8" grinder without the inverter complaining of over current. A few times my toolroom VFD used to go into fault mode when turned on and when I measured the voltage it was 350 volts  so on the inverter I found a trim pot to turn down the voltage and that cured the VFD problem.Now I'm not sure if this is enough detail to go off to find the problem but hopefully it will give an insite into the problem. Cheers Bryan |
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| mab1 Senior Member  Joined: 10/02/2015 Location: United KingdomPosts: 149 |
Difficult to think of a single problem that could cause all that! I guess you've already checked all the power connections are sound - a dodgy connection might explain a lack or surge capability - as would an aged battery perhaps. the voltage issues might suggest a bad joint/component in the voltage feedback loop - or the voltage trimpot has gone flaky? The only other thing I could think of the try if it was mine would be to check/replace the capacitors - the big input ones for surge capability (and voltage stability), and the smaller unpolarised ones filtering the output which could affect the voltage feedback loop iof there's a lot of high frequency ripple getting through. Just guesses i'm afraid, but without it on the bench in front of me to probe and test I can't rule much out. Do you have a 'scope to see the output waveform? I'm assuming it's pure sinewave not MSW? Do you know if it's low frequency (big transformer) or dual conversion type? |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1204 |
Hi Mab, Back in '05 I emailed Kipoint and asked them for a 3Kw pure sinewave inverter with the same spec's as our Selectronic SA32 inverter. I got an email back asking if I wanted a LCD I where I replied no thanks as thats a part that will fail over time. About 7 weeks later I got an email saying they had designed an inverter to my spec's and offered me the first one for $800. When I imported the inverter I got a call from customs asking what it was as they didn't have a listing for inverters and I got charged $500 for import duty. I did email Kipoint about a year ago asking for a schematic where I was told they never made that inverter. After a few emails we got to the bottom of it where they told me the engineer that designed that inverter went out on his own and has no further business with Kipoint. When i probe the mains with my fluke 865 scope meter it does show a pure sinewave and on taking the cover off there are no signs of blown caps or any damage at all. There is nice size toroid onboard and a decent cap bank with a small control board attached to the main board. Cheers Bryan |
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| mab1 Senior Member Joined: 10/02/2015 Location: United KingdomPosts: 149 |
OK the big Toroid would suggest it's a low frequency type. Hmm, well, caps looking ok doesn't prove they are ok, but if we assume for the moment it isn't the caps, then i'd be focussing on the voltage feedback components as there are clearly some output voltage issues. I'd check the components individually, but it's difficult to know what to do without knowing more about the feedback cct. was the scope waveform taken at no load or light load (shed lights) or substantial load?Does the output voltage vary consistently from light load to heavy, or does change behaviour from day to day? You say there's a small control board attached to the mainboard? Is it securely connected to the mainboard? no corroded contacts or cracked solder joints? I don't suppose it would be an EGS002 board at that age? |
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Haxby Guru Joined: 07/07/2008 Location: AustraliaPosts: 418 |
It might be hard to track down the regulation fault from that era of inverter. I wonder if you could throw out the old electronics but keep the transformer and buy a ready made 48v board from Ali express. Then if there is enough space on the transformer, add some windings to make it a 48v transformer? |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1204 |
That isn't the go for me as I run 24 volts and have done since '04, when I setup the system 48 volt systems wasn't around. Now I use a 24 volt 735AH traction battery and for me to goto 48 volts would mean buying new batteries which isn't on the cards. These forklift batteries will last 20 years in a off grid system easily as the majority of the time the incoming power power exceeds the out going power and my dump load is a 24 volt fridge. When I have some spare time I'll take the cover off and take some photos which should give the general overview of this inverter. Cheers Bryan |
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| noneyabussiness Guru Joined: 31/07/2017 Location: AustraliaPosts: 506 |
24v eg8010 board They come in 24v flavours.... I think it works !! |
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| nickskethisniks Guru Joined: 17/10/2017 Location: BelgiumPosts: 409 |
Like you say, I would start with the filterstage in the voltage feedback is it with a transformer or opto? Then check the output filter. 15y old buffer capacitors can't hurt to replace them, but could be expensive. I know some of the victron inverters test the voltage ripple, this will only get higher overtime, so with older components. So start with the cheaper components. A bad cosinus can influence your voltage output/feedback too, as well as the kind of load you are putting on it. |
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