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Forum Index : Electronics : Small Toroid Inverter
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Bryan1 Guru  Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Thanks for the tips guy's so lets say I do go with 2 turns a volt so that would make 480 turns and using that 1.6mm wire I could get roughly 100 turns each layer. Now with 5 layers allowing for the mylar insulation that would only be about 8.5mm height of the coil. So I do think going 2 inhand for the secondary would still leave plenty of room for the primary which I still need to work out to suit the 24 volt system I have here. Now most will say why not go 48 volts well the simple fact I run forklift batteries and they have been going strong for over 10 years and I do expect to get another 10 years out of them. When we went off the grid in '04 48 volt systems wasn't even a reality let alaone the norm. Cheers Bryan Edit: going with 240 volts 50 hz 480 turns and 10 amp current Tesla 0.4568 Gauss 4568.46 |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
I am as thick as two short planks! To work out the number of turns just count the number on the existing 240V coil! Edit If you have the time and inclination you can determine the exact properties of the core here:- https://au.mathworks.com/help/sps/ug/custom-transformer-b-h-curve.html;jsessionid=505d62b91ccae9cb0e50085c8791 In their example transformer the core can support 1 Tesla or 10,000 Gauss. Your core was probably designed quite a long time ago, and to a budget so they may have used a lower grade of steel. So my original guess of 1.5 turns / volt, 6000 Gauss might not be too far off. edit 2. A bit more digging. It seems I have been too conservative , 1 turn / volt might be possible. Edited 2022-12-31 08:26 by phil99 |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Phill that link was way over my head mate  Now as I did still have that page up for the maximum Flux density I put in 240 turns and the result was Tesla 0.9137 Gauss 9136.93 So todays fun is going to be stripping those old coils and see if I can get a count on that 2.5mm wire used for the secondary and hopefully rescue that 8x5mm wire to use as the new primary. Cheers Bryan Edit: got the first run of the primary out and counted 24 turns so got a nice big job of cleaning up the wire off the old epoxy and get a total length. Time to start on the secondary. Edited 2022-12-31 09:40 by Bryan1 |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Ok with the secondary there was 2 short turns and one long one where I roughly counted about 300 turns. With the primary wire I stripped off the 2 layers of tape which did take a couple of hours and I'll machine up some reforming rollers so i can get the 8x5mm wire nice and straight so it will sit on a spool. Cheers Bryan |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
"Ok with the secondary there was 2 short turns and one long one where I roughly counted about 300 turns." Yes, your photo of the terminal labels:- N -6% 240 +6% A E which would be to adjust for local mains voltage. Suggests the short coils should be 6% of 300 turns = 18 turns. Any way you now know you need 1.25 turns / volt, halfway between my last two guesses. |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Thanks for that Phill now I did do some sums on my 1.6mm wire spools and with one weighing in at 2.8kg with the other 3kg I have more than enough to go 2 in hand for the secondary as the 1.6mm wire is 56 metres to the Kg. For the primary I reckon 400 amp welding cable will fit in nicely. As I've said I do need a board and I looked at that one in the For Sale section Murphies Friend put up. So if you guy's reckon it will do I'll get onto it ASAP in the hope it is still there. Cheers Bryan |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
He will know much more about it's suitability, I have only made smaller modified square wave inverters. Most small appliances including the fridge seem happy with that. Some LED and compact fluorescent lights don't like it though. |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
G'Day Guy's, Well with 38C in the shed not too much will get done today so i'm on thinking about the former I'll use to wind the coil. I do reckon making the former 3mm bigger so it can slide together easy. I do need to get this gap right as I will be using my lathe to wind the secondary so I can get the wire nice and uniform. So a wrap of mylar around the former then wind on the first layer then mix some some fiberglass resin to paint onto the coils and while still wet put the next layer of mylar on. Rinse and repeat on every layer until 300 turns is complete. Now going 2 in hand I can get 50 turns so the secondary will be 6 layers high then when trial assembled I can check the gap left and source the primary wire so it ends up a snug fit. Now looking at aliexpress there are 100's of these driver boards so finding the right one to suit is a challenge. Cheers Bryan |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Well I think I just answered my own question board kit US$11 for a board and full kit of parts then some soldering fun. It also has the EGS8010 driver board. Cheers Bryan Edited 2023-01-01 14:25 by Bryan1 |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 458 |
Hi Bryan, the kits look really cheap. I have three inverters with those Aliexpress boards. I bought mine already assembled. I think mine are 3kw 24 volt boards. I managed to blow up PowerJack inverters at least 3 times. Got sick of fixing mine. They seemed to dislike my dropsaw mostly. Since having those Aliexpress 8010 boards , no blowups at all. I did modify the 8010 boards as per Oztules recommendations and disabled some functions that Noneyabusiness suggested too. They work great. I run my air compressor, woodsplitter, dropsaw, all my power tools and no problems at all. Been about 3 years for one of them now with no faults. I rewound some of my powerjack transformers from the inverters that died. I used 6mm solar panel cable on my secondaries. Pete |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Hi Pete, I've been looking around that sellers store and they do have kits with more fets but as always what is the quality of the parts is yet to be determined. Now with the outputs being in Chinglish I'm sure we can decipher those easily. Now what has me intrigued is the IGBPT boards they have all the way upto 8Kw The ultimate goal with this project is too see if it will power my mig a Viper 183 amp that use's 5kg spools. One night I used this mig powered off my Listeroid and it let out the magic smoke and I got the mig done under warranty as I just said when I turned it on it went snap crackle pop  Now when I wind this coil I will see if my daughter can make a video which will be entertaining at least. Cheers Bryan EDIT: I did try and use the search engine on this forum to find Oxtules original thread with no luck infact if I need to find a post it's a long haul as the search engine is buggered Edited 2023-01-01 17:14 by Bryan1 |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
Looked at that link, $AU17.05 just the PCB. Full kit $AU66.94. Some bad reviews. Searching. In browser type:- site:thebackshed.com searchterms Better results. |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Phil as the link did show a full kit of parts if I only get the pcb I will get the payment reversed as the picture doesn't match the product. Infact I will go ask the question now on aliexpress and done demanding if if it only the pcb stop the transaction or my bank soon will. Infact just went thru the check out again at at no time did it say extra for the parts done and I'll contact my bank in the morning so the hunt is still on. Edited 2023-01-01 18:12 by Bryan1 |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
For all AliExpress stuff you must click on all the icons below the description to make sure what you are buying is what is in the photo. The initial price shown is almost always the cheapest item in the list while the photo is of the most expensive. It is deliberate deception, you only get the real product & price by clicking those icons. |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 458 |
HI Bryan, as far as output power goes from those boards, remember they are like the Powerjacks,( Chinese watts) I have had an 8kw powerjack. There was no way it would put out that much, I rated it as a 2.5 kw at best and 8 kw surge. The current the batteries can supply are a big limiting factor. I don't ever try to run loads that are bigger than about 2kw off my 24 volt system. I added a 500 farad capacitor bank in parallel with my batteries and that made a big difference to the starting current the inverters could supply and also to the time it took to start my compressor. I have a 180 amp mig welder , it runs fine on my inverters. Mostly I am only welding stuff up to 6mm though. It will be interesting to see what you get in the mail. I hope that you get all the parts. If the whole kit is around $66 then buying a ready made board seems a better option. Also many of the boards are slightly different to what the information shows, it can take a while to get the right instructions for adjusting the pots for Low voltage, output voltage and overload. Sometimes the board that arrives does not fit the picture on the site. So some digging in necessary. They are very light on details. Cheers Pete |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Phil I did have a look again this morning and yes in the 4 photos under the main picture it does show the kit of parts. Now looking thru the comments of people that have bought the kit does show and describe the quality of the heatsinks. I looked at my visa debit card account and it cost me $18.10 so at the worst case that is still cheaper than just buying the 8010 board Cheers Bryan |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
G'Day Guy's, While doing some research came across this and solving B came out to 4300 so I just had to go to that link on the last page and the result was the same  Now solving for H it came out to 176.5 A/cm using 10 amps as the current.I worked out the cross sectional area is 83.8cm2 so now armed with these figures off to research a heap more. Cheers Bryan Edited 2023-01-02 12:22 by Bryan1 |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
"click on all the icons below the description " ... and price, on the right. Not the ones under the photo, they are just more of the same thing.  The one highlighted in red is what you have bought. Edit " cross sectional area is 83.8cm2" Puzzled at what measurements you used for that. The width and depth of the centre limb given in previous posts are 58mm and 85mm = 4930 sq mm = 49.3 sq cm. Edited 2023-01-02 17:30 by phil99 |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Thanks Phil I will know next time as I've only shopped once before on ali |
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