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Forum Index : Electronics : 6Kw Ozinverter build
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Yep 43 Watts is a good result, I am sure I have had similar results with no caps. Even better no smoke, you could stop at 4 MOSFET in each leg as the HY4008's you are using are a significant upgrade to the orginal 4110s. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Well when all the big caps and fets go on then I'll know for sure what it does. Fingers crossed. BTW that wave looks ok, doesn't it? a bit ripply, but hopefully the caps will help that. Cheers Caveman Mark Off grid eastern Melb |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
That ripple looks like a bit of residual 23Khz PWM switching frequency coming through, its nothing to worry about. The main overall shape looks fine. Some of that ripple can also be introduced by the low sampling rate of your small oscilloscope. I have one of those oscilloscopes, and even a perfectly clean sine wave coming from an oscillator looks a bit noisy,ragged, and bumpy. I have no idea why fitting that larger capacitance dropped the idling current so much, there is some odd effect going on there. Anyhow, so far looking very good indeed. Cheers, Tony. |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Mark, I would use just the four fets until I drove it hard and it survives ( I expect it will). It will do a few kw with just 4 fets total. This way you will prove the circuit is sound before you add all those extra fets. You will be surprised at how it works with just 4 HY4008's. .....oztules Village idiot...or... just another hack out of his depth |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Thanks for the help and feedback fellas. Oz, well, that's an interesting option! Would I need to fit the big caps to run it that way? Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
You can run it without them but the waveform gets a bit triangular if I do that my Midnite charge control starts squawking at me tell me there has been an arc fault. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
I have 4x 20AH 12V in series to test it out currently, if that gets fed with enough amps then I suppose I could run the inverter to that equal level (minus losses) So maybe run a blow heater on level 1, maybe level 2 (2000w)=(48A) I'll need to fit proper wires for DC input to do that, it's currently set up as low current test rig to check operation and wave. Not sure if giving 4 small batteries that hard of a time is a good idea though. Damn, wish I could find a half decent fork battery that wasn't 85% of new price. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
You could run your hair dryer off it  There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Or your curling wand Cheers Caveman Mark Off grid eastern Melb |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Yes, add some caps too, perhaps all of them. Your interested in it's behavior under duress... and replacing 4 fets is very much faster than 16 or more... for the same education. You should get 2kw out of the 4 fets with a decent battery, with the little ones, you can pull a kw for a short time.... thats 20 odd amps. You can try various loads, and the hair drier is a good messy load that will rattle the fets and tranny at low settings. Full speed will be simple resistance, half speed/heat will use a triac making a dogs breakfast of the wave form. If this does not break it, your probably good to go. ........oztules Village idiot...or... just another hack out of his depth |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Excellent, thanks Oz. So after that test, then take the caps back off and test the wave at each addition of 4 fets. Then put the caps back on and give it some real curry. Cheers Caveman Mark Off grid eastern Melb |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
No, if it passes the tests with one fet, I would expect to be fine for all fets. It is no fun putting caps in and out anyway. ....oztules Village idiot...or... just another hack out of his depth |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Unless you use the ones with screw terminals like I did .Too bad they are so expensive, they are a much better quality capacitor though so I got what I paid for... Klaus |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Thanks Oz, I'll assemble the bastard with the final high amp dc cable in the enclosure and see how it runs on one set of mosfets and give it as much curry as I dare. Tinker, I like your idea of mounting the choke, if I cut away enough of the intersecting gap on the aerosharp case a plywood mount can be fitted into that void, and it's in the perfect spot, right between the torroid and the power board. Thanks again fella's Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
OK well since this needs to go in the case next, I started to get that ready. Covers trimmed to fit in the middle, I'll get a rubber trim strip to fill the gap in the middle. Has anyone got any bright ideas how to conceal/use the cutouts for the old LCD displays?  Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
A power point is a good fit for those holes, maybe the other one could be used if you are planning to add a LCD CRO screen permanently. I found once you have confirmed everything fits okay it is probably easier to assemble it where it is going to live. But first you need to get the electronics finished and tested. I know Tinker would assemble everything and then test it but I am not that game. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
My old PJ conversion inverter was fitted into one of these Aerosharp boxes. I found it a pain to fit anything to the lid (which I did) as the wires have to be long enough and movable to remove that lid. I ended up using special marine offset hinges to take care of the lid but still had the moving wires when opening it. Yes, you *will* open it a few times while in the testing (for cooling) stage. But, if you mount sockets/ switches etc on a secondary panel so they poke thru that opening in the lid, everything remains in place when you take the lid off. Have a look at the pictures on the last pages of my inverter build. I made the whole enclosure but the controls poking thru panel cutouts principle was the same. I am just in the process of connecting the control panel of my latest inverter. It should be finished soon and if it works I'll post more pics on this forum. Klaus |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
"If it works" C'mon you're German, don't speak like that! Cheers Caveman Mark Off grid eastern Melb |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
No Mark, while I can speak German, I'm Austrailan. Been here 50 years this year. I was just thinking about what time it took to get the previous inverter running. This one is identical but for a single core toroid. Klaus |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
I like that idea. BTW guys Ali exp have an anniversary sale on, I just got another 100 mosfets. here Cheers Caveman Mark Off grid eastern Melb |
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