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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 08:35pm 21 Jan 2018
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It is important to realize what you are trying to achieve. No point in going for low idle, if your driving it hard a lot of the time. Heat and losses in the wire are a result.
You want compromise between idle and power, not one or the other.
If your cross section calculations are for 114, then 136turns is over the top, but suits your hole size.
It needs to be redistributed so it is even or you will get some leakage... thats why I said to have reference points around the core to see how you were doing.
You have a few more layers to do, and the real estate gets eaten away each time... so you will need that "gap" distance so as to accommodate the last payer in a co-planer fashion.
If you go to 150turns, you will not have neat windings in the next two layers, and ruin the 1 layer winding idea.....you will have high differentials across the wire enamels as you over wind to accommodate any more wire.
Plus your losses driving any load will increase by 25% because of the extra wire there.
These are powerful inverters, and so idling power is not that important, as when using a small inverter on limited battery supply. I expect that this will have 500-1000AH@ 48v.... so if you get the thing running with less than 50 watts or so, it is no big deal at all..... and 114 turns would have delivered that I expect.
If you have to worry about 1kwh/day, you have little to worry about.
..........oztules
Edited by oztules 2018-01-23Village idiot...or... just another hack out of his depth
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 09:08pm 21 Jan 2018
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Thanks guys, Oz, yeah I was on track to get to 150, there are texta marks at each 1/8th. Looks like the 150 was getting a bit greedy. Just tried to slide them around with a mix of dishwashing soap to make it slippery enough (just a bit, didn't soak it) The windings do come around but it now makes them loose and it will be impossible to get them even, the enamel could be getting damaged underneath too, no way to tell. There appears to be plenty of wire from the two 3kw coils unwound, so I'll unwind this and put it aside and start again. I would rather it was nice and tight and evenly spaced.
Cheers MarkCheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 09:30pm 21 Jan 2018
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For doing tests like this you could use insulated wire and wind it on for a temporary test.
Just adding to what Oz said, if you half the core loss it is only going to make a >20W difference, that's under 500 watt-hours per day. Even then during daylight it won't matter at all so 2/3 of say 450 leaves 300 watt-hours. There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 09:46pm 21 Jan 2018
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Yes when you compare it to an 800ah bank it's not a lot. It wasn't anywhere near as hard to wind as most people claim, my hands are pretty strong as I use them strenuously all day. No big deal.Cheers Caveman Mark Off grid eastern Melb
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 05:32am 22 Jan 2018
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How does this look Oz? Core is split up into 8 sections, if I do 16 per section it ends up with 128.
BTW I looked everywhere for a good spool to use, buggerings had some ones that rope came on, but they broke first use. Ended up using Rouge fishing gear spool $10 from BCF, just tossed the line. Anyway it fits perfectly, will need to trim down the sides on the next two passes though as it's snug already.Cheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 07:22am 22 Jan 2018
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That looks good Mark.
I have seen the spool I use at Mitre 10.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 07:36am 22 Jan 2018
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The BCf "rouge fishing line" spool is really solid, should last three or four builds, will need a trim though. Anyone in eastern Melb wants 128m of 60lb fishing line I have it wrapped around a tonic bottle, might take it to a pier next time I pass one, hate seeing things go to waste.Cheers Caveman Mark Off grid eastern Melb
Ralph2k6 Senior Member Joined: 24/09/2017 Location: AustraliaPosts: 129
Posted: 08:17am 22 Jan 2018
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Bicycle rim with slot would be ideal here, right?Ralph
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 08:52am 22 Jan 2018
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Small spool in photo above works best IMHO, I tried bike rim and found it to be a PITA.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 09:42am 22 Jan 2018
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Well I did a layer in 5 hours with plenty of breaks including dinner, prob 1 hr non stop would do it, but you're better off having breaks. Having a solid spool you can pull on hard really helps. It's really not hard at all, just tedious and fiddly. Epoxy when it warms up in the morning and add the mylar. Cheers Caveman Mark Off grid eastern Melb
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 09:46am 22 Jan 2018
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BTW I loaded the spool by using a big drill bit and wound lots of tape onto it till there was a snug fit in the small spools centre, use a cordless drill and BAM all done in a matter of a min, thanks Madness for that idea.Cheers Caveman Mark Off grid eastern Melb
Ralph2k6 Senior Member Joined: 24/09/2017 Location: AustraliaPosts: 129
Posted: 09:59am 22 Jan 2018
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Looks bewdifulRalph
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 11:00am 22 Jan 2018
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The next layer is probably easier as you don't need to worry about the spacing.
Take your time with the phase and turn checks, join together the 2 ends where you start your winding and connect to Neutral. Volts must be exactly the same N to A and N to free end of last winding and 0 volts between active and the free end.
If there is 1 volt difference something is wrong with the number of turns, if this is the case you have to work out what it is. When you get to the end of the next wire leave a metre or so extra while you do the tests in case you need to put any more turns on. Once you have confirmed it is correct the cut it to the final length. Don't forget you are working with live AC power also.There are only 10 types of people in the world: those who understand binary, and those who don't.
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 12:01pm 22 Jan 2018
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Mad, on a two stack its more likely 2V/turn so a missed/added turn is easy to spot with AC volt measurement.
Another test I did was to check for shorted turns at *each* stage, easier to just unwind the last, not yet epoxied layer if a fault was found. I measured the current for one winding and wrote that down. Then I placed a bit of wire once through the hole and shorted the ends. The current in the completed winding changed markedly and I wrote that down too.
Now I had reference currents to compare each subsequent winding.
BTW, some strange ideas like using diswash liquid to slide the windings around might be regretted later if the idea was to epoxy *each* layer after it was tested. Epoxy requires a clean surface to adhere to. It is used is to lock the turns together, especially inside the hole, and to provide extra insulation for these unavoidable micro cracks in the enamel from recycled wire.Klaus
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 01:03pm 22 Jan 2018
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plus there is quite often salt in dish liquid as well. I'm confused, no wait... maybe I'm not...
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 08:07pm 22 Jan 2018
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Thanks for the replies, I replaced that wire as it would have been too work hardened to straighten out again and reuse it so I just used some fresh wire as there was plenty of it.Cheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 08:44pm 22 Jan 2018
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Klaus he has more turns on there than normal so the voltage would be a little lower, my point though is any difference means there is an issue.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 05:45am 24 Jan 2018
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Hey guys I'm still ordering bits, need the resistors for the power board some are 5.6ohm .6w and some are 2w. Can I just use the 2w for all of them?
Also what is the % number that they have mean?
Cheers Mark Cheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 06:10am 24 Jan 2018
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The 2W ones won't fit properly where the others go, 1/2W resistors cost $1.50 per hundred delivered on Aliexpress. I don't know where you can get 0.6W, just get 0.5W.
Tolerance % how close is the actual value to what is supposed to be.Edited by Madness 2018-01-25There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 06:13am 24 Jan 2018
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Thanks Madness, you've been a big help.Cheers Caveman Mark Off grid eastern Melb
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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