Author Topic: Building a 6kw pure sine wave inverter using power jack boards part1 transformer  (Read 120216 times)

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bcalmed

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never mind
« Last Edit: April 29, 2016, 05:04:06 PM by bcalmed »

joestue

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one of those, 2kw rated.. 53 pounds for 110$ after shipping.
that's a really good deal considering the core will cost you 3.30 usd/lb plus shipping at alphacoresdirect, and copper is 7-9 dollars a pound for new magnet wire.

the other, 2500 va, the 240/153 one.. also a very good deal, better than the other.

not sure about the triad, no information. does not look very large.

you may be able to find the midpoint of the 240 winding, snip the wire, then parallel them for 120 vac.
there should be enough copper from the 153 volt winding to rewind for a 13 vac winding.. whatever you need to make the inverter happy with the turns ratio.
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

bcalmed

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never mind...
« Last Edit: April 29, 2016, 05:05:13 PM by bcalmed »

bcalmed

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Heck, I just bought the monster. The dern thing is 14" in diameter!

http://www.ebay.com/itm/NEW-2-0KVA-2000VA-230V-to-115V-17-39A-Step-Down-Toroidal-Power-Transformer-/281542186688?hash=item418d38d6c0:g:8Y4AAOSwc3ZUnc-C

I'll let you know how it's wired when I get it.

He's got 20 odd more, so...
« Last Edit: April 29, 2016, 03:43:07 PM by bcalmed »

oztules

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It is dirt cheap... beautiful.

Strongly advise getting two at this price, as it gives you a huge range of options then.

I would strip both, pull out some of the core to get a bigger center hole to work with, and go from there... make a good 5kw or more transformer with both cores.
Hole size is important for getting the primary in there, and doubling cores brings a 25% reduction in copper length no matter what you wind.... try for a 4" core hole ( bare).

Strange they are only running 17A@110v...  conservative rating for a 24kg unit.


.............oztules
Flinders Island Australia

bcalmed

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Strange they are only running 17A@110v...  conservative rating for a 24kg unit.

Yeah, I thought so, too.

The hole, BTW, even with the existing windings, is ~3.75".

I'm going to check this beast out when I get it - I'd really rather not strip it.

oztules

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....... nice hole size then... all good.


..............oztules
Flinders Island Australia

bcalmed

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OK, after life intruded, I spent some hours yesterday stripping the outer (secondary?) layer of the toroid. It was ~13AWG, four in hand.

What fun...

Then I pulled off about a bushel of mylar and found that the lead marked "screen" was a layer of copper tape encased in plastic. I think this was for some audio reason.

Finally, I excavated the ends of the primary and it's ~13AWG two in hand. I'm not sure what that translates into in mm or mm2, but I figure since I really only need 2500W, maybe that's enough.

At this point, I'm reluctant to keep going and wonder if there's some way to figure out how many turns are (neatly) wrapped already and work backward to a number for primary turns.

I'm doing this mostly just for fun but I imagine I would want it set up for 24vdc to 120vac.

 
« Last Edit: July 11, 2016, 02:35:03 PM by bcalmed »

oztules

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If  thats the 240v winding.

1.Apply 10 turns of wire to it, to act as your test secondary.

2. apply 240v to the winding, and measure the voltage in the 10 turns

V/10 will get you the turns per volt..

From that you can know how many turns you will need for your primary.... or how many turns are on there for the 240v winding.... and take off what you then need for 110v.

For the PJ boards, you will want 15v primary, and for the eg8010 design I am running now, then 13v primary.

..........oztules
« Last Edit: July 11, 2016, 04:57:52 PM by oztules »
Flinders Island Australia

bcalmed

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Forgive me for being dim, but can I use 120v to apply to the primary since that's all I've got? then it's still turns per volt?

And I seem to recall the light bulb thing about popping breakers....

....in series to start and then short across the bulb, right?

bcalmed

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Did that w/120v and got 6.4v on the 10 turns - so 20 turns +/- for the 13v primary?

I've got ED - Electronical Dysfunction - sorry

-Rick

Mary B

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Maybe wind 21 turns to compensate for load losses... then test it again. You can wind that with just some scrap to test.

oztules

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What are you actually building.
Are you using the pj boards , or the egs002 boards or the ed8010 boards that I now use.

They have different dynamics depending which type you go with.
The 13v figure came from where... or is the the system voltage your going with... advise against that for the power you look to be chasing with that core... better to go 48v.

For PJ thats a 30v primary, and for the 8010based chips, 26v... proportionally down for lower voltages.

..........oztules
Flinders Island Australia

bcalmed

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Maybe wind 21 turns to compensate for load losses... then test it again. You can wind that with just some scrap to test.

Hi Mary,

21 it is - 13.2v!

Thanks!

bcalmed

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What are you actually building.
Are you using the pj boards , or the egs002 boards or the ed8010 boards that I now use.

They have different dynamics depending which type you go with.
The 13v figure came from where... or is the the system voltage your going with... advise against that for the power you look to be chasing with that core... better to go 48v.

For PJ thats a 30v primary, and for the 8010based chips, 26v... proportionally down for lower voltages.

..........oztules

I would probably use this just for 1 or 2 camping trips a year - it's not meant to be anything other than an exercise to see if I can build one.
Hence the 24v - I've got 2 batteries and a couple of 12v 135W solar panels I usually take camping anyway.
Doubt if I'll ever exceed 1 kw and that just for the coffeemaker for a few minutes.
Anyway, in case it's not obvious, I pretty much don't know what I'm doing, but I'm gonna do it anyway.
I think I'll use the egs002 chip so the 13.2 should be good - I hope!

-Rick

joestue

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far as i know the exact voltage doesn't really matter, but the 13 vac allows for a 10% voltage drop in the transformer when running off of a 20 volt (ie, completely dead) battery.


if you never intend to run your batteries below 12 volts, and if you have a lower voltage drop in the transformer then you can run a lower turns ratio transformer, and the system will be more efficient due to lower losses in the inverter.


It would be nice if you can find the midpoint of that 240v primary winding, snip the wires and wire it for 120v. but that may be difficult to do. however if you only need 1 KW from this transformer, then you don't have to do that.. it will just be about 90% efficient rather than 97.5%
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

bcalmed

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another dumb question - when you guys refer to ?mm wire, is that diameter or cross sectional area?

oztules

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I always mean cross section in mmsq.... diameter is ambiguous, as multi strand may have a lot of air gap that contributes nothing to lowering  the resistance per 1000 meters./feet etc.


............oztules
Flinders Island Australia

bcalmed

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OK, so the 13 AWG on my toroid is 2.63 mm2. I assume that's better for copper loss in the "secondary"?

oztules

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More is always better :)

........oztules
Flinders Island Australia

bcalmed

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So, assuming I DID somehow manage to find the center point on the original primary (240v), would I then parallel the two "halves" of the ~190 turns? and is there a certain way to do it - like is there a phase thing involved?

Or am I stuck with the unwind/rewind slog? And, if so, then should I wind on, maybe, 3 layers of ~114 turns or even 2 layers of 114 turns 2 in hand?

I'm in it this far and the copper is there...


joestue

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Parallel the two halves of what would be 95 turns each..and they need to be going the same direction.

I don't really see the point of reducing the volts per hz. usually the iron loss is very low, and reducing it just a little bit more only increases copper loss.

however leakage inductance follows turns squared, so more turns equals less current ripple. what are you using for an inductor on this machine?


since you only intend for a kilowatt or so, two wires is enough copper. (for a 120v secondary, 1KW = 8.3 amps)
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

influence

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Hi all I have been following these powerjack build threads on anotherpower and here on fieldlines with the great coaching of oztules. The man with the good oil :)

Well I have started a build of a decent 10kW version....using 15kW boards from PJ. They now have a new control board with Version 3.5A. It appears to have some changes esp to the LC filter of the output stage.

More importantly I asked a manufacturer in China recently to build me a core that we can use / stack to wind to our own purposes.

The core specs are:

- OD 230mm
- ID 100mm
- Height 105mm
- Core weight 27kg
- Core material HiB - High Permeability CRGO steel. Cold Rolled Grain Oriented Steel.
- Designed for optimal operation at 50/60Hz.
- Core cross section is 105 x 65mm

You can stack 2 and get a 210mm core...or 3 to get 315mm high core...

The good news is they are willing to sell on Aliexpress.

https://www.aliexpress.com/item/transformer-core-230x100x105mm/32722481590.html

You can negotiate some better freight. I had mine sent by the slow boat but I ordered 3 cores....

These cores are well over the 2800sqm rule of thumb that oztules has come up with.

Cheers
radiantinfluence

influence

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Btw my 3 core specs for 230V - 48V system.

Core overall cross section is 65*315 = 20475 mm2.

Using oztule's magical turn conversion factor for PJ boards,

2800sqmmm is used for 1 V / turn.

So my triple core will get me 20475/2800 = 7.3125 Volts / turn.
 
Primary will be 100sqmm AC cable

30V needs 30/7.3125 = 4 turns approximately.

Secondary will be 35mm2 AC cable

230V needs 230/7.3125 = 32 turns approximately.

Maintainting the 8:1 ratio for PJ boards setup.....

Its going to suck winding this as the core alone will weigh 81kg....

oztules

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Simply massive..... huge.....mmmonster.

They certainly are cheap cores, and the freight is ..... well a ship is the only economical way I suspect.... keep us in the loop too.


............oztules
Flinders Island Australia

DamonHD

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@influence Can you please confirm that you get no reward from sale of these cores so that we can consider waiving our "no commercial links before 50 posts" rule?

Rgds

Damon
Podcast: https://www.earth.org.uk/SECTION_podcast.html

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influence

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Sure thing Damon I can confirm that I got nothing to do with that store nor do I get kickbacks. The aliexpress listing was actually put there a few days ago for purchasing online. I actually contacted the manufacturer through Alibaba....a few days of collaboration looking for the right core material and bam they wound a few...

I just did this to help out those that want to build their own monsters....

influence

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I also have another core coming from another manufacturer, its a SINGLE OD 230 x ID 100 x H210mm core...it weighs 52kg...the material for that is also HiB CRGO steel...

Once I receive it I will take photos and post.

influence

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Btw here are some pics of the V3.5A Control Board...


Bruce S

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DamonHD;
Sorry late seeing this! Massive GIS update that Ain't going well :-(.
I can confirm also that Aliexpress is known to me, I've purchased LED track bulbs from them along with various other items.

Bruce S

 
A kind word often goes unsaid BUT never goes unheard

oztules

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Thanks Influence,

That board looks essentially the same, except they have put the meter board and transformer on the card, and a resistor staircase for the changeover... maybe they have solved the ups problem.

Your building some serious sized stuff there

Bruce, I have gotten a load of stuff from Aliexpress..... mostly good... some fets below par, but mostly good.


..........oztules

Flinders Island Australia

frackers

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Bruce, I have gotten a load of stuff from Aliexpress..... mostly good... some fets below par, but mostly good.

I've had the same results as Oztules - I even have an account with them.

Everything I have ordered over the last 3 years has turned up, everything worked on arrival but like anything commercial, you get what you pay for!!
Robin Down Under (Or Are You Up Over)

clockmanFRA

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I tried to get a UK firm to cut and send anywhere in the World the 3 Heatsinks for the 6kW-15kW OzInverter Power Board.
But sadly they decided to charge silly money.

At least the Chinese see a business opportunity and are willing to stock and sell a particular size of Core. However, like most things there seems to be a middle man acting as the agent and can promise everything, (personal experience). So I await to see the pics of the Silicone Iron cores.

My core winder/maker in the UK can only wind up to 60mm thick, that's the max his machine will take.

My 6kW OzInverter is happy with a 28kg core, my big OzInverter has a 36kg core. Its handling the 36kg core that problems arise, like Damaging the secondary enamel when winding, lifting and moving, optimising the cut out on the core support table so you can physically get your fingers underneath and lift and turn safely.

Yea 36kg is my safe physical manipulation max. As Oz once said, "You will need a crane to wind that". I didn't but it was close.

I look forward to watching this huge build.
Everything is possible, just give me time.

OzInverter man. Normandy France.
http://www.bryanhorology.com/renewable-energy-creation.php

3 Hugh P's 3.7m Wind T's (12 years) .. 5kW PV on 3 Trackers, (8 yrs) .. 9kW PV AC coupled to OzInverter MINI Grid, back charging AC Coupling to 48v 1300ah battery