Author Topic: Building a 6kw pure sine wave inverter using power jack boards part1 transformer  (Read 81843 times)

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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%

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)

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

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.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

Mary B

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Good source for heatsinks in the USA http://www.heatsinkusa.com/ I have used them on a couple ham radio amplifier builds.

influence

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No issues with aliexpress....For bulk parts they are definitely cheaper esp since they can list things for less than a dollar (compared to ebay)...
Ive had a couple of packages lost. It was fully refunded/resent

Stick to sellers that can offer e-EMS, DPEX,OPX Singapore and e-Packet. Some of the fastest (relative to cost) freight methods compared to chinapost...

Aliexpress is managed and funded by Alibaba which is a mammoth company compared to Ebay...

I trust their resolution process. Basically you put in a dispute, submit evidence. If the seller is being less than forthcoming you escalate the dispute
and aliexpress steps in. I have only had to use that method when I get fake ICs and mosfets or something is broken on delivery.

...annoying but I get refunds each time.

influence

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Btw oztules you are right about the board mods...I believe the ports J2 J3 L1 can be used to monitor the mains output...great if you are building your own monitoring system.

Neil

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 influence,

I noticed that your control board has no low cut off resistor on it, did you have to put one in or does it work find
with out it?


Neil

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Hi Oztules,

I know you don't use the power jack boards anymore but was wondering if you could help me out. I ordered a control card last year for a 48v inverter, it was supposed to be 60 hz but they sent me a 50hz card, do you know what cap needs to come out or replaced in order to get the 60hz?
The control cards are like the ones in message #193.

Thanks,

oztules

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Not a clue... I would expect it is in the software. In the 8010 boards it is pin selectable.

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

Neil

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thanks Oztules.

was afraid of that.