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Forum Index : Electronics : Summary / list of members' inverter projects?

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Warpspeed
Guru

Joined: 09/08/2007
Location: Australia
Posts: 4406
Posted: 05:45am 18 May 2021
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  flyingfishfinger said  
From what I gather, this is not something I would get OTS - I should wind this on a suitable toroid myself right? Will start a thread for my build shortly.

R

Highly unlikely direct off the shelf. 16v at around 188 amps would be a pretty unusual application, even for a really large 12v battery charger.

Almost always the low voltage winding goes over the top of the higher voltage winding, so a 3Kw transformer, 110v to XXX volts may be pretty easy to rewind just the lower voltage outer winding.

Transformers of that high a power rating may more usually be 220v. But you may find one with two 110 primary windings.

Are you feeling lucky ?  Something will turn up if you are both persistent and patient.
Cheers,  Tony.
 
InPhase

Senior Member

Joined: 15/12/2020
Location: United States
Posts: 178
Posted: 06:03am 18 May 2021
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EI type auto transformers used for buck-boost applications are readily available in the US with 240/120:32/16 ratio as big as you like. Basically two transformers in one box, configurable externally for 120 or 240 input and 16 or 32 volt output. Used in reverse, this could provide the 120/240 VAC split phase if you wanted.

Bought new they are pretty pricey. Here's one from eBay: https://www.ebay.com/p/3012452604

Keep in mind that the kVA rating on the plate is it's rating when being used as an autotransformer. Using it as a step up isolation transformer will reduce its rating.

Toroids are better, but better is relative to how much you want to have to put into this project.
Edited 2021-05-18 16:05 by InPhase
 
BenandAmber
Guru

Joined: 16/02/2019
Location: United States
Posts: 961
Posted: 07:10pm 18 May 2021
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Check out the size wire so used in those type trannys

  I have seen a 14 gauge wire in a similar Transformer used for 7500 watts

The ones I have looked at are horrible for a inverter

What size are you looking for

If I remember correctly you have one that will do around 3000 watts

3000 watts is enough for most of the people on here that is off grid

3000 watts continuous can do short bursts of a lot higher wattage

So the first thing in my opinion is to figure out how many normal and Peak watts you will be using

There is 2500 watt toridal trannys on ebay for was 99 now 120 including shipping

I have been told that these Transformers will do 4 or 5,000 watts when more copper is added

Two of those stacked up and wound as one would make a Transformer that would do some pretty crazy high-wattage

And I bet the guy would take $100 a piece like he was asking before for them if you bought two that's
including  shipping

The wire already on them could be reused both the low and high side for the new high side

Then add a new low side using battery cable wire or welding lead wire

For under 300 bucks and a little hard work you will have WELL OVER a thousand dollar Transformer

Let me know if you need the Ebay link
be warned i am good parrot but Dumber than a box of rocks
 
BenandAmber
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Joined: 16/02/2019
Location: United States
Posts: 961
Posted: 07:19pm 18 May 2021
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be warned i am good parrot but Dumber than a box of rocks
 
BenandAmber
Guru

Joined: 16/02/2019
Location: United States
Posts: 961
Posted: 07:38pm 18 May 2021
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I talked to this guy a few months ago maybe it's been longer than that now but he's got a bunch of these Transformers

Very reasonable guy and he sold a lot of them for $99 including shipping

He knows how to rewire Transformers and he said that these would do 4 or 5000 Watts when rewired

I have wound and tested many trannys

It's all about heat!!

How long are you going to be running at higher wattage

You can add more copper to a smaller core and get alot higher watts from a smaller core

You can double wattage of a core as long as it doesn't have time to heat up or you have a way to cool it  

Oil is the very best way to cool a tranny

Oil is a excellent insulator that also please don't bash on me stores dielectric

It has a GREAT relationship with a Transformer

I think boost buck is the search will get that style Industrial Transformers

But I do think they will be very high idle  and small wire for the rated wattage

If a person couldn't find toridal cores you could make your own

There are a few videos on YouTube of people making Mainely audio troidl Transformer from scratch

These people will answer you back if you text them to tell you the type of metal they use and the Heat Treating process

In my opinion the cheapest route to go is to buy used Transformers

Enameled wire gets really expensive along with the cost of the core

I always get my Munch Cheaper by buying a used Transformer and reusing The Wire already on it

The jackpot is when you find a isolation Transformer both the input and output is same voltage

With these type you can use both input and output winding as your new high side and just as a new low side

It makes the job very easy with very little work when you don't have to redo the high side and only have to wind a new low side

Anyone reading please refer to the experts  I am just a dummy that likes to experiment
Edited 2021-05-19 06:10 by BenandAmber
be warned i am good parrot but Dumber than a box of rocks
 
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