Using a large 60hz toroid transformer as an SMPS transformer

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Has anyone here used the toroidal core from a 60hz mains transformer as a really large core for a High Frequency, high power SMPS transformer before???

I figure if you unwrap all the old wire coils from the toroid transformer and get the bare core, then you can wrap your own thick coil wire with the amount of turns you like, as thick of wire as you like, and get a very powerful SMPS because BIG CORES are hard to get for SMPS.

What's your take on this? Has anyone tried this? I'm thinking of getting small 30VA - 500VA toroid transformers, and rewinding them with thicker wire of fewer turns for a high power SMPS core to get well over 1-2KW.

It may prove good for really high power SMPS for insane car audio amplifier for anyone here who likes DIY high wattage!!!

Anyone tried it before? I'm considering getting a small toroid to get a 3,4,5, 6 or more inch toroid core for SMPS.
 
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^^ +1..

for an smps to work properly at HF it needs a ferrite core transformer, then you would have to get into detail what grade of ferrite is good for the frequency you use and so on..

So designing a SMPS is a bit complicated, but then if its car audio you want to use it for, why not use multiple easily available small transformers ?

Say each providing power for 2 channels ?
 
AVE...

Iron core won't work in SMPS design. It will saturate with magnetic field quickly and on the output you won't get much power. It will also get very, very hot. Like a piece of iron in induction heater...

It's better to get ferrite core, even those from old PC PSU's can give you 300-400 watts with no problem. The biggest core I've seen was only twice the size of the core from PSU and the SMPS in which it was used gave out up to 1,3kW...

You must remember that typical switching frequency is 20-150kHz and it's square wave. Iron cores don't like it. However you can build a sine wave generator rated at 50-100Hz and use it with your transformer to form full-bridge SMPS...
 
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If you want to use it at 400Hz or 1kHz or so, you may not even have to rewind it.... most toroids have a pretty good (well, .....) frequency response that should be good enough to improve power transfer and make the power supply smaller.

that reduces the challenge to building a class-D power amplifier with 230Vac output at some kW.... nobody said it was going to be easy.....

just my two cents
 
Well what toroidal cores can be used for transformer cores?
Ive seen gray/white, green, white used as push-pull in amps
Can you use the green/blue cores since they are so common and easy to find?
Can you use red core?
I know yellow/white cores don't make good transformers because they get hot with no load only Good for inductors
 
Well what toroidal cores can be used for transformer cores?

M6 silicon steel laminated. The same material as use in conventional "E-I" power transformers and for the exact same reasons. I've also seen DIY toroids made with the kind of steel strap used to secure loads to wood pallets. I'd say laminate the steel strap with mylar packing tape and roll up a bunch of it. Then wind tightly with tape, maybe even shrink tape, then heat it. That springy steel strap is close to the "right stuff".
 
Has anyone here used the toroidal core from a 60hz mains transformer as a really large core for a High Frequency, high power SMPS transformer before???

I figure if you unwrap all the old wire coils from the toroid transformer and get the bare core, then you can wrap your own thick coil wire with the amount of turns you like, as thick of wire as you like, and get a very powerful SMPS because BIG CORES are hard to get for SMPS.

What's your take on this? Has anyone tried this? I'm thinking of getting small 30VA - 500VA toroid transformers, and rewinding them with thicker wire of fewer turns for a high power SMPS core to get well over 1-2KW.

It may prove good for really high power SMPS for insane car audio amplifier for anyone here who likes DIY high wattage!!!

Anyone tried it before? I'm considering getting a small toroid to get a 3,4,5, 6 or more inch toroid core for SMPS.



IMHO yes, I was thinking of the same thing.
The cores I have are good to over 100khz .
Every time you double the frequency you atleast double the power capablity (or was it 4x).
I found this out as I did a study using them as step-up transformers for ESL's.
And figured out if I used a smps circuit to drive my 200watt core I could get enough power to supply a pair of very large paralleled chipamps at 800watts each just to start with.
But,Yes you would have to rewind them (maybe) in order to handle the increase in current.
But at such higher frequency's it would not require very many turns on the pirmary at all and this makes every thing very easy and simple.

Just do a search on step up transformer design and you should find the thread if not I can find it for you.

jer

Here it is ,

http://www.diyaudio.com/forums/planars-exotics/161485-step-up-transformer-design.html#post2093314
 
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The simple answer is that M6 steel cannot be used in modern SMPS operating at 50 KHz or higher. The losses are just too great.

Thank you. I'm finally glad somebody just gave the simple answer. :D

This is important in DIY, as most DIY'ers are just taking stuff apart or getting parts and trying to find various uses for them, and don't always have the tools or the time to do a bunch of theory and calculating, and just need to know if it's suitable or not for certain projects!:cool:

Gotta keep the steel transformers for the lower frequencies.
 
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AVE...
Thank you. I'm finally glad somebody just gave the simple answer. :D

This is important in DIY, as most DIY'ers are just taking stuff apart or getting parts and trying to find various uses for them, and don't always have the tools or the time to do a bunch of theory and calculating, and just need to know if it's suitable or not for certain projects!:cool:

Gotta keep the steel transformers for the lower frequencies.
You could try SMPS with low frequency around 200-400Hz and sine wave generator driving half-bridge. It should let you increase the max power over the core. I'm not sure of this, but in army we use 400Hz with standard transformers and it works just fine...
 
Thank you. I'm finally glad somebody just gave the simple answer. :D

This is important in DIY, as most DIY'ers are just taking stuff apart or getting parts and trying to find various uses for them, and don't always have the tools or the time to do a bunch of theory and calculating, and just need to know if it's suitable or not for certain projects!:cool:

Gotta keep the steel transformers for the lower frequencies.

The answer was here from Post #2
 
I use a hydro power system of 300 watts that uses a small E-I laminated steel core transformer running at 20kHz fed with 325volt Pulse Width Modulated D.C.
(the turbine generator is actually a 3 phase motor 400 metres away whose output is rectified). The secondary is also rectified to produce nom. 24 volt D.C. Efficiency
seems very good (80% or more) Still, winding a ferrite toroid would be more sensible?
 
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