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If you where able to make your own Transformer what would it look like?

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Chris Cristini

Sat Sept 07 2013, 09:44PM

Registered Member #1749 Joined: Fri Oct 10 2008, 02:04AM
Location: Claremont New Hampshire
Posts: 497

Well as soon as I can get a new camera because my old one pooped out I can show you guys the effect on a little fly back transformer and a copper foil Primary only 5 Turns driven by a TL494 with audio modulation on 12V the arc is a little over 1 1/2" and is so hot it turns the ground pin red instantly it is actually an improvement over my best ZVS Driver at the same voltage and the audio is very loud. I have noticed the IRF510 is no match it latches up fast so I found a CEP50N06 a nice little 50V@60A Mosfet that is much better and last for several minutes before my heat sink is to hot to touch any advice on improving the switching on a TL494 circuit.

My transformer design will defiantly have a wide copper foil Primary when I can get the

time to buy the needed material to build it.

Here is the video of the transformer with the copper foil primary but the CEP50N06 burned up so now I am using a BUZ11 mosfet it works ok but not as good

Sorry about all of the noise in the back ground and the bad video I used my android phone I did not run audio through the driver for the video.

And with the BUZ11 the arc is not as hot as it was with the better mosfet.

Chris Cristini

Sun Sept 15 2013, 06:10PM

Registered Member #1749 Joined: Fri Oct 10 2008, 02:04AM
Location: Claremont New Hampshire
Posts: 497

Turns out the tl494 works better with 12v input voltage than just 5v it switches even the irfp460 with out a problem.

Do you guys think 4 of these would work?

I was hoping my original design to work like this at 12V

Chris Cristini

Mon Sept 23 2013, 09:44PM

Registered Member #1749 Joined: Fri Oct 10 2008, 02:04AM
Location: Claremont New Hampshire
Posts: 497

I am considering a differnt aproach to the primary winding on a new flyback design me and allot of others have made external primarys for ZVS and other drivers I am going to design my flyback with a Robust copper foil internal primary instead the out put on my flyback was minimal compared to the internal primary. Check out this video of the same transformer as the last one but using the internal primary VS the external one I made.

Chris Cristini

Mon Sept 30 2013, 01:17PM

Registered Member #1749 Joined: Fri Oct 10 2008, 02:04AM
Location: Claremont New Hampshire
Posts: 497

Here is another design I made up in a few hours I thought it would be neat to incorporate an oil cooling system with a PC water cooler radiator and a small oil pump and have the ability to change the HV wire so after it gets cooked it can be replaced.

Thomas W

Mon Sept 30 2013, 06:09PM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
Location:
Posts: 1276

Very nice looking!

thing is, anyone can wind a transformer and make a good one at that with some practice... the real problem and issue comes with trying to find a ferrite core sutiable!

Sulaiman

Mon Sept 30 2013, 06:52PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

If I was to make a similar hv transformer I would;
- have two similar sets of windings, primary next to core, secondary on top of primary
. bring out and terminate all four windings, allowing for series/parallel primary/secondary

this way you can have flexibility;
. series/parallel primaries for high/low voltage drive
. series/parallel secondaries for high (balanced) or low voltage, low/high current.

5-0-5 kV is easier to insulate than 0-10 kV and can power a better 'C-W' multiplier.

Chris Cristini

Mon Sept 30 2013, 07:38PM

Registered Member #1749 Joined: Fri Oct 10 2008, 02:04AM
Location: Claremont New Hampshire
Posts: 497

I wish I could figure out how to make transformer windings with solid works it would look allot better. And once again wish I could make the core.

Sulaiman great idea maybe take the first transformer design only with 3 or 4 Secondaries in stead of 7 and collaborate the second design with a better look and with all of the cooling it could be a very reliable transformer. I am also considering a Low voltage ultra high current Design I am considering oil cooling and core cooling any thoughts?

And this seems like a good way to make molds for acrylic.

Ash Small

Tue Oct 01 2013, 11:14AM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

I think your cooling system above misses the point. If you are pushing the ferrite to the limits it will get very hot, and require cooling. You need to submerse the whole Xformer under oil. By all means use directed forced oil cooling in the places that require the most cooling, but you need to cool the whole Xformer.

Chris Cristini

Tue Oct 01 2013, 07:58PM

Registered Member #1749 Joined: Fri Oct 10 2008, 02:04AM
Location: Claremont New Hampshire
Posts: 497

Good point I will reconsider My design maybe an oil cooling sleeve around the ferrite or incorporate channels with in the core for oil flow Most of my design is to look good and also minimize Size and weight while Keeping the ability for several KV and or Current. I want to keep the large oil tank out of the picture with a small Reservoir, A radiator and an oil pump as well maybe oil cooling incorporated to the Semiconductors Heat sink.

Well for making cores I would choose Manganese-zinc ferrite because I don't think we would ever need anything going above 1-200KHz. You can get 10 pounds of Manganese powder for $20 and 5 pounds of Zinc Powder for $30 and not to forget 5 lb of Synthetic Black Iron Oxide for $24 Finding the right formula for these powders is key MnaZn(1-a)Fe2O4.

Ash Small

Tue Oct 01 2013, 08:40PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

I read somewhere recently that you first sinter the 'ferrite', then grind it into a powder with a particle size of ~1 micron, then re-sinter.

I also read that, sometimes at micro-metals, they would need to adfjust the ratios to obtain specified tolerances, but sometimes they could just increase the pressure by 'several tonnes' to get a denser product that met the spec. I understand they are pressed, then fired.

I also read that you 'may' be able to 'fire' them in a microwave oven.

What are you going to use to press the cores before firing?

EDIT: By the way, this is as far as my design has got:

The core has a CSA of 18cm^2, but I'm considering doubling up on the amount of ferrite, to 36cm^2, which will allow me to half the number of turns. See thread here:

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