custom flyback!!! Where to buy? Please help! / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

custom flyback!!! Where to buy? Please help!

1 2 next

Move Thread

LAN_403

baleworker

Fri Jul 18 2008, 08:54PM

Registered Member #1596 Joined: Fri Jul 18 2008, 08:43PM
Location: USA
Posts: 65

Hello everybody!

I am looking for a powerful 500-1500W flybacks, at least twice the size of a regular TV ones.

Does anyone know where to get them? Or any place who can make one for me?
Thought of winding it myself but could not even find any flyback parts, like bobbins or ferrite cores. Also there is no design info on high voltage flybacks.

I have a sample transformer taken out of an Asian laser power supply and need something similar but with different step up ratio, somebody must be selling them!

Output should provide 10-12kV DC at no load, 150ma max load current

Please help!!!

...

Fri Jul 18 2008, 10:41PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Getting a ferrite core good for 1.5kw is easy, but insulating it to be able to stand up to 10+kv won't be.

I wound one a few years back, that was good for a KW or two (see second post). But I had major corona between the primary/secondary (not even 1/8" of plastic would stop it) and my primary was not happy with all of the reactive power associated with a mazzilli flyback driver. If you used a core with a larger window it should be possible to solve both of those problems.

I would offer to wind you some, but I just lacerated the crap out of my thumb so I am going to be out of the coil winding business for a few weeks

baleworker

Sat Jul 19 2008, 12:15AM

Registered Member #1596 Joined: Fri Jul 18 2008, 08:43PM
Location: USA
Posts: 65

Thanks tons!

I almost lost hope, many profs were telling me its beyond their process capabilities. Now I am back on the road.
Speaking of a Chinese PS I have, it outputs 24kV at 30mA. Over 700W !!! The diode or voltage doubler is integrated into the transformer.
I found the core they use:

it is UYF18A. Everything is enclosed into a nice plastic molding. No arcing/corona. I wish I could find the molding and bobbin as well. Then I could experiment with wounding. As you can see the core is very small, I cant believe they could insulate it up to 25KV!

Attached is the pic of the transformer I have.
Anyone knows where I can get those bobbins/enclosures? Any good websites on flyback construction/design techniques? Do you guys use machines to wound them?
I am fairly new to it and dont wanna step on the mines.

Thanks again,
Any input is highly appreciated!

Andyman

Sat Jul 19 2008, 01:52AM

Registered Member #1083 Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256

The "enclosure" is mostly potting. After the coil is wound, they are potted in epoxy. Of course what you see is the plastic casing that the potting was poured into, but I doubt you can purchase those.
To get a suitable bobbin, just find some plastic tube that fits over the core and wind on that. Or get a sheet of plastic and wrap it around the core and tape it to the right diameter. Take it off and then start winding.

Arcstarter

Sat Jul 19 2008, 05:01AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

You can make your own with about 100 turn secondary and about 5-10 turn primary. Just get the core of a flyback transformer(the bigger,the better) and get either a piece of pvc pipe that fits securely over the core or what i did was got a $1 thing of polymer clay and put it over the core. I then baked it to make it hard in a stove at 200 something degrees for 20 minutes. I wound one layer of 28 gauge wire and used my 555 flyback driver at 50 volts and it would give out pretty high current at what looked like my 6kv nst's voltage. You could get some transparencies and wrap some around that first layer and then wind another layer, or maybe even more. Idk how it works so well, i guess by inductive action. I ran it at a little bit above audible freq.

Dr. Dark Current

Sat Jul 19 2008, 07:25AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

You can wind one yourself, it is easy. You should keep at least 2kV/mm air insulation everywhere (so if your output is 10kV, you need to make at least 5mm gap between secondary and core/primary) And if you have problems you can always put it in oil.
I wound a transformer on a regular flyback core which did output ~20-30kV without large corona problems, you can use transparent sheets as interwinding insulation and use around 50 turns per layer.

HV Enthusiast

Sat Jul 19 2008, 01:07PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Contact D.C. Cox at Resonance Research. (Just go to website)

He has lots of these he sells for $25.00 each.

Dr. Dark Current

Sat Jul 19 2008, 01:37PM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Dr. GigaVolt wrote ...

Contact D.C. Cox at Resonance Research. (Just go to website)

He has lots of these he sells for $25.00 each.

$25 that is pretty cheap, I would get one but i guess shipping to europe would be just as much...
Do you know how much kW (

) can they take?

HV Enthusiast

Sat Jul 19 2008, 09:46PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Actually, its $45.00, not $25.00. Anyways, here are the specs. This was from awhile ago, so i'm not sure if he still has them available, but i'm guessing he does.

The large flyback transformers have the following specs:
Overall dimensions: 5 in. x 3.5 in.
Sec. coil: 2.375 in. dia.
16 turn primary c.t. with 16 AWG wire
Special HF RF core material with 5/8 in. x 1/2 in. cross section of core
Unit operates very smooth at 120 watts continuous and up to 300 w. for short
duty cycles
Rectified 32 kV DC output and over 60 kV with doubler circuit
Units available for $45 and $6.85 for s/h

wrote ...

I am looking for a powerful 500-1500W flybacks, at least twice the size of a regular TV ones.

BTW, a regulator TV flyback puts out very little power - about 15W typically. A 500W to 1500W flyback transformer would be absolutely huge, probably about 100 times the size of a regular TV flyback. You're not going to find anything like that off the shelf.

Dr. Dark Current

Sun Jul 20 2008, 04:03PM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Dr. GigaVolt wrote ...

BTW, a regulator TV flyback puts out very little power - about 15W typically. A 500W to 1500W flyback transformer would be absolutely huge, probably about 100 times the size of a regular TV flyback. You're not going to find anything like that off the shelf.

Not really, most will run at least 150W continuously, the older "bare wire" ones are often happy with 200 watts or more. I ran one modern potted flyback at 600 watts, it was smoking hot after 20 seconds but it survived

(the ark was 20cm long)

To OP: you could get 10 similar units (check ebay etc.) for 1.5kW of power into an arc (remember thats much more reactive power).

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob