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Help wiring a flyback transformer.

LaZeRz

LaZeRz

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Hey guys! I recently took apart a CRT and got a nice little flyback out of it :)

DSC07845.jpg


I think im going to go with a ZVS driver for efficiency and im also going to have to find a rectifier for better arcs :)

But, for starters, I need to know what the inputs and outputs are! I'm positive that the suction cup that sticks onto the side of the tube is positive (pun intended) and im guessing the H-OUT on the bottom of the PCB is negative?

DSC07846.jpg


Also, about winding magnetic wire around the primary and secondary coils, How exactly do I do this? Also, do any of you's have a link to some magnetic wire?

Thanks!
 





Get that sucker off the board so we can see what your primary looks like, and I'm sure this can work for you. Is an old old old crt?
 
Since you said you are using a ZVS for this, that circuit is just a push-pull oscillator, so you will need a primary with a center tap (average of 10 turns with a center tap from my past experience). Magnet wire is not nessasary, you can use multi-stranded pvc/silicone wire (14gauge-18gauge) (easier to wind then solid magnet wire at those gauge sizes, and still handles the current nicely).

I pretty much never use the original potted primary of the flyback, it often can't handle being driven to any respectable power, instead, wind some turns on the "arm" of the flyback (the exposed ferrite arm you see behind the potted winding).

Another trick I use to find the other end of the secondary, is once powering it up with the newly wound primary, you can just quickly run the suction cup (half-wave rectified, positive for that modern flyback like yours) across the base, it will become quickly apparent whats ground, as you will pull a big arc from it.

If you ever find an older flyback, ones with a disc shaped winding and a open core, those don't have any internal cascades or diodes, (usually they feed an external multiplier elsewhere in the TV) so the output will be AC.. these "newer" plastic and epoxy potted flybacks are always half-wave rectified (they still push out anywhere from 20kv to 50kv)

Thats pretty much the simplest way to go on about it.
 
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Unfortunately, I know that style of flyback that you have there... I have an identical one. It's no good. I've tried it :\
 
It just doesn't draw large arcs. The one I grabbed is literally identical to that one, and, compared to the yellowish-white potted flyback, it barely draws at all. While on my other flyback I can get an arc started at 1-1.5cm, I have to go in to like 2mm on that flyback.
 
GBD said:
Since you said you are using a ZVS for this, that circuit is just a push-pull oscillator, so you will need a primary with a center tap (average of 10 turns with a center tap from my past experience). Magnet wire is not nessasary, you can use multi-stranded pvc/silicone wire (14gauge-18gauge) (easier to wind then solid magnet wire at those gauge sizes, and still handles the current nicely).

I pretty much never use the original potted primary of the flyback, it often can't handle being driven to any respectable power, instead, wind some turns on the "arm" of the flyback (the exposed ferrite arm you see behind the potted winding).

Another trick I use to find the other end of the secondary, is once powering it up with the newly wound primary, you can just quickly run the suction cup (half-wave rectified, positive for that modern flyback like yours) across the base, it will become quickly apparent whats ground, as you will pull a big arc from it.

If you ever find an older flyback, ones with a disc shaped winding and a open core, those don't have any internal cascades or diodes, (usually they feed an external multiplier elsewhere in the TV) so the output will be AC.. these "newer" plastic and epoxy potted flybacks are always half-wave rectified (they still push out anywhere from 20kv to 50kv)
Thats pretty much the simplest way to go on about it.
Click to expand...

Sound advice.

The old ones, you can just rip out the primary and put a few turns of insulated wire in yourself, connected to the driver and boy those things go nuts!.

Also, over driving a car ignition coil can yield satisfying results :p
 
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The CRT I pulled this out of is veryyyy old. The whole board was covered in dust when I removed it :p
 
LaZeRz said:
The CRT I pulled this out of is veryyyy old. The whole board was covered in dust when I removed it :p
Click to expand...

Belive me, that CRT is definatly NOT old in comparison of whats out there.
 
haha fail.

Now go open up tha humungo CRT TV in your backyard! you know? the one you are scared of! :D
 
Fiddy said:
haha fail.

Now go open up tha humungo CRT TV in your backyard! you know? the one you are scared of! :D
Click to expand...

Hey, who said im scared of it :na:

EDIT: I'l probably just make a simple driver with a MOFSET, 2 resistors and a cap to see if the flyback is man enough.
 
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When I can be bothered taking it off the shelf. It weighs around 75 kilo's
 
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