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Cheapy high power CFL flyback driver.

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LAN_403

Platinum

Mon Nov 28 2011, 10:07PM

Registered Member #3926 Joined: Fri Jun 03 2011, 08:32PM
Location: UK.
Posts: 525

Because my circuit building skills are not very good compared to the rest of you here (although I can build basic circuits now) I used to drive flybacks with anything, but I've experimented alot with CFL ballast drivers.

I've gone through about 20+ CFL house light bulbs. I'll show two videos in which I run a flyback from a 10W light bulb ballast and with and without a small 1KV cpacitor (as big as you little finger nail). The capacitor is in series. It changes resonance I think because the ballast is not audible (20khz+) to your ear so the frequency is very high, but when you use a cap it lowers closer to resonance with the flyback.

Excuse me and the quality of the webcam. It looks better in real life.

Without:

With a small 1KV cap:

I have a bank of 5 caps to make a 2000~v cap bank and it works even better than the one in the video but I'm not going to try it as it might blow the CFL like the last one. I'm also going to put a capacitor in series with my 200W halogen transformer (should arrive soon) to see if I can get better output. But I think this driver is useful because it's not low power (I actually brushed my arm against the flyback output and I jumped, feel a bit wobbly lol) and can charge my coilgun.

BE CAREFUL! I've very careless I just acted as a ground for the flyback to use a good chicken stick and don't be a fool like me. I used a pliers and the flyback went through the insulation, and went to ground and I felt my trainers vibrating like it's arcing.

Platinum

Tue Nov 29 2011, 04:01PM

Registered Member #3926 Joined: Fri Jun 03 2011, 08:32PM
Location: UK.
Posts: 525

Sorry about the videos I just updated the second video with a cap. I'm also potching around with my PS3 PSU flyback driver. Very good arcs check the video if you like :).

Thomas W

Tue Nov 29 2011, 04:23PM

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

interesting... now try this:
get the output of the CFL into a cheap IGBT halfbridge/ fullbridge
and drive the flyback off that :D

Platinum

Tue Nov 29 2011, 04:28PM

Registered Member #3926 Joined: Fri Jun 03 2011, 08:32PM
Location: UK.
Posts: 525

I do not have any IGBT's :( My 200W flyback driver died today so I'm going to make another one.

I'm also going to run a flyback off a PS3 PSU, and the epic thing is that, there are 4 pots on the PSU (APS-227), one for Over current protection, and 3 other are for frequency! so I can get the flyback to resonate!

MY PS3 POWER SUPPLY FLYBACK DRIVER IS WORKING!! incredible output, I will make a video in a bit, incredible, very high voltage the spark gap is over 80mm's! and high current, the supply is 400W.

Ash Small

Tue Nov 29 2011, 08:34PM

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

That's quite impressive, Platinum.

I've not heard of anyone using resonant capacitors with CFL power supplies before.

I'm sure you can develop this idea quite a bit, using different types and values of capacitor, etc.

It will be interesting to see where this thread goes.

Platinum

Tue Nov 29 2011, 10:26PM

Registered Member #3926 Joined: Fri Jun 03 2011, 08:32PM
Location: UK.
Posts: 525

Ash Small wrote ...

That's quite impressive, Platinum.

I've not heard of anyone using resonant capacitors with CFL power supplies before.

I'm sure you can develop this idea quite a bit, using different types and values of capacitor, etc.

It will be interesting to see where this thread goes.

It seems that high voltage capacitors are much better, the output of the CFL is about 1.2KV so a 1KV cap is good but I made a bank of 5 500V caps to make 2.5KV bank and that is alot better, the capacitor are ceramic I think.

Ash Small

Tue Nov 29 2011, 11:51PM

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

It will be the value of the caps rather than their voltage.

It may just be a 'Tesla tank circuit' that you've created, with an inductor (the flyback primary) and capacitor.

It's certainly worth further investigation.

Platinum

Wed Nov 30 2011, 12:01AM

Registered Member #3926 Joined: Fri Jun 03 2011, 08:32PM
Location: UK.
Posts: 525

I do not have any more CFL's but I will get some higher power ones in a few days at B&Q. But when you use a capacitor to make it give out more power, you risk destroying the whole thing so if you want to do this you probably already now get a quality circuit.

I used a tesco 20w bulb and it didn't last a few seconds, I used a Phillips 12W bulb and it lasted very long until it arced over, and kept arcing.

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