ZVS Flyback Driver Nice sparks! / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

ZVS Flyback Driver Nice sparks!

1 2 next

Move Thread

LAN_403

David

Mon Mar 12 2007, 10:46AM

Registered Member #552 Joined: Mon Feb 26 2007, 08:42AM
Location: Galicia, Spain
Posts: 5

First of all, nice to meet here, I have been trying to register for moths, but it was disabled and the mails wont do anything. My name is David, I'm from spain and 20 years old, this year will be 21 hehe.
I made an electronics studies, but when i made some sparks I got engahed by de HV. I burned lot of transistors, especially those 2n3055s wich are the worst iÂ´ve seen for flyback. Two weeks ago I decided to make this circuit, I was really impresed about its power.
Im using the improved version of the zvs circuit from Vladimiro Mazilli. Dunno the power, I think it will be over 350 W. now the driver is dead, as it sometimes it doesn't oscillate, and I was using a rewinded MOT so lot of current passed trought the IGBTs and they exploded (no oscillation = total shortcircuit). Using 40V that dropped to 34V with the 15cm arc. It ignites at 5 cm, but the current is so high that the arc can be distanced up to 15 cm. Flyback needs to be inmersed in oil, otherwise it arcs with everything it finds: table, primary, even the hv cable isn't enought to insolate so high voltage, I have to use a 20 cm plastic thing to keep sure that it wont hit me hehe.

15 cm arc! panic! haha.

41 secs arc video, just 7cm.It was the first time i tried the rewinded mot and the circuit wasn't well optimized. Without spacers and a few turns more on the MOT it got lots of more power.
That big 50hz noise wasn't the arc itself, was the MOT wich secondary was bad assembled and it was vibrating making a lot of noise. All that has been solved, so nexts videos I hope will be better sounded.
Frequency was over 25 KHz, great for my ears, I was fed up with the 2n3055s oscillator always running over 16KHz, disturbing everyone near it.
Now just the cat seems to be angry when i connect it haha
Sorry for the bad quality, I just have my mobile phone for making videos and photos...
]1173698123_552_FT21961_mov01034.avi[/ file]

Myke

Mon Mar 12 2007, 01:23PM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

Nice

. Could we please see a pic of the driver and the setup?

ShawnLG

Mon Mar 12 2007, 04:07PM

Registered Member #286 Joined: Mon Mar 06 2006, 04:52AM
Location:
Posts: 399

Awesome. Where are you hiding that MOT?

Dr. Dark Current

Mon Mar 12 2007, 05:45PM

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

That's really nice. You must have a tough flyback here because in my experience the internal diodes in the flyback usually toast in seconds with that kind of power.

Electroholic

Mon Mar 12 2007, 08:07PM

Registered Member #191 Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720

i see a ferrite transformer in the bowl of Si oil.
solid state MOT?

uzzors2k

Mon Mar 12 2007, 08:42PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

Those are pretty powerful arcs, what kind of transformer are you using? I've got a short-circuit protected MOT power supply, 50V, so I'll have to do some more ZVS experiments soon.

David

Tue Mar 13 2007, 05:20PM

Registered Member #552 Joined: Mon Feb 26 2007, 08:42AM
Location: Galicia, Spain
Posts: 5

Haha none MOT here for making sparks.

Dunno why the flyback survives... When i tried the first time the power wasn't so high so it was strange that it arced itself to the ferrite or the primary, but when i tried with the MOT, thanks God I was using that plastic thing to move the HV cable, few seconds of a big capacitive corona discharge between the the plastic base and the metal table, and the plastic heated up, arcing to the metal table.I was at a friend's house, my table its wood, but still burned every where by accidental arcs. The plastic was 0,5cm width, seems to be PVC
I was really impresed too, used to make 3-4cm low power arcs, when i gave power to that...

When there's no arc, lost of corona is discharged in air, like a small sstc.
Here's my setup configuration:

- MOT rewinded to give 40V, with 4mm (i think, maybe 3mm)cooper wire for providing almost 50A without overheating
- "Brick" diodes; 120A 600V 80nS ultrafast rectifiers, can power almost anything ;P
- Filtered with three capacitors with a total of 11,300ÂµF at 50V

This is the circuit

Some setup pics...
I mounted the circuit quickly and bad,just for make it look like it is normally, as I had dismounted it, to mount it again when i receive new IGBTs...

Rewinded MOT..

brick diodes

other angle, brick diodes again

caps..

driver, with screwed igbts still mounted xD

another angle of the driver

flyback, everything screwed up ;P capacitors disconected by one side, the orange wire is the anode of the flyback, i take it to make arcs far of the primary for insurance hahaha

another pic of the flyback

and the lastone..

Also had tried to put a secondary self-made with less turns to give over 1-2KV, arc jumps at little distance but it can be distanced more than 1 cm, burning the electrodes quickly, even 4mm diameter steel electrodes burned up, maybe i can use this to make some welding thing hehe. No pics yet, i'll make someones when i get new igbts. Great arc-spark-emitting effect, dunno how to explain it in a good way in english hehe :P

Dr. Dark Current

Wed Mar 14 2007, 04:01PM

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

I have one question: since the driver produces a symmetrical waveform, how it comes to that the flyback doesn't instantly explode when drawing an arc? I'm asking because there is a HV rectifier in the flyback, so shouldn't it put dc "bias" on the secondary and instantly saturate the core?

Steve Ward

Wed Mar 14 2007, 04:37PM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

I have one question: since the driver produces a symmetrical waveform, how it comes to that the flyback doesn't instantly explode when drawing an arc? I'm asking because there is a HV rectifier in the flyback, so shouldn't it put dc "bias" on the secondary and instantly saturate the core?

A fair question indeed. There may be a few things keeping these types of circuits working OK. Firstly, the tank circuit is resonant with a pretty good Q, meaning that energy is left over cycle after cycle. When the output is forward biasing the diodes, the Q goes down (since energy is being extracted by the arc) but on the reverse cycle, energy is only being added. But, why should it saturate provided the V*s product for the core isnt exceeded? But you are right in thinking that this circuit would be much better suited with an AC flyback, or at least something with full-wave rectification.

sparky

Thu Mar 15 2007, 06:42AM

Registered Member #530 Joined: Sat Feb 17 2007, 07:56AM
Location: Victoria BC, Canada
Posts: 178

Steve, have you tried linking 2 flybacks in a series arrangement using this high wattage driver?? ....might be a bit overkill - but 100 kV sounds FUN, especially at 300 watts or so!!

1 2 next

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