Video of My High Voltage ZVS Flyback Driver

Hello peeps.
I made a video of my new ZVS driver. It's a neat little High Voltage project. I like it alot because it makes some pretty impressive arcs considering it's so simple to build. I don't usually make any videos but this was special. So I'm writing this in the hope that some of you might want to build one of your own. After all, I can't be the only HV tinkerer here.

This isn't your typical flyback driver. It doesn't make puny hair thin blue sparks. It makes some pretty fat crackly sparks. They behave much like sparks out of an AC transformer. They're not noisy at all. At 40v it will make arcs up to 8 inches long! Now I gotta figure out what to do with it. Up till now I've just been frying old circuit and CDs, I'll try to get a video of that too! :eg:

Here are some pictures:









So here is the video, sorry for the shakyness. I filmed this with my iPhone and it was late. :tinfoil:



Here is the schematic:
http://sites.google.com/site/uzzors2k/mazzilli_zvs.png

Here are the main circuit components I'm using, I got them from Futulec
-MUR1560G - 15A 600V Ultrafast Diode
-IRFP250 - IRFP250 MOSFET N Channel Transistor
-1N5349B - 1N5349B 12V 5W Zener Diode
-R470R5W - 470ohm 5W 5% Wirewound Resistor
-1/4w 10k ohm Radio Shack Resistor, it doesn't need to be high wattage.
-The capacitor is the tricky one. It must be high quality and non electrolytic. I got mine from an old power supply I had laying around. Computer power supplies often have high quality "X2 MKP" caps in them, so look around and you might find a suitable one. But either of these should work well too:
VISHAY ROEDERSTEIN|MKP1839 468 084HQ|CAPACITOR, AXIAL, MKP, 850V, 680NF | Farnell Australia
CORNELL DUBILIER|CD19FD681JO3F|CAPACITOR SILVER MICA 680PF, 500V | Farnell Australia
-The inductor can also be tricky to find, I found a 1 in diameter round ferrite toroid out of the same power supply I found the capacitors in. I wrapped it with 20 turns of thick magnet wire. That was in the ballpark, there is some leeway on the inductance on that part.


Tips:
-Wrap two coils of 5 turns on the Flyback, in the same direction!
-If you're running it at less than 20v you probably wont even need heatsinks. Mine barely even get warm even when the circuit draws over 500W!
-You'll need to find the ground tap on the bottom of the flyback. You can do this with an ohm meter to find the one pin that is not connected to any coils or just see which pin the arc wants to spark to.
-If you're going to use rectified AC you mush have large smoothing capacitors. It really makes a difference in performance. I've got about 5000uf on mine.
-The capacitor should be soldered as close to the primary coil as possible to prevent stray inductance. That's why it's not on the board.
-A couple of power drill batteries or RC car batteries make a pretty good DC source. But a couple of 9v batteries wont cut it.
-The high voltage currents this circuit makes WILL KILL YOU!!!! Again, if it bites you across your arms then all the power will flow over your heart and stop it. Always put one hand in your pocket when playing with sparks and unplug the device, not just flip a switch, when you make changes.


Here are some more links :wave:
flybacktransformer - uzzors2k
Mazilli ZVS flyback driver | Kaizer Power Electronics

:beer:

-Tony

wow, i think ill have to try to make one of these some time! if you dont mind me asking, how much was the total cost for parts?

It depends. The most expensive part is probably the high current DC supply. That could be a couple of big batteries or you can get a variac like I have. I got that for about $150. But I use it for other stuff too.

You could also cut away the secondary of a microwave transformer and rewind it with heavier gauge wire to get the voltage you want. The number of turns will affect the voltage.

The circuit electronics are cheap. All said and done you're looking at about 20 buck on just components. But buy a few extra in case something goes wrong and you burn a part out. It was cheap for me because I either already had or salvage a few of the necessary parts.

The transformers are cheap on eBay. The new style (like the one I have) type are actually preferred for a ZVS driver. Unlike the transistor based push-pull feedback schematics, those call for the old style flybacks.

-Tony

cool, ill have a look into a high current dc supply later, sounds like a good project for the upcoming holidays

Nice variac, where did you find that?

Variacs | AllElectronics.com

-Tony

Very Nice , I made A ZVS But never got the the FlyBack part , I used it as a mini induction heater , , Great arcs Btw

i used to make stuff like that when i was younger, but i cheated and used NST's because FBT's packed in after abuse

Cool vid ...is it possible to apply this device to CO2 laser tube?

Good question. The voltage is certainly high enough, but I don't know if the waveform is appropriate. I'm not sure what frequency those CO2 lasers use.

-Tony

those are some mean arcs

Xplorer877 said:

Good question. The voltage is certainly high enough, but I don't know if the waveform is appropriate. I'm not sure what frequency those CO2 lasers use.

-Tony

Click to expand...

The followings are some parameters of a "classical" PS for 40W CO2 tube:

# Input voltage: AC 220V+30 or AC 110V+20 (to be specified when placing order).
# Maximum output voltage: DC25KV
# Maximum output current: DC 20mA
# Isolation Withstand voltage: Input-output, input-enclosure: AC2000V-10mA-60s; negative pole of output connected to enclosure
# Protection: with well-grounded enclosure, output circuit of power supply can be open for short time (but arc between positive pole and enclosure should be avoided).
# Response time (from time of input being available to the output current being up to nominal value): ≤1ms.
# TTL voltage level control: effective voltage level can be high or low through setting

Well most flybacks have a diode built in on their output so the output is DC. It doesn't say it has to be smooth DC. From what I've read about them I think a ZVS based driver would work, but I'm not 100% sure so get a second opinion first. The inductor value can tune the ratio of output voltage and current for a given input wattage.

If you try it you'd wanna make sure you're outputting the right voltages and currents. I'm not sure how sensitive those tubes are to their voltage input. I'd assume that as long as you had sufficient cooling you shouldn't damage it as long as you didn't exceed the input voltage, regardless of the waveform.

-Tony

Since the frequency of the flyback is so high, and the current is so low, a much lower capacitor value can be used to smooth the DC.

^Correct
So CO2 tubes do need smooth DC?

If figured the lasing would emulate the voltage waveform. Like if you had a square wave you'd get pulsed output.

I've never really been into tube lasers much. I think I may make another Tesla Coil out of it.

-Tony

I don't think they need it, but they run more reliably with longer tube life with it.