SSTC wıth a balast

[Emre]

I stumbled across this video

and tried to replicate his tesla coil. Everything is the same other than the balast. İ have a 250w 3amp balast but he used a 1 amp balast what can i do to fix this or is it still doable as it is?

[Emre]

welp i tried it and the irfp460 blew up. xD
can someone help? 

[FilipŠebík]

Yeah, it should be like this

[Emre]

Thank you so much, you're a legend. I will test this out as soon as my new batch of irfp chips get in!
A few more questions. Will the 250w 3amp balast be too much? He used a 250w 1 amp balast. And is it really this simple? Do I just wire the balast like that straight in from mains?

[FilipŠebík]

The ballast will allow only around 250W to pass and current about 3 amps, your will be better and may not heat at all and yes, it is this simple to wire a ballast from mains.

[Fumeaux]

Yeah, it should be like this

What about those zeners? They should go across the gate of the mosfet and Gnd.

More like this:



Just that the Poti substitutes R1 and R2

And most likely if the schematic asks for a 1A choke you will need a 1A choke and not a 3A.

[Emre]

Yeah, it should be like this

Hurray! It didn't explode !!! Thanks, now all I need to do is find a way to tune it. Any suggestions?

[Emre]

I really need help from you guys and gals! <3
The circuit allows electricity to pass through I can tell because of the humming of the ballast and the heat emmited form the mosfet and diode (uf5408).
But there are no sparks forming on the tesla coil. What could the problem be? The capacitor? The amount of winds on the primary or secondary coil? I have just under 1000 turns on my secondary coil and the copper wire is 0.5mm thick. how many turns should I have on my primary coil and how thick should it be, also what material is best?

[dexter]

But there are no sparks forming on the tesla coil. What could the problem be?

try connecting the primary coil the other way around

[Emre]

But there are no sparks forming on the tesla coil. What could the problem be?

try connecting the primary coil the other way around

The primary and secondary are both turned in the same direction.

[dexter]

connecting the primary coil the other way around even if both coils are turned in the same direction is still the first thing to try on a secondary feedback based SSTC when you get no sparks

[FilipŠebík]

I would say, try to rearrange those zener diodes like Fumeaux showed in his fixed schematic.

[Emre]

But there are no sparks forming on the tesla coil. What could the problem be?

try connecting the primary coil the other way around

Omg you were right... I had the primary coil connected incorrectly, now its kindaa working??
When I turned it on the light (also on) dimmed ever so slightly! I thought it was just my eyes playing tricks but i got someone else to confirm it and yes the lgiht almost 3 meters away from the coil dimmed for some reason!
Now what should I do, do I have too many turns on my primary?

[Emre]

I would say, try to rearrange those zener diodes like Fumeaux showed in his fixed schematic.

Thank you guys soo much btw y'all are life savers!
How should I change the zener diodes? I didn't quite get that. sorry

[Emre]

I had the secondary coil hook up to the emmiter of the transistor, I believe this isn't how its actually supposed to be. I think it should be hooked up to the same wire as the base of the transistor. will test now.

[Laci]

Just to avoid confusion: MOSFETs have source,not emitter.

The zener diodes should have their anodes connected together and the other two ends to MOSFET gate and supply negative,to protect the MOSFET gate from over/undervoltage.

Try turning the potentiometer to find the best offset voltage for your MOSFET.

Your ballast outputs DC or AC?

[Emre]

Just to avoid confusion: MOSFETs have source,not emitter.

The zener diodes should have their anodes connected together and the other two ends to MOSFET gate and supply negative,to protect the MOSFET gate from over/undervoltage.

Try turning the potentiometer to find the best offset voltage for your MOSFET.

Your ballast outputs DC or AC?

Thanks!
The ballast doesnt specify on it. It is a magnetic ballast. (https://www.3faz.com/yildiz-250w-metal-halide-balast-yildiz-250w-balast?gclid=CjwKCAjw-4_mBRBuEiwA5xnFILMfN0Ybm14MaD_8JeIiclpmyEi0KltvBJWAxysTV4xkCt2L8NNqBBoCgw8QAvD_BwE this is it)

[Laci]

The ballast doesnt specify on it. It is a magnetic ballast. (https://www.3faz.com/yildiz-250w-metal-halide-balast-yildiz-250w-balast?gclid=CjwKCAjw-4_mBRBuEiwA5xnFILMfN0Ybm14MaD_8JeIiclpmyEi0KltvBJWAxysTV4xkCt2L8NNqBBoCgw8QAvD_BwE this is it)

Sorry for the stupid question,I saw the crossed NAME of the diode and thought that it's omited,but if not,then it doesn't matter if the supply is AC or DC.

[Emre]

Nothing changed. What should I do now? it's not shooting archs out the top yet xd. What else could the problem be?

[Laci]

If you're in a rush,then make a small compact circuit,as it doesn't require much components.Mount the MOSFET on a solid heatsink,bend the gate and source out a bit for more space and solder the zener diodes directly on these pins,just like the gate resistor,according to Fumeaux's schematic!Make sure nothing connects to the heatsink expect the MOSFET.Solder short,but enough wires to the potentiometer's legs and solder these to the right points.If you have long enough wire from the base of the secondary coil,solder that directly to the base too,make sure it doesn't touch other metal parts.Use the thickest wire you have as primary for a good magnetic field coupling.

The best way to try out this circuit without blowing up the MOSFET is to use a low voltage source,like a transformer rectified for DC.Add a fluorescent light bulb close to the upper end of the secondary.The first thing to do is rotating the potentiometer and see if the light bulb lights up.If it doesn't,then change the direction of the primary.If it does,find the position where the light bulb is the brightest.After you found the best point you can increase the input voltage.

If the MOSFET blows up you can either have gate overvoltage mainly due to bad zener diodes or wrong connection,or too much drain current.To decrease the drain current you can add a few more turns to the primary coil,but too much turns will decrease the length of the arcs,so use more turns while testing.

For a better design and longer arcs you should read other people's projects here and of course the websites which has most of the knowledge required to build a great Tesla coil,for example:
http://kaizerpowerelectronics.dk/tesla-coils/

https://www.loneoceans.com/labs/