Tesla Coil Build Thread

[Atomicrox]

Hey ,

Id recomend seperate heatsinks , if you have one heatink you will have to isolate each fet from it

Here is my latest update on mine

Secondary is now 4" diamiter , 5.5" High , And with 230V in rectified and smoothed with 1500uF the output is 5.5 - 6 " firey hot arcs , With Music

Great sound quality, good to see things work even if you don't have the proper materials! I'll have to use stuff like that as well

You can use a PSU power supply for a 12V source, just make sure to load down the 3v and 5v rails with the right resistors to keep the psu in regulation. There are how to's for this kind of thing,

No video as of yet, my variac can't handle the 1250W draw at full power, so I have to run it at <500VA. It looks about the same as normal and sounds identical. It runs at ~180KHz and there are two harmonics at non f/n intervals. One is approximately 3f and the other is somewhere around 10f.

I've modified the PSU already, works like a charm and handles 10+A easily

Cool, don't forget to post a video whenever you can!

 

[Sigurthr]

Ya, TwirlyWhirly/IonLaser gets amazing sound quality with his 4046 PLL stuff. I'll have to try that driver out again sometime. I only tried it once in my early builds before I added half (or more) of the neccessary improvements to the baseline circuit and got poor results. I felt at the time that I didn't need another variable in the mix and went back to schmitt trigger stuff. One of the problems was that I couldn't quite find a balance between phase lock range and center frequency values.

Part of the problem was that I was trying the 4046 out on what later became my infamous Harmonic-SSTC's secondary (which produced harmonics even back when it was a SGTC!!!!!). It is no wonder now, why I couldn't get the PLL to lock on to a frequency. It also became clear why when it was a SGTC, it took nearly 3x the calculated primary inductance to reach a resonance point.... I couldn't find f0 and had to go for f1 (that ~3xf0 harmonic)!

If you get a chance, Ion/Twirly, draw up a schematic of JUST the 4046 section you are using please. That'd give me quite a jump on it next time I want to try things out.

 

[Atomicrox]

Finally gonna buy some IRFP260's from ebay to build this. Can I always substitute them for IRFP260N? According to the datasheet they seem better in every aspect.

Best cost/benefit I found was this one. These are more expensive but the IR logo is much clearer on the picture... Do I have to worry about fakes or should I just get the cheapest?

 

[Polonium210]

If your new to Solid State Coils go with the cheep ones first. You will most likely blow a bunch before you get things working right.

This is what happens when you turn the pulse width up to high

 

[Atomicrox]

o.ô poor things!

BTW great work on this coil. Can you post the schematics for it?

 

[Atomicrox]

+rep for that

Sent you a PM, hope you don't mind.

 

[Seoul_lasers]

nice setup!! :
Being an avid coiler myself, considering getting back to coiling after completing my computer build.

Funds are low at the moment.

 

[Sigurthr]

Very nice Po210!!!

I kind of want one of those board combos really badly, haha! I won't have any budget for coils until my taxes come in though. Are you planning on any future runs of boards? I figure this will be sold out by february or so for sure.

Btw, what mosfets, interupter frequency range, and bus voltage were you using in your video? Those results were quite impressive.

 

[Polonium210]

Very nice Po210!!!

I kind of want one of those board combos really badly, haha! I won't have any budget for coils until my taxes come in though. Are you planning on any future runs of boards? I figure this will be sold out by february or so for sure.

Btw, what mosfets, interupter frequency range, and bus voltage were you using in your video? Those results were quite impressive.

Thanks Sig:wave:
I will have boards left by then, haven't been trying real hard to sell them as I've been busy dealing with personal matters.

The coil in the video has a secondary Fres of around 480KHz and the interrupter is set to around 83BPS at 16% duty. I'm using a half bridge of IXGN60N60C2D1 mini bricks IGBT's with a voltage doubler circuit for around 400VDC buss voltage.

I have used IRFP260 MOSFET's and 60n100 IGBT's with this board no problem.

 

[Sigurthr]

Awesome. I have a small ~500khz secondary in need of a new driver as it uses the very first half bridge driver combo board I ever built. I don't use it much because it is kind of a mess and not very portable despite the small size. Your driver board plus a well layed out half bridge would give me that portable show off coil I've been wanting. I need to find nice heatsinks like you're using, I've been using rather small TO264 heatsinks and they can't handle a >700W load for long, even with forced air cooling. I can only run my big 1500W coil at full power for <20sec before temps get out of control.

Yeah, 400v explains it. I'm stuck with 177v and I'm getting about half that arc length at best on my big sstc. Very clean professional looking build btw.

 

[Polonium210]

Awesome. I have a small ~500khz secondary in need of a new driver as it uses the very first half bridge driver combo board I ever built. I don't use it much because it is kind of a mess and not very portable despite the small size. Your driver board plus a well layed out half bridge would give me that portable show off coil I've been wanting. I need to find nice heatsinks like you're using, I've been using rather small TO264 heatsinks and they can't handle a >700W load for long, even with forced air cooling. I can only run my big 1500W coil at full power for <20sec before temps get out of control.

Yeah, 400v explains it. I'm stuck with 177v and I'm getting about half that arc length at best on my big sstc. Very clean professional looking build btw.

The heatsink I use is from a computer CPU. It doesn't really need a cooling fan, I can run the coil full BPS/PW for 2 minutes straight and the heatsink only goes up in temp by 2*C
If IGBT mini bricks are too expensive you could also make a compact bridge like this

I construct my halfbridges sans PC board so there is very little stray inductance.

Why are you stuck with 177VDC? You could easily make a voltage doubler circuit With 2 Caps and 2 Diodes. This would allow you to run around 354VDC and if you run your input though a variac that bumps up mains by 10% ish you would have close to 390VDC Buss Voltage.

There are also limitations to how big you can make an SSTC for output capabilities. This does not apply to DRSSTCs however.

 

[Fiddy]

Hey tesla blokes,

Did anyone jump on the Onetesla kit?

 

[ARG]

Hey tesla blokes,

Did anyone jump on the Onetesla kit?

Wish I had, I saw it at 209$ + 20$ shipping and I was going to think it over some more. Then the next morning I refreshed and saw the reward was no longer offered. They are charging 40$ more AND they expect to deliver in March. Not worth it to me after that.

 

[Fiddy]

Man that sucks!

I just jumped on the first run with 4x 220VAC kits left

 

[Sigurthr]

@Po210

The reason for no doubler is twofold;
1) the dc bus cap cost; I calculated something like 44,000uF to filter ripple to a reasonable level for CW/Audio use at near full power. As is I had to spend a fair chunk on 4x 200v 450uF bus caps.
2) Likewise the losses in a MOSFET will be directly proportional to input voltage in a cc application.

I'd like to get some mini bricks eventually but they're pricy to blow up. I've been using FDL100N50F MOSFETs because I had inherited 20 of them for free. They're great fets really and vastly outperform irfp260s in most applications I've tried. I've only blown two so far as well. I currently have 2 in use, 2 used ones that are still good, and 16 brand new.

The problem in Solid State coiling has for me always been heatsinking and lack of even basic machining capability/tools other than a hand drill. Another issue has been mounting hardware, with no acceptable hardware store for about 100miles I've been resorting to $3 for a single screw, nut, washer, and spacer from Mouser. Zip ties from Walmart hold my primary together and in place, lol! Before I drop serious dough on bricks I need to ensure proper heatsinking. I've been relying on super low RdsON fets with hard driven gates to compensate for tiny sinks.

 

[Atomicrox]

Hey Sig, how do you calculate the required capacitance for a doubler? I got a pack of 10 470uF@250V from ebay for a resonable price and was thinking of using that. I wasn't thinking of CW but still 44mF seems a lot higher than anything I've seen anyone using.

As for heatsinks ebay has CPU coolers for about 5 USD/free shipping. I'm gonna use one of those!