Mini tesla

[oneKone]

So because I'll have to wait another week or two for some igbts I thought I'd make another Tesla coil! This one is 75mm diameter and about 115mm in winding length, so about 885 turns. The secondary still has some sanding and coats of polyurethane to be applied but hoping to get it finished by the end of the week. It will use an existing sstc driver and a simple irfp460 halfbridge.

 As for the topload I think I'll use this 150mm diameter one and order a 200-250mm diameter to replace the one for my drsstc.

[Mads Barnkob]

That is a cute little stubby coil, what is its resonant frequency? You did not include wire size

I'll take a wild guess and say 400 kHz!

[futurist]

That secondary circuit begs for QCW

[oneKone]

@Mads,
I knew I forgot to add a few parameters! The wire size is 0.13mm, I can't recall the resonant frequency but I'll measure it when I get home today.

@futurist,
After I wound it and put on that topload I had the exact same thought! I would love to but I'm not equipped with the skills yet. I'll see how a few more months or learning goes.

[Hydron]

You could easily build a standard DRSSTC using some fast TO-247 IGBTs and a flat primary, then add a buck modulator and higher coupling secondary later to play with QCW operation and probably be able to keep using the same driver and IGBTs (primary and maybe MMC would need to be changed).

[oneKone]

You could easily build a standard DRSSTC using some fast TO-247 IGBTs and a flat primary, then add a buck modulator and higher coupling secondary later to play with QCW operation and probably be able to keep using the same driver and IGBTs (primary and maybe MMC would need to be changed).

you make some good points! ill look a bit more into it.

@mads...... your 400khz guess was basically spot on! with topload the resonant frequency is 370khz.

so a small update,
i got stung by a bee and am allergic enough that getting stung on the finger affected my hand! it kinda sucks because i've had to have two days off work, and stop my projects. so hopefully in a few days i get everything going again.   

[Hydron]

If you're going to go my suggested route, just make sure you don't put any big electrolytic caps or something soldered directly on the bridge. A few uF of film capacitors (<10uF or so) is OK (actually required!), but you don't want too much if you're going to drive it with a buck modulator later. You'll still want the big electrolytics later, just before the buck rather than after.

[oneKone]

So I'm at a standpoint with this coil. I've been able to get 75-100mm arcs from it but I think I wanna go a drsstc route now. Just a nice simple TO-247 half/full bridge..... I think I'm talking myself into it!

[AndreiRS]

I would assemble it if I had all stuff. Is that coating so critic? I mean, it makes it work better or just for the lookings? One of the first Tesla coil videos I saw a lot of years ago, the guy even did some wire splices on the secondary.

Edit: Ah I just found the answer, someone said that for manual tuning coils he already used splices. But for self adjusting coils, it is better to have it very nicely made.

[oneKone]

@AndreiRS in my case its about 50/50 look and function. without something to hold the windings in place they could easily get overlapped when handling, but i also do about 3 coats then a light sand and another coat. sometimes ill repeat until 10 coats.

i'm going to order the parts to make it a drsstc.... i still have future sstc projects i want to build but this seems like it could be a nice small drsstc project. for when i do build another sstc i think i'll go maybe something like deeds (youtuber) pll staccato interrupted sstc. 

as it sits i think the fate of this project sealed! i think driver board (depending on what i go with) ferrite cores and resonant capacitor this could easily be a sub $100 in extra parts coil.

Edit:
would it be possible for an admin to move this thread into the drsstc section? or would it be better if i just started a new topic?
cheers

[oneKone]

i quickly made a setup and made a video. at least ill have something to reference to when it becomes a drsstc.

[AndreiRS]

Niceee. Did you see that arcing at the bottom? $100 is not much for all that or is it? Here things are way more expensive, so I'm still on more "analog" projects.

[oneKone]

Niceee. Did you see that arcing at the bottom? $100 is not much for all that or is it? Here things are way more expensive, so I'm still on more "analog" projects.

yeah, the coupling was a bit too high! For most parts locally if the price is too high i just buy from ebay or other online shops. even in australia the west puts on a markup compared to the east, so in most cases i buy from the east and even with shipping its still 20-30% cheaper.

i bought a drsstc controller, resonance capacitor and two n30 ferrite rings for $49 aud. the drsstc controller is from aliexpress and the capacitor and rings are from rs components. i have on hand the igbts and two other cores (4 cores total to make two 1:33:33 cts) and a toroid. Hopefully a powersupply, capacitors and acrylic will come under $50.

[Mads Barnkob]

Just make a new thread with a fresh start for this is a DRSSTC, in the DRSSTC section

Looking forward to see this outperform itself, always keep the camera rolling! Even videos of flash overs and explosions is entertaining to watch.