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Reaching

Mon May 29 2006, 08:27PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

yeah Time for a new Teslacoil project.

This time i want to build a interrupted solid state teslacoil. the most important thing, it has to be reliable, sparklenght is not important (okay some 7" streamers or so is a must).
i already made a nice pcb with everything together, halfbridge of irfp460s, driver etc. okay, at the moment the driver has a simple 555 oscillator but i want to go secondary base or primary feedback if its possible with an isstc(i think so) to prevent frequency trash due to the interrupter i made a nice circuit with an D flipflop to synchronise hf and interrupter signal, that works just fine.(74hc00,74hc14,74ls109) Driver ics are Icl 7667 (only 2A Driver ics)

within the next days iÂ´ll build everything in a nice 17x15x6cm case (secondary and primary on top)
the secondary is 7,5cm in diameter and 20cm high, wound with 0,17mm wire , 10cm stainless steel sphere on top, resonant frequency, exactly 300khz.

so, someone can tell me whats useful for a reliable isstc, primary or secondary feedback? the isstc is for a physics week at school so it has to run several minutes and longer with a teacher at the interrupter

you know what i mean?

heres a pic of the nearly finished prototype pcb

Update 4.06.06

i almost finished the new primary which fits fine on the top of this nice small case. just have to screw it all together. i thought about making it drsstc and i think i will give it a go after i tested it isstc. a nice small drsstc just a bit larger than my drsstc5 which is one of the worlds smallest drsstcs.

okay, heres the new finished primary

the primary is 8cm high to give you idea of the size , 9 turns of 6mmÂ² copperwire,, yeh with strikerail i need it when i run it drsstc

Marko

Mon May 29 2006, 08:44PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

I like the small cute board.
Sync circuit was probably unnecessary for hard-switching ISSTC, unless you want to turn it into a DRSSTC later

I had my ClassE SSTC running CW for several hours at display, and it set it's topload on fire when I brought it and ran it at home

But it was much, much smaller than yours, with only 2,5cm secondary and ping-pong ball topload.
Gave some 1,5cm sparks at 20V, but it's job was anyway to power a resonator and motor few meters away.

With 'teacher on interrupter' I think you should make it totaly reliable in CW first, and then put an interrupter for less heating, etc..

Reaching

Tue May 30 2006, 09:38PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

my case arrived today and now i can show you how it should look like when its finished.
tommorow: Primary and secondary

heres a pic

Marko

Sun Jun 04 2006, 06:37PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Where did you get the sphere?

Reaching

Sun Jun 04 2006, 07:37PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

i got the sphere from my local "baumarkt" dont know the right word, building market
i found it between candlelights etc

,never thought that they have something like this in this store, . really cheap though only about 2$ for this one 10cm in diameter,. they have several sizes from small to the really big ones (about 60cm in diameter for around 120$) they sell identical spheres on ebay too.

Marko

Sun Jun 04 2006, 07:58PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

$2 is dirt cheap, and it looks very nice!
Just compare it to something like Information unlimited

primary feedback if its possible

And yes, you can't make primary feedback without primary cap.
Only if you want to tun it into a DRSSTC later.

Philcogrump

Mon Jun 05 2006, 03:59AM

Registered Member #212 Joined: Sun Feb 19 2006, 05:42PM
Location: Texas
Posts: 20

You probably could get a sphere like that from a garden store or something, they are usually painted for decorations. My mom bought several and put some in the pond. After several months, the paint began to strip off so I pulled one out of the pond and stripped the rest of the paint off using paint thinner, then the result was a nice steel sphere. I used it for one of my tesla coils, works very interestingly as opposed to the toroids because of the smooth surfaces. The sparks move around smoothly, I assume this is called the Banjo effect?

Anyway, looks like a nice ISSTC, Reaching. Looking forward to seeing photos of it in operation.

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