Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

Buy Site Supporter Role (remove some ads) | LPF Donations

Links below open in new window

FrozenGate by Avery

Tesla Coil Build Thread

Atomicrox said:
@Po210:
Relax, I said it self starts with an interrupter but not on CW.
No one is slamming you and even though you stopped answering my emails a few months back (for no reason at all) I still went with your schematics because AFAIK you have the best non-DR SSTC coil.
Click to expand...

That wasn't directed at you. Sig said my board wouldn't self start. I never had any issues with the coil, it's been running on the same components for 2 years now.

As for the emails. I stopped checking that email address because my account was hacked and 99.9% of the emails I get are spam. As well as I have been going through a tough time with depression having my wife cheat on me and divorce me for another guy. So no reason at all....
 





I did not mean to slam you or your board at all. I do not doubt your design or driver boards work, I've seen your vids! I mean no personal insult or derision.


I've just been referring to the board I have from you that I populated as "the Po210 driver" because I have nothing else to call it. I don't know what went wrong either. I chalked it up to the parts I used differing in make (but not model) to yours. I followed your parts list and there are no construction errors. The interruption pulse train network never worked out of the box, it fried the Schmitt ICs into latch ups, and would not oscillate. I traced it to the fact that the 5v Schmitt was getting 12v on input from the fiber optic receiver which exceeds design parameters. Upon removing the output bias on the receiver and changing the Vcc to the reciever to 5v from 12v the board began to function more normally. It still would not self-start in either CW or interrupted but it would oscillate and not latch up. I put it aside as removing the interruption network entirely did not bring about self-starting and at that point the circuit is functionally no different than tons of drivers which run CW all the time (ant to cap to Schmitt to ucc chips to cap to GDT).
 
Awesome, Twirly! One of these days I really need to take the plunge into tube coils.
 
Sigurthr said:
Awesome, Twirly! One of these days I really need to take the plunge into tube coils.
Click to expand...


Thanks :D , You should , they are a lot harder to kill than a SSTC , a lot harder :P


SAM_1003 by TwirlyWhirly555, on Flickr

hardest part is the tuning , where a SSTC will do most of it itself with a self oscillating design the VTTC has to have the LC primary circuit manually tuned to secondary frezz for it to work , But its worth the effort :D

Just get good capacitors for the primary , like the Russian ones , physically big for the cap value


SAM_1006 by TwirlyWhirly555, on Flickr



Ive just made a new secondary that's 2.5" x 5" , with 4" of windings , output as of now is 9" - 10" , but this 811a is at its absolute max dissipation the anode starts to glow red . So im going to get the 572B which is a drop in for the 811a but instead of 40W anode dissipation it has 200 Watts dissipation xD

primary is 30 turns ( not the best spot I think ) , Feedback is 14 turns , tanks cap 1.5 nF and coil is interrupted in sync with mians .


SAM_1012 by TwirlyWhirly555, on Flickr
 
Last edited:
The biggest hurdle for tube coiling I've found is finding a source for the parts! Simple things like the power resistors, doorknob caps, and tube stand base are way expensive and hard to find. I remember last time I looked I couldn't find an 811A for less than $50, and the base was another $35. Caps were like $20 each and I'd have needed about six of them.

Do you get all your stuff off fleabay or is there another source you've been using?
 
Sigurthr said:
The biggest hurdle for tube coiling I've found is finding a source for the parts! Simple things like the power resistors, doorknob caps, and tube stand base are way expensive and hard to find. I remember last time I looked I couldn't find an 811A for less than $50, and the base was another $35. Caps were like $20 each and I'd have needed about six of them.

Do you get all your stuff off fleabay or is there another source you've been using?
Click to expand...

no idea of my total cost but I just randomly find parts on web :P , Ebay mainly

my 811a cost 10 usd and I never used a base I just made my own from terminal blocks the caps cost 40 usd for 3 of em , MOT was free , Power resistors I just use light bulbs so 25p per one , i think ive spent most on rectifier diodes more than anything else , as i blow them up a fair bit xD

My GU81m pentode cost me 80 GBP NOS , A brand new 811a cost around 20 usd + shipping ,
 
Last edited:
I was wondering about the bulbs, haha. I thought maybe it was a ballasting system. Ok well that certainly cuts down on the cost. How are you putting the parallel chokes on the "resistors" then? Perhaps that is how you're blowing diodes...
 
Sigurthr said:
I was wondering about the bulbs, haha. I thought maybe it was a ballasting system. Ok well that certainly cuts down on the cost. How are you putting the parallel chokes on the "resistors" then? Perhaps that is how you're blowing diodes...
Click to expand...

Parallel choke ? , Im guessing you mean the resistor and inductor before the tube anode , for that im using just hook-up wire wrapped wound a 10W ceramic resistor .

There arnt any other chokes that im aware of in the VTTC circuit .

The diodes are probably been over volted / over current , 10 diodes rated at 600v @ 6 Amps each seem to survive fine
 
Last edited:
Yeah the anode inductor. But IIRC there should also be a similar setup in the grid leak section. I thought you were using a bulb for the anode as well, nvm then.

What voltage/current are you using for the B+? 6A seems like an awful lot to run in to overcurrent situations given a MOT as supply. It is possible to overvolt them though if you're running a doubled MOT rated for 2.5kVAC secondary side as you would need 7kVpk after doubling. Then again 7kV sounds awfully high for B+.
 
Sigurthr said:
Yeah the anode inductor. But IIRC there should also be a similar setup in the grid leak section. I thought you were using a bulb for the anode as well, nvm then.

What voltage/current are you using for the B+? 6A seems like an awful lot to run in to overcurrent situations given a MOT as supply. It is possible to overvolt them though if you're running a doubled MOT rated for 2.5kVAC secondary side as you would need 7kVpk after doubling. Then again 7kV sounds awfully high for B+.
Click to expand...

Woundnt be every good having a inductor on the grid leak , there is a resistors / cap that's all that's needed for that .

I use a level shifted mot , under moderate load will give around 4 - 5Kv pulses , for tubes like the 811a a level shifted mot is a good supply source . A normal MOT with no level shifting works fine too

ground strikes are the worst for killing the level shifter diode .
 
Last edited:
Ah if you're only getting 5kVpk out of the doubled mot then I don't know why the diodes are dying, thermal maybe? I think you're right about the grid leak, I think I was misremembering something I'd seen. The mental picture of a VTTC is a bit fuzzy as I haven't built one.

What are you using for filament supply, btw? I can't remember the 811A's requirements but that GU81M is one hell of a monster to power.
 
Sigurthr said:
Ah if you're only getting 5kVpk out of the doubled mot then I don't know why the diodes are dying, thermal maybe? I think you're right about the grid leak, I think I was misremembering something I'd seen. The mental picture of a VTTC is a bit fuzzy as I haven't built one.

What are you using for filament supply, btw? I can't remember the 811A's requirements but that GU81M is one hell of a monster to power.
Click to expand...

Might be thermal , guess ill never know really xD

Im using a DC bench top power supply , variable from 2.5v to 15v , max current is 45 Amps out , i use it to power the 811a and GU81m

GU81m is 12.6 Volts at 10 amps , 811a is 6.3 Volts at 4 Amps
 
Played with it again today. The smaller coiled antenna didn't work but I managed to kill the corona with a blob of solder on the tip.
After many minutes playing I tried to force CW touching the antenna with a metal, it worked for a few seconds and blew up again.

This time the biggest damage was on the higher FET's source, with some damage to the gate as well. I'm quite sure it didn't short as the resistor was intact and filled with hot glue.

This might have been my final attempt, it's just too much work for average results... the flyback had a much better success ratio and cost/benefit IMHO :/
 
You must log in or register to reply here.





Back
Top