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Tesla Coils and BS2-based drivers? — Parallax Forums

Tesla Coils and BS2-based drivers?

xanatosxanatos Posts: 1,120
edited 2010-11-20 19:22 in BASIC Stamp
Looking to make a solid-state Tesla Coil using a BS2 and some small Qs to drive some of those huge brick-style MOSFETs and switch some HV at high frequency. Before I potentially reinvent the wheel here - has anyone else dabbled in this arena? I have built regular TCs before, using mechanical spark gaps - but I want something MUCH more efficient and quiet now that can be controlled by any of the eloquent means that using the Stamp may afford me...

Thanks for any advice or direction as to where to find previous incarnations of such a project - if they exist...

Dave

Comments

  • Peter KG6LSEPeter KG6LSE Posts: 1,383
    edited 2010-11-18 13:26
    I have seen PICs used for SSTCs

    I use only SGTC . kinda hard to switch 10KW ,

    so its a pole pig and a rotary for me ..

    becasue the BS2 runs slow on the whole 8K lines a second is not that fast .. it may not be able to do a PLUSEOUT fast enough to drive teh fets .
    now if its used as a controooler it may work with a external DDS or PLL based chip .

    I would recomend a Prop if you can .
  • xanatosxanatos Posts: 1,120
    edited 2010-11-18 16:13
    Wanting to keep this one fairly small, and it needs to be DC powered- from a car battery in fact. Probably run a 500T secondary and shooting for a Fr of around 300 to 400kHz. I can drive the pri at a subharmonic that should be in the range of BS2 control - I'm thinking anyway. If not, I can do BS2 to PLL... probably use the BS2SX to start with anyway. Prop could work but I'd need a bit more experience with it. I'm fluent in BS (!) but not in prop or Spin yet.

    This is an odd coil project in that I need to run multiple coils whose fields interact in specific phase relationships. Oddly enough, the PWMPAL may actually provide me with the specific control I need but in a very "not what it was designed for" way.

    Not wanting to mess with pole pigs - they scare me! :-) Plus they're too big!

    Shielding the control box should be a project in itself - quite an exercise in isolation, noine immunity... faraday cages... who knows! :-)

    Keep me in mind if you should have any enlightening thoughts along these lines!

    Thanks,

    Dave
  • Peter KG6LSEPeter KG6LSE Posts: 1,383
    edited 2010-11-19 21:35
    Oh Yes yes if you use the PWM pal It should work way better ..

    I little hint from a friend who made a HV Current probe

    use Fiber Optics for your run from the BS2 / PWM pal to the Brick FETs IN th e tank circuit .

    this way you have complete isolation ..


    Look up "Arc attack" . I have seen there setup . talk to them . there Driver is Very good.


    I mostly focus on BIG coils . for stunts not for light weight transport MIDI control . But some time once I have a place to do more coiling Ill be doing a 10 KW SSTC.
    With modern Semiconductors I don't for see any Huge hurdles besides cost ..

    5 years ago a 2KW coil would be thought of as Nuts , Now we have guys with no RF design experience make 6KW ones ..

    I think it should work as long as you can acheve resonance ...
    Now cause your coil will be small it will have a relatively high resonant Freq .

    this is counter productive to the the PWM pal .

    I have never used it but If I understand what It does correctly, it the coil should work .

    what kind of drivers ; push pull ? half bridge full bridge ?
    are you planning on .

    If I was doing this I would use a split PRIMARY and sink each leg to GND .

    I used this concept for a large(80W) CO2 Laser PSU based off a flyback Xfmer with great success .

    I used the 556 as a PWM ...

    I would use a DC-DC to up that 12V to 400 and chop there ..

    look at first getting 400V or so .
    250 is OK too.


    Secrit !!! 99% of power inverters are a HF SMPS . So you can tap the 100+ volt HVDC right befor the 60 Hz H bridgeFETS to steal power at DC .
    Use a UK Power inverter as there 250 V or so
  • xanatosxanatos Posts: 1,120
    edited 2010-11-20 06:10
    Yes- the fiber optics are a fantastic idea. I hadn't thought of that just yet, although I remember seeing something like that a few years ago when I was messing around with another coil setup. Thanks!!!

    ArcAttack was AWESOME! Worth the visit just to watch Elijah Wood in the chain-mail suit taking those HUGE arcs. Hard to believe you can't feel those things at all!

    Now I just need to see if I can get the schematic in a better medium than printed on a Tee Shirt! :-)

    Dave
  • Peter KG6LSEPeter KG6LSE Posts: 1,383
    edited 2010-11-20 19:22
    xanatos wrote: »
    Now I just need to see if I can get the schematic in a better medium than printed on a Tee Shirt! :-)

    Dave
    I got the shirt for the same reason LOLS...

    I got some pointers from KVA FX ....

    sadly My Old lady wont do MIDI LOLS . but it will do 8 to 12 Footers .
    I started in coiling back in 2001 .
    and have made 6 coils
    alpha 300W . long john 1kW > , neo 1.4kW , white lightning 3kW , Mini me 300W ,venom 10kW.. [[[[[Wolverine 10kW+ WAS my next but I moved to Iowa in to a dorm . ..

    One day Ill make a SSTC . there SO cute to play with ..

    the fiber was from terry fritz I believe .

    http://www.pupman.com/
    is the place to go for Info ..
    Peter
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