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24" SSTC build

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LAN_403

Killa-X

Fri Apr 30 2010, 01:55AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

Little ways into the project, but I have a few pictures of its current state. I decided to take my origional SSTC circuit from long ago, and place it into a case. For now, it's a halfbridge. Later, fullbridge.

Some stats
* 4.5 x 24" Tesla Coil
* 24awg magnet wire HeavyBuild
* ~350Khz resonance
* Roughly 1075 windings (TeslaMap)
* Primary Form 6.5" with 7 coils
* Input 8A variac into a voltage tripler.

Coil

Base Nylon Bolted to frame

Insides (Not finished)

Main driver board

I still have a lot to do, Mainly coat the wood base in poly. I still need to wire everything up, place LEDS inside, Install Volt / Amp analog meters, and switches. This coil will operate on a fiber-only system. My Interrupter (Steves Burst-Mode DRSSTC one) emits IR to a IR detector inside the coil. This system also works very clear for midi files.

Note: The output is small in this video so I could have it running for over 30 mins without over heating. I was able to do this with 8" streamers, and it was very loud.

This was my last audio modulation system. It sounds clear, but it sucked. The IR LED and receiver where not a pair, so it had limited frequency. I did an audio test on a true pair, and it was a LOT more quality, and it had no issue doing low to 20khz pitches. So this coil should sound a lot better than that video, since only some instruments worked.

*Image updates will be posted as work goes.

dmg

Sun May 16 2010, 04:54AM

Registered Member #2628 Joined: Fri Jan 15 2010, 12:23AM
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Posts: 627

Nice work so far...
If you dont mind me asking, what are the ratings of the fets are you using?

Killa-X

Wed May 19 2010, 12:47AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

The mosfets are rated 500V at 48A, 500W.

I recently did a test today, with wires spewing out all over, and it was good. The primary was tapped to ring 9. I fed the tripler about 70VAC, 1A. After fooling around for 30 mins solid, with constant on-off-on-off testing, i opened it up and felt the heatsinks. No fans are on, no vents. Mosfets where at 65F, Room temp bright them to 60F before running. The diodes (MUR1560s) on the tripler, 64F. The whole system ran COLD. These mosfets have been working wonders, my IRFP460s usually got hot by now!

If I tap it at 4A, I will get more current ont he arcs. Can i expect larger output? Right now the average was 14"

ScotchTapeLord

Wed May 19 2010, 09:56AM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
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Posts: 635

I believe the laws of solid state coiling say turn it up until things get hot. This is when you put some fans on it, and turn it up until you get too close to the voltage rating of your FETs. Then it's time for full-bridge operation or lower tapping points! =D

I think you should try for performance like that of Anders M.'s beast. (

)

Thank you for doing some tests with those FETs, I was curious to see how they stacked up to their advertised ratings. Though they seem hungry for more than you're giving them... I think you should indulge them. =)

Killa-X

Wed May 19 2010, 01:31PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

About those fets. I sent one to minoritycarrier on the forums to take apart and inspect. To see if they are the real deal :)

ScotchTapeLord

Wed May 19 2010, 02:28PM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
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Posts: 635

If they outperform the tried-and-true 460s, I think it's safe to say they are quite legit. =)
Of course, testing them fully would probably mean being able to cook eggs on your heatsink.

... Hmm...

Killa-X

Sun May 23 2010, 09:10PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

Well, I did a slow break rate, 4 turns on primary, and 450V (no load) set votlage to the capacitors. Using a caliper to compare the length in photo vs the length of an object on photo (in this case the screwdriver mounted as a breakout point) i calculated 14.9 inches, which sounds correct to the picture, since cameras see things a little smaller.

I have to keep it a slow rate else it wants to pull 6-8+ amps, on a 8Amp variac...If i replace the 450V 2200uF overkill capacitors on my tripler to say...200V 1000uF, would I have less amp draw? I feel my variac is pulling so many amps because keeping 3 of those big guys charged is taking a lot of power up.

PICTURES!!!!! I also zapped a metal model BMW :D

The other issue im having, with my audio system, when my hand neass the 2 pots, it changes the sound...when i touch one of the pots, it goes into CW...How can i fix this..?

Killa-X

Sun May 30 2010, 09:45PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

Did the upgrade to a fullbridge. I still have to tune the board, this was just testing "does it actually work?"

Results: (Note, Large topload is 19 inches wide

I really just connected it and let-it-rip. I have 7uF of rectangular brown capacitors on the bridge. I wasn't sure if these had to be Snubbers, So i just have your classic film capacitors.
10uF on the gates, and 0.68uF snubber between the bridge and primary.

Killa-X

Wed Aug 04 2010, 02:04AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

Posting an update on some stuff. Got more to come. I decided to redo my whole base/coil, but still use the same drivers. First, the new case is now acrylic. It will have blue SMD leds pointing down to glow the box. I will be keeping the sides matte, so all the corners glow bright. These are rather bright leds for SMD! As stated earlier, my coil is now fullbridge mode, its last run was hitting 26". I'm redesigning the primary to be a LOT closer, on an acrylic tube. I will enable the ability to run off variac or direct mains, and hope to get more.

People told me in past threads "Those capacitors are WAY too big" for my SSTC...My 4 grey ones. I agree, they were drawing far more amps than what was needed, making it so I couldnt run the coil without drawing over 8A (my variacs limit). I decided to use 9 capacitors for a tripler. They will be parallel for 1410uF instead of 2200uF, I have hopes this will make my coil still perform just as good, but draw less amps to charge such big capacitors.

My bridge is designed to be cubical, so the heatsinks are all facing their own direction, N S E W.

I lost my 4th led...
The blue led isnt even full power and its still so bright :D

I love Acrylic :) Never made a box before, so I enjoyed the looks of it by sticking in my DRSSTC capacitors in it :D

dmg

Wed Aug 04 2010, 08:25PM

Registered Member #2628 Joined: Fri Jan 15 2010, 12:23AM
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Posts: 627

That is a very nice box you made killa, the LEDs really top it off.

Im eager to see the completed system

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