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First Half Bridge SSTC , 4046 PLL . :)

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TwirlyWhirly555

Tue Jun 26 2012, 08:34PM

Registered Member #4104 Joined: Fri Sept 23 2011, 06:54PM
Location: Uk .
Posts: 122

Hi ,

Today i built my First ever SSTC :D

The circuit is steve conners PLL Setup , But im using a 1:50 CT as Feedback from secondary but im not fully sure if feedback is working , but its doing something :)

Specks are ;

Arc Ouput under Fullwave supply no smoothing is 7 - 8 " Arcs .

Supply Fullwave 230V .
Primary 10 Turns .
Secondary 4" Diamiter with 6" worth of windings , FreZZ with topload is around 200 Khz .
Half Bridge 500V 16A Mosfets + FreeWheel diode , 30V Zeners on gates , 440V TVS Across each Mosfet .

bridge Capacitors 1uF @ 1Kv .

Gate Driver transformer 8T 1:1:1 . I have scoped the gate signal and it looks good to me no rining and nice flat top and bottoms . 10 Ohm gate resisters .

So all in all its working pritty well heating on mosfets in CW supply is pritty low , with a fan there is no problem what so ever :D and when running smoothed DC supply and audio modulated it sounds great . I Hope Bridge layout is ok too .

next is to build a interrupter for this :) .

audio modulatio smoothed dc supply , me rambling aswell

SAM_0591 by TwirlyWhirly555, on Flickr

SAM_0589 by TwirlyWhirly555, on Flickr

SAM_0592 by TwirlyWhirly555, on Flickr

SAM_0597 by TwirlyWhirly555, on Flickr

SAM_0599 by TwirlyWhirly555, on Flickr

SAM_0603 by TwirlyWhirly555, on Flickr

PhilGood

Tue Jun 26 2012, 09:06PM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

Nice coil, great result (especially for a first try), congrats !

brandon3055

Tue Jun 26 2012, 10:44PM

Registered Member #4548 Joined: Mon Apr 23 2012, 03:52AM
Location: tasmania
Posts: 271

That's graight for a first coil mine only put out 3" streamers but after a lot of tweeting and finding out I built the driver wrong its working a lot better now. Next you need to add a big topload that dobbled the output of mine also another way to increase power is to increase the value of the caps on the bridge
but only if the fets can handle sume extra current both of these modifications increased my streamers from about 5" to about 15" BTW what fets are you using?

TwirlyWhirly555

Wed Jun 27 2012, 08:56AM

Registered Member #4104 Joined: Fri Sept 23 2011, 06:54PM
Location: Uk .
Posts: 122

Destroyer of mosfets wrote ...

That's graight for a first coil mine only put out 3" streamers but after a lot of tweeting and finding out I built the driver wrong its working a lot better now. Next you need to add a big topload that dobbled the output of mine also another way to increase power is to increase the value of the caps on the bridge
but only if the fets can handle sume extra current both of these modifications increased my streamers from about 5" to about 15" BTW what fets are you using?

Thanks :) , When You added a Large Topload i Assume you needed to re addjust driver as Fres Of secondary would have lowerd ? .

Mosfets are IXFH 16N50P i got them as they are cheaper than IRFP450 .

PhillGood : Thanks :)

Dr. Dark Current

Wed Jun 27 2012, 09:38AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Cool, I guess your power input is far beyond 1 kW with those CW arcs

Try a half wave rectification of the mains, you can get longer arcs with much less current draw.

TwirlyWhirly555

Wed Jun 27 2012, 09:52AM

Registered Member #4104 Joined: Fri Sept 23 2011, 06:54PM
Location: Uk .
Posts: 122

Dr. Dark Current wrote ...

Cool, I guess your power input is far beyond 1 kW with those CW arcs

Try a half wave rectification of the mains, you can get longer arcs with much less current draw.

Thanks , heh yeah i can never messure it though as the RF feild messes up my AC Camp meter :P , Okies ill have a try at that :) .

brandon3055

Wed Jun 27 2012, 01:41PM

Registered Member #4548 Joined: Mon Apr 23 2012, 03:52AM
Location: tasmania
Posts: 271

Yes the topload dropped the resinent frez by about 70kHz and mine uses a full bridge of 460's but I have stopped working on it until I can get a scope and build a proper gdt

Steve Conner

Wed Jun 27 2012, 02:25PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Nice, the sparks look great! Maybe the secret of good performance is winding your primary on a plastic bucket.

My Mk1 PLL driver didn't work too well when interrupted. During the interrupter "off" periods, the PLL tended to wander in frequency as it had no signal to lock to.

Also, the feedback never quite worked perfectly, but I thought it was good enough. I got sparks and the FETs didnt overheat.

TwirlyWhirly555

Wed Jun 27 2012, 03:32PM

Registered Member #4104 Joined: Fri Sept 23 2011, 06:54PM
Location: Uk .
Posts: 122

Steve Conner wrote ...

Nice, the sparks look great! Maybe the secret of good performance is winding your primary on a plastic bucket.

Thnaks :D , Id Been looking to build a SSTC for a while and after seeing your circuit i thought id have a go , with CT Feedback aswell .

I Belive the CT is working well and so is the PLL , as when CT is wired Correctly i get great output , i noticed as power is increased to coil there is a sudden jump in output from coil . If the CT is backwards then im lucky if i get 0.5" Arcs :P .

Hmm Ill Keep that in mind as so far i have only 2 Mosfets in my silicon graveyard due to over heating when coil was way way out of tune :D

TwirlyWhirly555

Thu Jun 28 2012, 09:51AM

Registered Member #4104 Joined: Fri Sept 23 2011, 06:54PM
Location: Uk .
Posts: 122

Sorry to doubble post but i have just lot anothere 2 mosfets , after mesuring they both read below 1 ohm between all pins , would this be a over current or over volt of mosfet as heatsink wasnt even close to barly warm ?

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