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Pll SSTC- unfinished yet

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LAN_403

Pylon

Tue Apr 13 2010, 06:00PM

Registered Member #2065 Joined: Sun Apr 05 2009, 06:32PM
Location:
Posts: 26

Some time ago i wound secondary and build antena feedback driver same as Steve Ward's mini sstc driver. The sstc isn't working and i dont want to figure out what is the problem so i decided to build a Steve Conner Pll driver. Pll driver works wery well so i want to finish this sstc. I tested it with half-wave rectification, CW mode and audiomodulation works great too :).
Now i going to make new board with AND gate for interrupter input. I going to increase power by decreasing number of turns- now its around 500W but will be much more.
http://www.youtube.com/watch?v=Nemu2clIMHY&feature=channel - audiomodulation test

secondary and primary

CW mode 330uF filtration

Halfbridge

Dr. Dark Current

Tue Apr 13 2010, 07:13PM

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

Nice, but where does the yellow GDT core come from? A PC power supply? (if so I'm surprised it works at all

)

ManiaC

Tue Apr 13 2010, 07:35PM

Registered Member #2763 Joined: Sat Mar 27 2010, 11:48AM
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Posts: 14

big coli and a tinny arc :)

I have a PLL driver and 10-cm coli , the input power is around 150W
and it have a larger arc

I use to interrupt a INH pin on CD4046

GDT look like from PC power supply with a iron core

Pylon

Tue Apr 13 2010, 08:01PM

Registered Member #2065 Joined: Sun Apr 05 2009, 06:32PM
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Posts: 26

I use to interrupt a INH pin on CD4046

Good idea, does it works properly?

This is not core from ATX this it is 3e25 material core, good material for GDT's http://www.ferroxcube.com/prod/assets/3e25.pdf

Yes, arcs are not big now (about 15cm) but this is a first run i have to many turns on primary. For audiomodulation video i made discharges smaller for better audio quality.

Arcstarter

Tue Apr 13 2010, 09:20PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

I always enjoy new sstc threads :D.

I like the secondary and primary, nice job.

But, i do have a few concerns. First of all, the GDT to mosfets should have much smaller leads! That is way too long, at least in my opinion! I normally keep it to an inch or two 'round trip. Another thing, the 10 ohm gate resistor does not need to be that big, and it has to be carbon film or some other film. That one is a ceramic wirewound, and the wire has some inductance. Just a little 1/4 ohm resistor right on the gate should be fine, with the GDT as close as you can possibly get it. There is no need for an entire circuit board for the resistors and zeners, right on the device leads is perfect. Also, try to get the wire on the GDT tighter, so that it is closer to the core. Every little bit reduces leakage inductance!

With a sstc i made, with class E switching, i tested the gate wavefroms with my scope. I tested the waveform right at the ucc3732x, and then an inch away. The ringing was noticeably worse, but completely negligible. Surprisingly, it was the amplitude of the ringing that went up, not the number of cycles... Shorten everything up!

Looking forward to seeing more progress!

Herr Zapp

Tue Apr 13 2010, 09:23PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

Pylon -

You might want to read the Ferroxcube Design Guide for Gate Drive Transformers (

This will help you select the correct core material and winding inductance for your coil's frequency range.

Your 3e25 core material seems to be intended primarily for use in RF noise suppression chokes.

Herr Zapp

Pylon

Tue Apr 13 2010, 10:02PM

Registered Member #2065 Joined: Sun Apr 05 2009, 06:32PM
Location:
Posts: 26

->Herr Zapp
I know that this is not material designed for GDT's but it work very well as GDT (checked with oscilloscope)

->Arcstarter
Yes, this wires are too long

(first i mounted everything on polywood and then i connected everything with wires).
Fortunetely it's works.
For sure my next bridge will be much much beter

(fullbridge i looking for some nice heatsinks)

raff

Wed Apr 14 2010, 04:06AM

Registered Member #2315 Joined: Tue Aug 25 2009, 02:35AM
Location: Leyte, PH
Posts: 161

Pylon wrote ...

->Herr Zapp
I know that this is not material designed for GDT's but it work very well as GDT (checked with oscilloscope)

would very much like to see it in your next bigger/fullbridge SSTC

Pylon

Tue Apr 27 2010, 09:24PM

Registered Member #2065 Joined: Sun Apr 05 2009, 06:32PM
Location:
Posts: 26

Now my sstc waiting for softstart circuit. I have tested CW mode with 1500uF filtering cap- nice hot arc without cracking, that would be nice plasma speaker

.

Some new pics:

Overview

Half-wave discharges

Pylon

Wed Mar 30 2011, 05:15PM

Registered Member #2065 Joined: Sun Apr 05 2009, 06:32PM
Location:
Posts: 26

Hi again

Now my sstc have soft-start circuit, filtering capacitors, and good working audiomodulation.
So i'm going to build final version of sstc driver.

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