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Pulse Skipped DRSSTC Waveform

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Chris_Dickey

Tue Dec 06 2016, 09:40PM

Registered Member #61302 Joined: Mon Nov 21 2016, 03:09AM
Location:
Posts: 4

Hi all,

I've been playing with freewheeling since about May of last year (with Steve's UD3), and I can confirm seeing exactly what julian just posted. The main difference is that I've been achieving upper pole oscillation by means of a startup oscillator, instead of retuning. I always use upper pole operation now, because it produces bigger sparks on this coil.

As-built, the primary alone resonates at 200kHz (with no secondary). I drive the primary at 238kHz for 6 cycles at the beginning of each burst (experimentally determined). Over the course of the burst, the primary resonant frequency drops to 200kHz and stays there. It only takes about 800us to drop to 200kHz, and I run a max of about 6ms.

I have a variety of scope captures and videos, albeit not very organized. I will do what I can to make this sensical. This did not happen in a day; I explored in several-day bursts over the course of a year, hence the different settings and scopes.

Lower pole; "mushroom" waveform:

Full video:

Upper pole; not full bus voltage, high current limit (never hits the limiter):

Upper pole, ground strike; same bus voltage, same limiter:

Full video:

Upper pole, higher bus voltage, higher resolution scope:

If anyone is interested in seeing how deep the rabbit hole goes, I'll organize more info about all of this.

Edit: fixed YouTube embeds

zzz_julian_zzz

Fri Dec 30 2016, 03:41PM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

Hi All,

Just to give you update on this project..

will improve it for sure :)
thanks!

Julian

zzz_julian_zzz

Thu Jan 05 2017, 02:38PM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

Hi All,

just want to show the assembly photos of this project.. My 5ft arc output goal for Pulse Skipped DRSSTC is already exceeded.. Arc now is reaching 6ft (ceiling) @4ms, 600 Amp, 35 bps ; and I believe it can go further if pulse length, OCD level, and BPS are increased but I don't want to see that anymore. That AC main wall socket in my house where I use for TC operation is only limited to 20 Amps (dedicated CB).. My Pulse Skip TC has its own 15 Ampere CB in it, and more than the above parameters and it trips..

Thanks to Hydron, Phillips and Chris for the help!

Julian

futurist

Tue Mar 21 2017, 03:14PM

Registered Member #61400 Joined: Sun Jan 01 2017, 01:01PM
Location:
Posts: 33

Good work on the coil!

How did you manage to get the coil running at upper pole without using a startup oscilator?

Hydron

Tue Mar 21 2017, 05:14PM

Registered Member #30656 Joined: Tue Jul 30 2013, 02:40AM
Location: UK
Posts: 208

I suspect that he tuned the primary high enough to make the upper pole gain greater than the lower pole - as far as I know this is the only way to do it without a startup oscillator based driver.

If you have the tuning range then give it a try - it may run better or worse than at the lower pole. I ended up running my big coil at upper pole for more "controlled" sparks, especially when playing MIDI. Before I upgraded to a voltage-doubler rectifier on the mains input I ran it at lower pole for lower primary impedance and bigger sparks with the limited voltage I had to play with.

zzz_julian_zzz

Mon Mar 27 2017, 01:57PM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

futurist wrote ...

Good work on the coil!

How did you manage to get the coil running at upper pole without using a startup oscilator?

Hi Futurist,

Thanks for your interest.. first thing I just want to clarify, I am doing LOWER POLE mode of operation. It is posted/specs of the coil above... It gives the coil the thickness / intensity of sparks.. In my QCW (buck controlled), i operate in upper pole - sparks are long ~6ft and easily controlled BUT not as "intense" in terms of spark appearance vs a LOW POLE operation. In QCW -SWORD spark likeness, I needed to operate in UPPER because of control, but in my PULSE SKIP, I use lower pole simply because I want the spark to explode /express and less of containment.

My circuit (driver of my first pulse skip coil) is basically an "all analogue circuitry" nothing great in there, just a bunch of chips - reason is simplicity and because I don't know how to CLPD or FPGA

My pulse skip is doing ~5ft and I cannot go further(<4ms) due to limited power source / our house's CB is tripping and causing local brownouts. :) so I had to stop..

futurist

Mon Mar 27 2017, 08:14PM

Registered Member #61400 Joined: Sun Jan 01 2017, 01:01PM
Location:
Posts: 33

I thought that with the pulse skipping and running at lower pole the coil would detune itself so much that you couldn't get streamers that long

zzz_julian_zzz

Tue Mar 28 2017, 10:23AM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

futurist wrote ...

I thought that with the pulse skipping and running at lower pole the coil would detune itself so much that you couldn't get streamers that long

Could be for some cases, but not based on what I saw from my attempt

Intra

Mon Sept 11 2017, 10:07AM

Registered Member #2694 Joined: Mon Feb 22 2010, 11:52PM
Location: Russia, Volgograd (Stalingrad).
Posts: 97

zzz_julian_zzz wrote ...

Hi All,

Just to give you update on this project..

will improve it for sure :)
thanks!

Julian

Hi Julian,
Is this coil loud as QCW or as DRSSTC?

zzz_julian_zzz

Sun Sept 17 2017, 02:25AM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

Intra wrote ...

zzz_julian_zzz wrote ...

Hi All,

Just to give you update on this project..

will improve it for sure :)
thanks!

Julian

Hi Julian,
Is this coil loud as QCW or as DRSSTC?

Qcw is very silent type of coil..(if power source is tuned correctly - with smooth ramp down too)
Pulse Skip is different. It is a Drsstc sounding with ~50 bps or so but with more thickness in it(~4ms) so the sound is like angry drsstc.. loud and scary..

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