Developing HV DC Pulses...

[John Larkin]

On Mon, 15 May 2023 15:56:24 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

>Somewhere in this thread John Larkin suggested a neon bulb to indicate HV is present.

A neon bulb relaxation oscillator would be cool. Just a series
resistor, a cap to ground, and the neon across the cap. It blinks,
faster at higher voltage.

The neon-LDR thing is overkill if all you want to do is drive a remote
LED or something.

I said it probably would be enough of an attention getter.
So, I put a nean tube and an LDR in shrink tube. When the neon tube comes on (about 52Vac)
the LDR drops from 10s of M?s to 7.5k?.
Now my question is,
How do I implement it?
The with the 8 resistor voltage divider, seem we will run at 8KV always. So, I think I can connect
it through a dropping resistor. If I scale the 47K? (120V) to 8kV, that says I need a 3.2M? resistor.

Is that how it should be done?

Then, when we go to a DC filtered supply, I\'m not sure what to do, because we may repeat
some pulsed experiments at lower kVolts. Then the neon bulb wouldn\'t strike. Can I put back to back
100v zeners across the neon bulb and lower the series resistance to the neon bulb, thinking is, it will strike
at lower voltages, but at higher voltages the zeners keep the voltage drop across the neon at a safe level.
I don\'t know what that safe level is.

Here\'s the circuit I put together, please critic. If it needs changes, fine. I thought the base voltage should be a little lower!
https://www.dropbox.com/s/s8pra9x5bdw7dqx/Neon%20tube%20Relay%20Driver.jpg?dl=0

Thanks, Mikek

 

[Lamont Cranston]

On Monday, May 15, 2023 at 9:48:02 PM UTC-5, Anthony William Sloman wrote:

On Tuesday, May 16, 2023 at 9:05:33 AM UTC+10, Lamont Cranston wrote:

I\'m wondering if fast edges are important, can a water bubble move through an emulsion the needed distance as fast as the rise time of a fast pulse!

A water bubble won\'t move fast at all. Your de-emulsifying station will have to move the fluid past the electronces so that there are always a few droplets close to the electrode when the electric field is high enough to move them onto it.
This probably explains why you need a pulsed field - dirt and gunge in the fluid getting de-emulsified will also get stuck to the electrodes and will get stuck tighter than the water droplets. If you turn off the electric field some of the time, the stirring of the fluid will move the gunge away from the electrode far enough to let new water droplets in so that they can coalesce on the electrode when the field comes back.

While I think some coalescence does occur at the electrodes, my understanding from literature is, within the emulsion two bubbles get polarized, there is an attraction between them, they elongate towards each other, and at some point their walls rupture and they combine.
Similar to this,
https://www.dropbox.com/s/p5h1bewz1hkceri/Larger%20Bubble%20forming.jpg?dl=0

Thanks, Mikek

 

[Lamont Cranston]

On Monday, May 15, 2023 at 10:37:50 PM UTC-5, John Larkin wrote:

On Mon, 15 May 2023 15:56:24 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

Somewhere in this thread John Larkin suggested a neon bulb to indicate HV is present.
A neon bulb relaxation oscillator would be cool. Just a series
resistor, a cap to ground, and the neon across the cap. It blinks,
faster at higher voltage.

The neon-LDR thing is overkill if all you want to do is drive a remote
LED or something.

John,
It\'s to easy to get complacent about the voltages when your doing a test every 5 minutes, and soon it may be every 1 minute.
So, I want a big reminder that HV is present. I did twice, the one day I visited the shop.
To that end, this is the blinking red light I have ordered.
https://www.dropbox.com/s/p5h1bewz1hkceri/Larger%20Bubble%20forming.jpg?dl=0
It needs to be an attention getter.
I\'m not sure how 5 parts is overkill, but, I\'d be happy to look at a circuit that will trigger the blinking red led when HV is present.
I have not solved how to keep the neon bulb lit until the voltage drops to 100V, but still work at 9000V.
Maybe just an RC network to extended the time the Red Blinker is on after the neon bulb has extinguished.

Here\'s the circuit I put together, please critic. If it needs changes, fine. I thought the base voltage should be a little lower!
https://www.dropbox.com/s/s8pra9x5bdw7dqx/Neon%20tube%20Relay%20Driver.jpg?dl=0

Mikek

I said it probably would be enough of an attention getter.
So, I put a nean tube and an LDR in shrink tube. When the neon tube comes on (about 52Vac)
the LDR drops from 10s of M?s to 7.5k?.
Now my question is,
How do I implement it?
The with the 8 resistor voltage divider, seem we will run at 8KV always.. So, I think I can connect
it through a dropping resistor. If I scale the 47K? (120V) to 8kV, that says I need a 3.2M? resistor.

Is that how it should be done?

Then, when we go to a DC filtered supply, I\'m not sure what to do, because we may repeat
some pulsed experiments at lower kVolts. Then the neon bulb wouldn\'t strike. Can I put back to back
100v zeners across the neon bulb and lower the series resistance to the neon bulb, thinking is, it will strike
at lower voltages, but at higher voltages the zeners keep the voltage drop across the neon at a safe level.
I don\'t know what that safe level is.

Here\'s the circuit I put together, please critic. If it needs changes, fine. I thought the base voltage should be a little lower!
https://www.dropbox.com/s/s8pra9x5bdw7dqx/Neon%20tube%20Relay%20Driver.jpg?dl=0

Thanks, Mikek

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 5:07:17 AM UTC-5, Lamont Cranston wrote:

Hi John I reported back to the designer of the 6BK4 LTspice subckt, his response is below.
\"I think he probably means the cathode to heater voltage. According to specs, it\'s 400V -ve and not recommended +ve. When output of about 4Kv, cathode has about 200V pulse which is still within heater to cathode voltage as heater is grounded. If not certain always keep the heater floating, grounded via a cap if hums are detected. The cathode can be shunt with suitable resistor for safety reason and to reduce heater to cathode voltage.\"

Also he ran the LTspice with the proposed circuit. I have ask to have C4 removed and to add a 25pf load capacitance.
And also for an output graph, which he didn\'t run.
He also used 1.5MΩ as the pull down resistor, I don\'t know that it needs to be that low.
Here\'s the file as he posted.
https://www.dropbox.com/s/avfsrgmsrnm6wd5/Pulser%20LTspice%206BK4.jpg?dl=0

Thanks, Mikek

 

[John Larkin]

On Tue, 16 May 2023 03:59:58 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Tuesday, May 16, 2023 at 5:07:17?AM UTC-5, Lamont Cranston wrote:

Hi John I reported back to the designer of the 6BK4 LTspice subckt, his response is below.
\"I think he probably means the cathode to heater voltage. According to specs, it\'s 400V -ve and not recommended +ve. When output of about 4Kv, cathode has about 200V pulse which is still within heater to cathode voltage as heater is grounded. If not certain always keep the heater floating, grounded via a cap if hums are detected. The cathode can be shunt with suitable resistor for safety reason and to reduce heater to cathode voltage.\"

Also he ran the LTspice with the proposed circuit. I have ask to have C4 removed and to add a 25pf load capacitance.
And also for an output graph, which he didn\'t run.
He also used 1.5M? as the pull down resistor, I don\'t know that it needs to be that low.
Here\'s the file as he posted.
https://www.dropbox.com/s/avfsrgmsrnm6wd5/Pulser%20LTspice%206BK4.jpg?dl=0

Thanks, Mikek

If the cathode actually pulls itself up to +200, which should be
tested, a small zener to ground would be prudent to protect the
mosfet.

As far as the \"not recommended\" goes, I have based most of my career
on doing not-recommended things. It reduces the competition.

Maybe just a flyback pulser, basically a car ignition thing, would do
the oil separation thing. That would be very simple. The oil drops
won\'t know where the electricity came from.

ps - a little corona never killed anyone.

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 9:21:50 AM UTC-5, John Larkin wrote:

Maybe just a flyback pulser, basically a car ignition thing, would do
the oil separation thing. That would be very simple. The oil drops
won\'t know where the electricity came from.

I\'m not sure how I get a DC pulse, doesn\'t the output of a car ignition ring, A lot!

ps - a little corona never killed anyone.

Yes on corona, at this point I will do simple and better if needed.

I had the LTspicer lower the frequency, he added the 15V zener and a resistor(?).
The latest output is here, such a low frequency the rise and fall times are obscured.
https://www.dropbox.com/s/gkp1nq9jrsqmfz8/Pulser%20LTspice%20low%20frequency.jpg?dl=0

Thanks, Mikek

 

[Anthony William Sloman]

On Wednesday, May 17, 2023 at 12:21:50 AM UTC+10, John Larkin wrote:

On Tue, 16 May 2023 03:59:58 -0700 (PDT), Lamont Cranston <amd...@gmail.com> wrote:
On Tuesday, May 16, 2023 at 5:07:17?AM UTC-5, Lamont Cranston wrote:

<snip>

> As far as the \"not recommended\" goes, I have based most of my career on doing not-recommended things. It reduces the competition.

When it works. You do have to pay some attention to who giving the negative recommendation, and how they justify it.

There are quite a few legacy designers around, and what got recommended when the 555 was new technology isn\'t always what an expert would recommend today.

> Maybe just a flyback pulser, basically a car ignition thing, would do the oil separation thing. That would be very simple. The oil drops won\'t know where the electricity came from.

But they will know if the field isn\'t sustained for long enough to move them around.

> ps - a little corona never killed anyone.

Breathing in too much ozone can take a while to kill you - it may not kill you fast, but emphysema isn\'t a nice way to go.

\"In the air, coronas generate gases such as ozone (O3) and nitric oxide (NO), and in turn, nitrogen dioxide (NO2), and thus nitric acid (HNO3) if water vapor is present. These gases are corrosive and can degrade and embrittle nearby materials, and are also toxic to humans and the environment.\"

It\'s not nice to give advice that can damage people if they take it seriously.

--
Bill Sloman, Sydney

 

[John Larkin]

On Tue, 16 May 2023 07:34:50 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Tuesday, May 16, 2023 at 9:21:50?AM UTC-5, John Larkin wrote:


Maybe just a flyback pulser, basically a car ignition thing, would do
the oil separation thing. That would be very simple. The oil drops
won\'t know where the electricity came from.

I\'m not sure how I get a DC pulse, doesn\'t the output of a car ignition ring, A lot!

Are you sure the oil drops expect a DC pulse?

What does \"DC pulse\" mean anyhow?

ps - a little corona never killed anyone.

Yes on corona, at this point I will do simple and better if needed.

I had the LTspicer lower the frequency, he added the 15V zener and a resistor(?).
The latest output is here, such a low frequency the rise and fall times are obscured.
https://www.dropbox.com/s/gkp1nq9jrsqmfz8/Pulser%20LTspice%20low%20frequency.jpg?dl=0

Thanks, Mikek

Those pulses look pretty nice. 16 volts on the grid does need another
power supply.

What\'s the grid current look like?

I could play with the sim if someone sent me the files.

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 9:57:01 AM UTC-5, Anthony William Sloman wrote:

Breathing in too much ozone can take a while to kill you - it may not kill you fast, but emphysema isn\'t a nice way to go.

It\'s not nice to give advice that can damage people if they take it seriously.

I\'m aware it\'s not good for the human body, I did get a whiff one time, that\'s why I ask about corona mitigation.
Mikek
P.S.
My physicist friend had a pet saying, \"out of an abundance of caution\"

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 10:38:08 AM UTC-5, John Larkin wrote:

What\'s the grid current look like?

I could play with the sim if someone sent me the files.

I have requested the file.

John, I would like to know if I can earth ground one side of the Neon Sign transformer.
Will that cause a stress between the primary and secondary?
https://www.dropbox.com/s/u7nbhwr9rqzpd2l/OiL%20water%20Vessel%20updated.jpg?dl=0

 

[John Larkin]

On Tue, 16 May 2023 09:03:32 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Tuesday, May 16, 2023 at 10:38:08?AM UTC-5, John Larkin wrote:


What\'s the grid current look like?

I could play with the sim if someone sent me the files.

I have requested the file.

John, I would like to know if I can earth ground one side of the Neon Sign transformer.
Will that cause a stress between the primary and secondary?
https://www.dropbox.com/s/u7nbhwr9rqzpd2l/OiL%20water%20Vessel%20updated.jpg?dl=0

Some neon transformers, namely the higher voltage ones, like 16KV,
have two insulated HV terminals. They generally have a secondary
winding whose center tap is already grounded to the case. Ohm it. If
you ground one side of such a transformer, it would be bad news.

The small ones, like 7 KV maybe, usually have a single HV output and
the low side of the secondary is grounded to the case. Again, ohm it.

Modern neons are driven by high frequency supplies. They are small and
cheap compared to the old 60 Hz transformers. I think the neon tubes
look different with high frequency drive, frankly not as pretty.

 

[John Larkin]

On Tue, 16 May 2023 08:46:59 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Tuesday, May 16, 2023 at 9:57:01?AM UTC-5, Anthony William Sloman wrote:

Breathing in too much ozone can take a while to kill you - it may not kill you fast, but emphysema isn\'t a nice way to go.

It\'s not nice to give advice that can damage people if they take it seriously.

I\'m aware it\'s not good for the human body, I did get a whiff one time, that\'s why I ask about corona mitigation.
Mikek
P.S.
My physicist friend had a pet saying, \"out of an abundance of caution\"

I have a saying, \"There are a million ways to not get things done.\"

My first mentor Melvin Goldstein said \"There are a million ways not to
sell.\"

8KV corona is not going to give you emphysema. But it is an abundance
of caution to keep the tip of your nose away from the HV.

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 11:53:08 AM UTC-5, John Larkin wrote:

>If you ground one side of such a transformer, it would be bad news.

I have two 9kV transformers both have a secondary CT. connected to the case..

I have not grounded the case, (as of yet).

If I don\'t ground the case can I then ground one side of the secondary?

Mikek
P.S no word on the LTspice file

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 1:10:20 PM UTC-5, Lamont Cranston wrote:

I sent the 6BK4 asc. file to your work email. I hope that is what you need..
The SUBCKT writer said, if you need anything let me know. So, if you think there is something in the
file that needs correcting he\'s willing to work on it. Apparently, tube subckts are a thing he does
Thanks, Mikek

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 1:48:29 PM UTC-5, Lamont Cranston wrote:

On Tuesday, May 16, 2023 at 1:10:20 PM UTC-5, Lamont Cranston wrote:

I sent the 6BK4 asc. file to your work email. I hope that is what you need.
The SUBCKT writer said, if you need anything let me know. So, if you think there is something in the
file that needs correcting he\'s willing to work on it. Apparently, tube subckts are a thing he does
Thanks, Mikek

Chinese patent (in English) says a lot and tells me nothing, other than, maybe we\'re going in the right direction.
It says ns to ms rise and fall times and 10Hz to 100kHz frequency.
https://patents.google.com/patent/CN101829440A/en

 

[John Larkin]

On Tue, 9 May 2023 05:27:59 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

More oil/water separation.
The AC vs DC separation test was performed and the AC was probably 10 times better. This was a stubborn emulsion, but the AC did work.
( Not throwing DC out yet, need to test other types of oils first.)
Literature says Pulsed DC is best. So to that end, I want to come up with a way to create 500V to 9000V, 1Hz to 1000Hz, HV DC pulses with variable width. Although, I would be satisfied by 1HZ to 100Hz, as literature says a lower frequency is optimum.
The little research I have done shows gated pulses (commercial units) versus a square wave into a step up transformer, and rectifying, I suspect because ringing would be a problem. Looked at old style ignition coil drive circuits, but their wave form is an AC decay signal. Not sure how I could make that a single DC pulse.
I\'m looking at the simple 555 to create the variable pulse, but after that I\'m not sure how to get a decent variable HV DC pulse.
Any ideas to help me are appreciated,
Thanks, Mikek
P.S. We are using a variac driving a neon sign transformer for variable AC voltage and then full wave bridge to get variable DC voltage.
Still waiting on a capacitance and parallel resistance of the test vessel with and without solution.

Here\'s a tube pulser:

https://www.dropbox.com/s/esci7na1lbpa82s/Tube_Pulser_JL_1.zip?dl=0

 

[John Larkin]

On Tue, 16 May 2023 11:10:15 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Tuesday, May 16, 2023 at 11:53:08?AM UTC-5, John Larkin wrote:

If you ground one side of such a transformer, it would be bad news.

I have two 9kV transformers both have a secondary CT. connected to the case.

I have not grounded the case, (as of yet).

If I don\'t ground the case can I then ground one side of the secondary?

That would make the case kilovolts live to ground, potentially deadly.

Ground the case and use one side. If you need more voltage, use a
doubler or a c-w stack.

 

[John Larkin]

On Tue, 16 May 2023 11:48:25 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Tuesday, May 16, 2023 at 1:10:20?PM UTC-5, Lamont Cranston wrote:

I sent the 6BK4 asc. file to your work email. I hope that is what you need.
The SUBCKT writer said, if you need anything let me know. So, if you think there is something in the
file that needs correcting he\'s willing to work on it. Apparently, tube subckts are a thing he does
Thanks, Mikek

Got it, tweaked it, posted below.

 

[Lamont Cranston]

On Tuesday, May 16, 2023 at 6:10:19 PM UTC-5, John Larkin wrote:

On Tue, 16 May 2023 11:48:25 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:
On Tuesday, May 16, 2023 at 1:10:20?PM UTC-5, Lamont Cranston wrote:

I sent the 6BK4 asc. file to your work email. I hope that is what you need.
The SUBCKT writer said, if you need anything let me know. So, if you think there is something in the
file that needs correcting he\'s willing to work on it. Apparently, tube subckts are a thing he does
Thanks, Mikek
Got it, tweaked it, posted below.

Does that mean I need 24V to drive the grid?
Does that mean I need a 60V power supply?
I can do that, just want to know if that\'s what the circuit diagram means.
Mikek

 

[John Larkin]

On Tue, 16 May 2023 16:36:19 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Tuesday, May 16, 2023 at 6:10:19?PM UTC-5, John Larkin wrote:
On Tue, 16 May 2023 11:48:25 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:
On Tuesday, May 16, 2023 at 1:10:20?PM UTC-5, Lamont Cranston wrote:

I sent the 6BK4 asc. file to your work email. I hope that is what you need.
The SUBCKT writer said, if you need anything let me know. So, if you think there is something in the
file that needs correcting he\'s willing to work on it. Apparently, tube subckts are a thing he does
Thanks, Mikek
Got it, tweaked it, posted below.

Does that mean I need 24V to drive the grid?
Does that mean I need a 60V power supply?
I can do that, just want to know if that\'s what the circuit diagram means.
Mikek

It seems to work well with +24 on the grid. The tube turns on hard and
the pulsed grid current is about 25 mA. I assume Dmitry\'s model
handles the positive grid case about right.

Turns out you can use a 50 volt zener from the cathode to ground,
instead of the diode+power supply.

Run the sim and tweak!

It might be a tad different in real life, with a filament connected.