Developing HV DC Pulses...

[Lamont Cranston]

On Wednesday, May 17, 2023 at 10:12:56 PM UTC-5, whit3rd wrote:

On Wednesday, May 17, 2023 at 4:03:49 AM UTC-7, Lamont Cranston wrote:
On Wednesday, May 17, 2023 at 3:28:31 AM UTC-5, whit3rd wrote:
On Tuesday, May 16, 2023 at 11:10:20 AM UTC-7, Lamont Cranston 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?
No; the insulation between the line windings and the case is probably NOT going to
tolerate kilovolts on the case. And, in case of a wiring fault, the case is a big
chunk of metal that you\'d just as soon wasn\'t hot
That transformer insulation was my concern, I\'d like to know the construction, I\'ll bet there is a lot of spacing between primary and secondary.
The concern I have, though, is between the primary and the case. That might NOT have
been designed or tested for output-voltage levels.
I\'m just looking for a way around these large a exposed aluminum tubes running at HV.
Any Ideas how to do that?
Last resort, I\'ll build a plexiglas or lexan box around them.
Yeah, that\'s about what I\'d do. Maybe two layers, even, with ceramic
standoffs. But, the transformer was designed and potted so the case could be
safely grounded, I\'d use that too.

Referring back to the wiring as it is now, the secondary is floating with no reference to ground.
https://www.dropbox.com/s/bclkcb5oqd13bao/Oil%20water%20Transformer%20wiring.jpg?dl=0
Also the transformer is in a locked plastic case, with no way to physically come in contact wit it.
I don\'t understand how it is safer to have the center tap grounded vs having the secondary floating.
The way I understand it at this point, the reason you can feel (get a shock) is because your body
capacitively couples to complete the circuit. Eurika? Does grounding the center tap halve the
potential you can feel (get shocked).
I don\'t know, I thought it was safer with the secondary floating, just unsure now.
I\'m trying to protect my son, he\'s sharp and more leery of electricity than I am, but running dozens
of 5 minute experiments in a short time, power on / power off repeatedly, it is easy to get complacent!
Add to that, the next set, may be at 1 minute intervals.
Thanks, Mikek

 

[John Walliker]

On Thursday, 18 May 2023 at 04:12:56 UTC+1, whit3rd wrote:

On Wednesday, May 17, 2023 at 4:03:49 AM UTC-7, Lamont Cranston wrote:
On Wednesday, May 17, 2023 at 3:28:31 AM UTC-5, whit3rd wrote:
On Tuesday, May 16, 2023 at 11:10:20 AM UTC-7, Lamont Cranston 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?
No; the insulation between the line windings and the case is probably NOT going to
tolerate kilovolts on the case. And, in case of a wiring fault, the case is a big
chunk of metal that you\'d just as soon wasn\'t hot
That transformer insulation was my concern, I\'d like to know the construction, I\'ll bet there is a lot of spacing between primary and secondary.
The concern I have, though, is between the primary and the case. That might NOT have
been designed or tested for output-voltage levels.
I\'m just looking for a way around these large a exposed aluminum tubes running at HV.
Any Ideas how to do that?
Last resort, I\'ll build a plexiglas or lexan box around them.
Yeah, that\'s about what I\'d do. Maybe two layers, even, with ceramic
standoffs. But, the transformer was designed and potted so the case could be
safely grounded, I\'d use that too.

The case to primary insulation will almost certainly NOT be safe at secondary level
voltages. Why would the designers waste winding space on thicker insulation
where it will never be needed in the intended use?
John

 

[Lamont Cranston]

On Thursday, May 18, 2023 at 5:33:05 AM UTC-5, John Walliker wrote:

The case to primary insulation will almost certainly NOT be safe at secondary level
voltages. Why would the designers waste winding space on thicker insulation
where it will never be needed in the intended use?
John

Seems I need to drop the idea of grounding one side of the secondary.
I\'ll be purchasing plexiglass and solvent to make a physical obstacle
to prevent getting fingers where they shouldn\'t be.
Thanks, Mikek

 

[Lamont Cranston]

On Thursday, May 18, 2023 at 5:40:03 AM UTC-5, Lamont Cranston wrote:

I had placed a bid on a B&K 3011B and did not get it.
I can still get a 3011B, if that is satisfactory.
Is there a Function Generator anyone can recommend that I can use
to Drive the tube?
I\'ll be buying used, probably Ebay to keep the price under $100.
I\'ll probably lend it for the experiments and then keep it for me.

Mikek

 

[Lamont Cranston]

On Thursday, May 18, 2023 at 7:27:32 AM UTC-5, Lamont Cranston wrote:

Dmitry\'s latest Push-Pull Tube Pulse circuit.
https://www.dropbox.com/s/chxbsc2jvsbdu46/Pulser%20Push-pull%20Dmitry%27s%20final%20design..jpg?dl=0
Input welcome.

Thanks, Mikek

 

[John Larkin]

On Thu, 18 May 2023 03:39:59 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Thursday, May 18, 2023 at 5:33:05?AM UTC-5, John Walliker wrote:

The case to primary insulation will almost certainly NOT be safe at secondary level
voltages. Why would the designers waste winding space on thicker insulation
where it will never be needed in the intended use?
John

Seems I need to drop the idea of grounding one side of the secondary.
I\'ll be purchasing plexiglass and solvent to make a physical obstacle
to prevent getting fingers where they shouldn\'t be.
Thanks, Mikek

Ground the transformer case and drive the sample cell differentially.

 

[John Larkin]

On Wed, 17 May 2023 18:14:08 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Wednesday, May 17, 2023 at 8:00:37?PM UTC-5, John Larkin wrote:
On Wed, 17 May 2023 15:07:04 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:
On Wednesday, May 17, 2023 at 4:46:33?PM UTC-5, John Larkin wrote:
On Wed, 17 May 2023 11:00:42 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:
On Wednesday, May 17, 2023 at 12:34:52?PM UTC-5, John Larkin wrote:

The fungen manual said the edges are fast, so it should be terminated or it will ring.

If the gen is a 50 ohm source, that\'s wrong. Loading will cost half
the available voltage swing.

That\'s true, how much voltage swing do I need to drive a 2N7000\"
The manual says, Continuously adjustable from 4 V p-p to 14.5 v p-p, open circuit.
So, a little over 7vpp into 50?. A pair of diagonal cutters will solve it, if it\'s a problem.

If 7v p-p means +-3.5, it\'s not enough.

But don\'t believe me about this stuff.

It has a DC Pulse called a CMOS output.
Schematic of output section.
https://www.dropbox.com/s/1xe4ayjimh92wyk/B%26K%20output.jpg?dl=0

Mikek
The CMOS output circuit is insane.

Not the point John. Will it put out a 7 volt pulse into 50??
Is that enough to saturate the 2N7000.
Here\'s the specifications of the fungen.
https://www.dropbox.com/s/cxfg8aye4pel6sg/B%26K%20specs.jpg?dl=0

I have no idea what your Push pull circuit was, I don\'t have LTspice.
I sent it on to Dmitry, he has modified it, I don\'t know what he did.
Yours to peruse.
https://www.dropbox.com/s/uxwetsrwc9v2lxt/Pulser%20Push%20pull%20as%20Revised%20by%20Dmitry.jpg?dl=0

That doesn\'t make much sense either.

Why do some people insist on putting resistors, and even bypass caps,
across voltage sources in Spice?

 

[Lamont Cranston]

On Thursday, May 18, 2023 at 8:46:16 AM UTC-5, John Larkin wrote:

I have no idea what your Push pull circuit was, I don\'t have LTspice.
I sent it on to Dmitry, he has modified it, I don\'t know what he did.
Yours to peruse.
https://www.dropbox.com/s/uxwetsrwc9v2lxt/Pulser%20Push%20pull%20as%20Revised%20by%20Dmitry.jpg?dl=0
That doesn\'t make much sense either.

Why do some people insist on putting resistors, and even bypass caps,
across voltage sources in Spice?

Is that in the subckt, but not shown in the schematic?
I don\'t see extra resistors or caps in the schematic.
Mikek

 

[John Larkin]

On Thu, 18 May 2023 05:33:20 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Thursday, May 18, 2023 at 7:27:32?AM UTC-5, Lamont Cranston wrote:

Dmitry\'s latest Push-Pull Tube Pulse circuit.
https://www.dropbox.com/s/chxbsc2jvsbdu46/Pulser%20Push-pull%20Dmitry%27s%20final%20design..jpg?dl=0
Input welcome.

Thanks, Mikek

Sure, bipolar grid drive is easy and ideal in Spice. It\'s more work in
real life. Commiting to +-5 may be risky; see the 6BK4 data sheet.

What are R4 and R5 for?

His comments are wrong. For some reason, people get sloppy when they
use Spice. I treat a Spice design like any other engineering document.

 

[John Larkin]

On Thu, 18 May 2023 07:40:31 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Thursday, May 18, 2023 at 8:46:16?AM UTC-5, John Larkin wrote:

I have no idea what your Push pull circuit was, I don\'t have LTspice.
I sent it on to Dmitry, he has modified it, I don\'t know what he did.
Yours to peruse.
https://www.dropbox.com/s/uxwetsrwc9v2lxt/Pulser%20Push%20pull%20as%20Revised%20by%20Dmitry.jpg?dl=0
That doesn\'t make much sense either.

Why do some people insist on putting resistors, and even bypass caps,
across voltage sources in Spice?

Is that in the subckt, but not shown in the schematic?
I don\'t see extra resistors or caps in the schematic.
Mikek

R4. R5. In plain sight.

 

[Anthony William Sloman]

On Thursday, May 18, 2023 at 11:46:16 PM UTC+10, John Larkin wrote:

On Wed, 17 May 2023 18:14:08 -0700 (PDT), Lamont Cranston <amd...@gmail.com> wrote:
On Wednesday, May 17, 2023 at 8:00:37?PM UTC-5, John Larkin wrote:
On Wed, 17 May 2023 15:07:04 -0700 (PDT), Lamont Cranston <amd...@gmail.com> wrote:
On Wednesday, May 17, 2023 at 4:46:33?PM UTC-5, John Larkin wrote:
On Wed, 17 May 2023 11:00:42 -0700 (PDT), Lamont Cranston <amd...@gmail.com> wrote:
On Wednesday, May 17, 2023 at 12:34:52?PM UTC-5, John Larkin wrote:

<snip>

I have no idea what your Push pull circuit was, I don\'t have LTspice.
I sent it on to Dmitry, he has modified it, I don\'t know what he did.
Yours to peruse.
https://www.dropbox.com/s/uxwetsrwc9v2lxt/Pulser%20Push%20pull%20as%20Revised%20by%20Dmitry.jpg?dl=0
That doesn\'t make much sense either.

Why do some people insist on putting resistors, and even bypass caps, across voltage sources in Spice?

That way the LTSpice circuit diagram can look exactly the same as the one that goes into your documentation.

It\'s a waste of time from any other point of view, but designing circuits, and getting them built and documented so they come out exactly as intended can take quite a bit of effort.

And you can put a series resistance into your voltage source. The default seems to be one milliohm.

--
Bill Sloman, Sydney

 

[ehsjr]

On 5/16/2023 9:01 PM, Lamont Cranston wrote:
<snip>

The real problem I have are four 1-3/4\" x 8\" tall aluminum tubes connected to one side of the HV transformer. I want them at ground potential, if possible.
Thanks, Mikek

Can you put the aluminum tubes inside PVC pipe?
Or otherwise make it impossible to touch them while
power is on? For example, the whole mechanism is
inside a box with an interlock, such that when the
box is open power *120VAC) is automatically removed?

Ed

 

[Joe Gwinn]

On Thu, 18 May 2023 17:59:00 -0400, ehsjr <ehsjr@verizon.net> wrote:

On 5/16/2023 9:01 PM, Lamont Cranston wrote:
snip

The real problem I have are four 1-3/4\" x 8\" tall aluminum tubes connected to one side of the HV transformer. I want them at ground potential, if possible.
Thanks, Mikek



Can you put the aluminum tubes inside PVC pipe?
Or otherwise make it impossible to touch them while
power is on? For example, the whole mechanism is
inside a box with an interlock, such that when the
box is open power *120VAC) is automatically removed?

All this is crazy. A neon transformer is not designed to work even
remotely this way. Something bad will happen, and the investigation
will notice that this very much violates the National Electrical Code.
And make sure that your affairs are in order.

Joe Gwinn

 

[Lamont Cranston]

On Thursday, May 18, 2023 at 5:16:33 PM UTC-5, Joe Gwinn wrote:

I’m a little disappointed in the way the voltage divider is working..
Using 1.5MΩ, 2 Watt 5% resistors, 8 in a string.
Setting the input at 8.04kV, we get 7.02Kv, 6.06kV, 5.16kV, 4.28kV, 3.45kV, 2.7kV, and 2.08kV.
When I expected 8KV, 7kV, 6kV, 5kV, 4kV, 3kV, 2kV and 1kV.
Kind of messed up at the bottom end.
Here’s what my voltage divider string looks like on the banana jacks.
Do the think this is caused by leakage across the resistors?
I wiped them down with alcohol and it didn’t get any better.
Using 100MΩ probe.
https://www.dropbox.com/s/eu8hyz676b9moa0/Oil%20water%20High%20Voltage%20diideron%20HV%20banana%20connectors..jpg?dl=0

Mikek

 

[piglet]

On 22/05/2023 04:13, Lamont Cranston wrote:

On Thursday, May 18, 2023 at 5:16:33 PM UTC-5, Joe Gwinn wrote:

I’m a little disappointed in the way the voltage divider is working.
Using 1.5MΩ, 2 Watt 5% resistors, 8 in a string.
Setting the input at 8.04kV, we get 7.02Kv, 6.06kV, 5.16kV, 4.28kV, 3.45kV, 2.7kV, and 2.08kV.
When I expected 8KV, 7kV, 6kV, 5kV, 4kV, 3kV, 2kV and 1kV.
Kind of messed up at the bottom end.
Here’s what my voltage divider string looks like on the banana jacks.
Do the think this is caused by leakage across the resistors?
I wiped them down with alcohol and it didn’t get any better.
Using 100MΩ probe.
https://www.dropbox.com/s/eu8hyz676b9moa0/Oil%20water%20High%20Voltage%20diideron%20HV%20banana%20connectors..jpg?dl=0

Mikek

Puzzling. Have you measured all eight are the same value?

What is the max voltage rating of those resistors, even 2W parts can
have max rating only 500 or 750V - you could try doubling with two
identical in series between each banana jack?

piglet

 

[Lamont Cranston]

On Monday, May 22, 2023 at 2:50:47 AM UTC-5, piglet wrote:

On 22/05/2023 04:13, Lamont Cranston wrote:
On Thursday, May 18, 2023 at 5:16:33 PM UTC-5, Joe Gwinn wrote:

I’m a little disappointed in the way the voltage divider is working.
Using 1.5MΩ, 2 Watt 5% resistors, 8 in a string.
Setting the input at 8.04kV, we get 7.02Kv, 6.06kV, 5.16kV, 4.28kV, 3.45kV, 2.7kV, and 2.08kV.
When I expected 8KV, 7kV, 6kV, 5kV, 4kV, 3kV, 2kV and 1kV.
Kind of messed up at the bottom end.
Here’s what my voltage divider string looks like on the banana jacks.
Do the think this is caused by leakage across the resistors?
I wiped them down with alcohol and it didn’t get any better.
Using 100MΩ probe.
https://www.dropbox.com/s/eu8hyz676b9moa0/Oil%20water%20High%20Voltage%20diideron%20HV%20banana%20connectors..jpg?dl=0

Mikek

Puzzling. Have you measured all eight are the same value?

What is the max voltage rating of those resistors, even 2W parts can
have max rating only 500 or 750V - you could try doubling with two
identical in series between each banana jack?

piglet

I tried a couple of things this morning, I applied the Kapton tape that was bought for this purpose.
That seemed to have a few 10s of volt difference at the low end. under 3%.
But then I noticed where I\'m standing and how the meter leads are dressed makes a difference in the Voltage reading.
I wound the long HV probe cable around the probe and rerouted the low end meter lead.
That improved the last two low end measurement from 2700V to 2130, the expected is 2000V and
2080 down to 1280V, expected 1000V. So, where getting closer to what I expect.
My son is taking the unit back to work to do some experiments today, I will suggest that he shorten
the meter leads to the minimum required to take the measurements.
Thanks, Mikek

 

[John Larkin]

On Mon, 22 May 2023 08:48:41 +0100, piglet <erichpwagner@hotmail.com>
wrote:

On 22/05/2023 04:13, Lamont Cranston wrote:
On Thursday, May 18, 2023 at 5:16:33?PM UTC-5, Joe Gwinn wrote:

I’m a little disappointed in the way the voltage divider is working.
Using 1.5M?, 2 Watt 5% resistors, 8 in a string.
Setting the input at 8.04kV, we get 7.02Kv, 6.06kV, 5.16kV, 4.28kV, 3.45kV, 2.7kV, and 2.08kV.
When I expected 8KV, 7kV, 6kV, 5kV, 4kV, 3kV, 2kV and 1kV.
Kind of messed up at the bottom end.
Here’s what my voltage divider string looks like on the banana jacks.
Do the think this is caused by leakage across the resistors?
I wiped them down with alcohol and it didn’t get any better.
Using 100M? probe.
https://www.dropbox.com/s/eu8hyz676b9moa0/Oil%20water%20High%20Voltage%20diideron%20HV%20banana%20connectors..jpg?dl=0

Mikek


Puzzling. Have you measured all eight are the same value?

What is the max voltage rating of those resistors, even 2W parts can
have max rating only 500 or 750V - you could try doubling with two
identical in series between each banana jack?

piglet

Those don\'t look like 2W resistors, but it\'s hard to tell.

 

[Lamont Cranston]

On Monday, May 22, 2023 at 8:24:35 AM UTC-5, John Larkin wrote:

What is the max voltage rating of those resistors, even 2W parts can
have max rating only 500 or 750V - you could try doubling with two
identical in series between each banana jack?

piglet
Those don\'t look like 2W resistors, but it\'s hard to tell.

2W, 7kV.
https://www.mouser.com/ProductDetail/YAGEO/HHV2SSJT-73-1M5?qs=xZ%2FP%252Ba9zWqZg2GzrHMi14g%3D%3D
Datasheet , https://www.mouser.com/datasheet/2/447/YAGEO_HHV_datasheet_2021v0-3003064.pdf
Thanks, Mikek

 

[Phil Hobbs]

John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:

On Mon, 22 May 2023 08:48:41 +0100, piglet <erichpwagner@hotmail.com
wrote:

On 22/05/2023 04:13, Lamont Cranston wrote:
On Thursday, May 18, 2023 at 5:16:33?PM UTC-5, Joe Gwinn wrote:

I’m a little disappointed in the way the voltage divider is working.
Using 1.5M?, 2 Watt 5% resistors, 8 in a string.
Setting the input at 8.04kV, we get 7.02Kv, 6.06kV, 5.16kV, 4.28kV,
3.45kV, 2.7kV, and 2.08kV.
When I expected 8KV, 7kV, 6kV, 5kV, 4kV, 3kV, 2kV and 1kV.
Kind of messed up at the bottom end.
Here’s what my voltage divider string looks like on the banana jacks.
Do the think this is caused by leakage across the resistors?
I wiped them down with alcohol and it didn’t get any better.
Using 100M? probe.
https://www.dropbox.com/s/eu8hyz676b9moa0/Oil%20water%20High%20Voltage%20diideron%20HV%20banana%20connectors..jpg?dl=0

Mikek


Puzzling. Have you measured all eight are the same value?

What is the max voltage rating of those resistors, even 2W parts can
have max rating only 500 or 750V - you could try doubling with two
identical in series between each banana jack?

piglet

Those don\'t look like 2W resistors, but it\'s hard to tell.

The observation that the tap voltages depend on the position of nearby
conductors is pretty diagnostic of a corona problem.

Cheers

Phil Hobbs
(Who is doubtful of this whole proceeding)

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

 

[Joe Gwinn]

On Sun, 21 May 2023 20:13:54 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Thursday, May 18, 2023 at 5:16:33?PM UTC-5, Joe Gwinn wrote:

I’m a little disappointed in the way the voltage divider is working.
Using 1.5M?, 2 Watt 5% resistors, 8 in a string.
Setting the input at 8.04kV, we get 7.02Kv, 6.06kV, 5.16kV, 4.28kV, 3.45kV, 2.7kV, and 2.08kV.
When I expected 8KV, 7kV, 6kV, 5kV, 4kV, 3kV, 2kV and 1kV.
Kind of messed up at the bottom end.
Here’s what my voltage divider string looks like on the banana jacks.
Do the think this is caused by leakage across the resistors?
I wiped them down with alcohol and it didn’t get any better.
Using 100M? probe.
https://www.dropbox.com/s/eu8hyz676b9moa0/Oil%20water%20High%20Voltage%20diideron%20HV%20banana%20connectors..jpg?dl=0

Mikek

Quoting error. I did not say the above, or anything similar.

Joe Gwinn