Developing HV DC Pulses...

  • Thread starter Lamont Cranston
  • Start date
On 22/05/2023 11:51, Lamont Cranston wrote:
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

Is this setup AC or DC, if AC then I wonder if stray capacative coupling
is your problem? Either that or corona?

piglet
 
On Monday, May 22, 2023 at 8:36:40 AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell anything.
¯\\_(ツ)_/¯
I\'m doing the best I can with all your help, which I greatly appreciate.
What we have done so far is getting results, if/when a type of process
is decided on, they can spend money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf
Mikek
 
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

Sorry about that!
Mikek
 
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell anything.
¯\\_(?)_/¯
I\'m doing the best I can with all your help, which I greatly appreciate.
What we have done so far is getting results, if/when a type of process
is decided on, they can spend money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf
Mikek

Corona will be very nonlinear. Crank your Variac down 50% and measure
again.
 
On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. ¯\\_(?)_/¯ I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.

Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. ¯\\_(?)_/¯ I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.


Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs

And with 1 KV per resistor, 8KV total, there shouldn\'t be much corona.

It is interesting how the 1 KV increments aren\'t.
 
On Tuesday, May 23, 2023 at 10:39:49 PM UTC-5, John Larkin wrote:
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. Å»\\_(?)_/Å» I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.


Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs
And with 1 KV per resistor, 8KV total, there shouldn\'t be much corona.

It is interesting how the 1 KV increments aren\'t.

I just ran tests at 8000V, 2000V and 200V output into the divider string.
There are 8 resistors, starting at the low end the calculated numbers
are 12.5%, 25%, 37.5% of the input voltage.
Those three position have the largest errors. The other position are under 2% error (low).

The first position, 32% low (8kV), 32% low (2kV) and 66% low (200V).

The second position, 8.1% low (8kV), 8.9% low (2kV), 24.9% low, (200V).

And the third position, 2.8% low (8kV), 2.1% low (2kV), 6.2% low (200V).

I can\'t explain the odd numbers AT 200v, but, the others make me think there is a
a resistor tolerance adds up to cause the error.
If I get a chance, I\'ll do resistor measurements.
Mikek
 
John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. ¯\\_(?)_/¯ I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.


Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs

And with 1 KV per resistor, 8KV total, there shouldn\'t be much corona.

It is interesting how the 1 KV increments aren\'t.

BITD I did some work on corona point air ionizers for semiconductor clean
rooms. Each point ran at about 2 kV, and put out a few microamps.

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
 
Should I have a concern about radiation from the 6BK4C tube running at 8kV?

The C is a leaded glass tube, but I still wonder if it should have a cage around it.
As I recall the old TVs had a perforated iron cage around them for x-ray protection.
I\'m thinking about a thin wall steel tube as both x-ray and physical protection of the tube.
I\'d leave an open area at the bottom for heat flow up through the tube.
Mikek
P.S. There is some old RCA literature that said during service, replace the 6BK4 with a 6BK4C
to reduce radiation exposure.
 
The resistors are fine , very tight tolerance to each other, the group is 1.6% low.
I went through calculating how much the 100MΩ meter loading affected each reading,
it\'s not responsible for much of the error.
I\'m at a loss. Wasted to much time yesterday trying to figure it out.
I will probably revisit it.
I have enough parts to start building the pulse amp.
Mikek
 
On Friday, May 26, 2023 at 7:40:51 AM UTC-4, Lamont Cranston wrote:
> Should I have a concern about radiation from the 6BK4C tube running at 8kV?

If the tube acts as a switch, it either has low anode bias (when ON) or zero
anode current (when OFF) so no bremstrahllung radiation is expected.
Not in the X-ray energy region, at any rate.
 
On Wed, 24 May 2023 12:24:40 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. ¯\\_(?)_/¯ I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.


Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs

And with 1 KV per resistor, 8KV total, there shouldn\'t be much corona.

It is interesting how the 1 KV increments aren\'t.



BITD I did some work on corona point air ionizers for semiconductor clean
rooms. Each point ran at about 2 kV, and put out a few microamps.

Did they have deliberately super-sharp points and small gaps to create
high field gradients? A resistor soldered to a pair of banana jacks
shouldn\'t do that.
 
On Fri, 26 May 2023 04:40:47 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

> Should I have a concern about radiation from the 6BK4C tube running at 8kV?

No.

The C is a leaded glass tube, but I still wonder if it should have a cage around it.
As I recall the old TVs had a perforated iron cage around them for x-ray protection.
I\'m thinking about a thin wall steel tube as both x-ray and physical protection of the tube.
I\'d leave an open area at the bottom for heat flow up through the tube.
Mikek
P.S. There is some old RCA literature that said during service, replace the 6BK4 with a 6BK4C
to reduce radiation exposure.

At 25 KV, maybe so.
 
John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Wed, 24 May 2023 12:24:40 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. ¯\\_(?)_/¯ I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.


Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs

And with 1 KV per resistor, 8KV total, there shouldn\'t be much corona.

It is interesting how the 1 KV increments aren\'t.



BITD I did some work on corona point air ionizers for semiconductor clean
rooms. Each point ran at about 2 kV, and put out a few microamps.

Did they have deliberately super-sharp points and small gaps to create
high field gradients? A resistor soldered to a pair of banana jacks
shouldn\'t do that.

They’re pointy, but are kept away from other conductors

Corona is a complicated process, with quite different physics depending on
whether the point is positive or negative.

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
 
On Fri, 26 May 2023 16:21:38 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Wed, 24 May 2023 12:24:40 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. ¯\\_(?)_/¯ I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.


Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs

And with 1 KV per resistor, 8KV total, there shouldn\'t be much corona.

It is interesting how the 1 KV increments aren\'t.



BITD I did some work on corona point air ionizers for semiconductor clean
rooms. Each point ran at about 2 kV, and put out a few microamps.

Did they have deliberately super-sharp points and small gaps to create
high field gradients? A resistor soldered to a pair of banana jacks
shouldn\'t do that.



They’re pointy, but are kept away from other conductors

Corona is a complicated process, with quite different physics depending on
whether the point is positive or negative.

I worked with an outfit that made tomographic atom probe microscopes;
we did the electronics. At high fields, like 1e8 v/cm, the field rips
atoms out of a sharp metal tip.

Electron emission from a sharp tip or nanotube has been tried too, as
a tube cold cathode and as an electron microscope source. But the
rip-the-atoms effect dulls the tip pretty soon. Ions are bad news too.

A good field-emission cathode could make a dynamite microwave tube,
sort of a PIN structure but the I part being vacuum.

I wonder if the ionizer tips deteriorate.
 
John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Fri, 26 May 2023 16:21:38 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Wed, 24 May 2023 12:24:40 -0000 (UTC), Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote:
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston
amdx62@gmail.com> wrote:

On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

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)

We turned the lights out last night and could not see or smell
anything. ¯\\_(?)_/¯ I\'m doing the best I can with all your help,
which I greatly appreciate. What we have done so far is getting
results, if/when a type of process is decided on, they can spend
money on something like a Trek 609B-3.
https://www.advancedenergy.com/globalassets/resources-root/data-sheets/en-hv-amplifier-trek-609b-data-sheet.pdf


Mikek

Corona will be very nonlinear. Crank your Variac down 50% and
measure again.


Milliamps of corona should be pretty obvious, I\'d have thought. Dunno
then.

Cheers

Phil Hobbs

And with 1 KV per resistor, 8KV total, there shouldn\'t be much corona.

It is interesting how the 1 KV increments aren\'t.



BITD I did some work on corona point air ionizers for semiconductor clean
rooms. Each point ran at about 2 kV, and put out a few microamps.

Did they have deliberately super-sharp points and small gaps to create
high field gradients? A resistor soldered to a pair of banana jacks
shouldn\'t do that.



They’re pointy, but are kept away from other conductors

Corona is a complicated process, with quite different physics depending on
whether the point is positive or negative.

I worked with an outfit that made tomographic atom probe microscopes;
we did the electronics. At high fields, like 1e8 v/cm, the field rips
atoms out of a sharp metal tip.

Electron emission from a sharp tip or nanotube has been tried too, as
a tube cold cathode and as an electron microscope source. But the
rip-the-atoms effect dulls the tip pretty soon. Ions are bad news too.

Focused ion beam mills use liquid gallium tips. The field pulls the metal
out into an atomically-sharp tip that renews itself continuously.
>

--
Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC /
Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics
 
On Saturday, May 27, 2023 at 3:26:47 AM UTC+10, Phil Hobbs wrote:
John Larkin <jla...@highlandSNIPMEtechnology.com> wrote:
On Fri, 26 May 2023 16:21:38 -0000 (UTC), Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
John Larkin <jla...@highlandSNIPMEtechnology.com> wrote:
On Wed, 24 May 2023 12:24:40 -0000 (UTC), Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
John Larkin <jla...@highlandSNIPMEtechnology.com> wrote:
On Tue, 23 May 2023 22:31:40 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
On 2023-05-22 11:36, John Larkin wrote:
On Mon, 22 May 2023 08:25:12 -0700 (PDT), Lamont Cranston <amd....@gmail.com> wrote:
On Monday, May 22, 2023 at 8:36:40?AM UTC-5, Phil Hobbs wrote:

Electron emission from a sharp tip or nanotube has been tried too, as
a tube cold cathode and as an electron microscope source. But the
rip-the-atoms effect dulls the tip pretty soon. Ions are bad news too.

Focused ion beam mills use liquid gallium tips. The field pulls the metal
out into an atomically-sharp tip that renews itself continuously.

Arc lamps rely on the same mechanism. The tungsten and molybdenum electrodes don\'t melt, but the emitting surface does get hot enough to shape itself into sharp tips under the influences of the local electric field, which is high. The electrodes don\'t last all that long.

Field emission electron microscope sources don\'t last all that long either - ones that run warm do last longer.They do need a very high vacuum at the emitter - as Phil says positive ion bombardment, doesn\'t do them any good at all.

--
Bill Sloman, Sydney
 
I have now hit a point where I think I have a problem where I am putting one side of the neon sign transformer secondary at ground potential.
The scenario is using a sig gen to drive the tube grid, this ties the HV PS at ground (near) potential though the circuit breaker box (sure would be nice to know if the neon transformer could handle that).
I have made a drawing showing in red how the neutral/ground bond causes this to happen.
https://www.dropbox.com/s/kjut0dl8j28q3se/Pulser%20Push-pull%20design.Neutral%20ground%20problem.jpg?dl=0

Can I opto isolate the drive signal from the sig gen to isolate the ground?

Is there another way around this?


Thanks, Mikek
 
On Saturday, May 27, 2023 at 6:55:39 AM UTC-5, Lamont Cranston wrote:
I have now hit a point where I think I have a problem where I am putting one side of the neon sign transformer secondary at ground potential.
The scenario is using a sig gen to drive the tube grid, this ties the HV PS at ground (near) potential though the circuit breaker box (sure would be nice to know if the neon transformer could handle that).
I have made a drawing showing in red how the neutral/ground bond causes this to happen.
https://www.dropbox.com/s/kjut0dl8j28q3se/Pulser%20Push-pull%20design.Neutral%20ground%20problem.jpg?dl=0

Can I opto isolate the drive signal from the sig gen to isolate the ground?

Is there another way around this?


Thanks, Mikek

Does adding an Isolation transformer on the neon sign transformer primary solve the issue?
That would be easy and I have several isolation transformers, that will fit in the HV PS enclosure.
Thanks, Mikek

 
On Sunday, May 28, 2023 at 12:50:14 AM UTC+10, Lamont Cranston wrote:
On Saturday, May 27, 2023 at 6:55:39 AM UTC-5, Lamont Cranston wrote:
I have now hit a point where I think I have a problem where I am putting one side of the neon sign transformer secondary at ground potential.
The scenario is using a sig gen to drive the tube grid, this ties the HV PS at ground (near) potential though the circuit breaker box (sure would be nice to know if the neon transformer could handle that).
I have made a drawing showing in red how the neutral/ground bond causes this to happen.
https://www.dropbox.com/s/kjut0dl8j28q3se/Pulser%20Push-pull%20design.Neutral%20ground%20problem.jpg?dl=0

Can I opto isolate the drive signal from the sig gen to isolate the ground?

Is there another way around this?

Does adding an Isolation transformer on the neon sign transformer primary solve the issue?
That would be easy and I have several isolation transformers, that will fit in the HV PS enclosure.

The neon sign transformer generates rather high voltages across it\'s secondaries. Your isolating transformers may not have been constructed to stand off this kind of voltage.

If you were using the neon sign transformer in the job it was designed for, only the ends of it\'s secondaries would be at a high voltage with respect to ground, but once you start improvising you need a clear picture of which bits are running a long way from ground.

--
Bill Sloman, Sydney
 

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