HV insulation test

On Sun, 13 Oct 2019 15:56:20 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

DecadentLinuxUserNumeroUno@decadence.org wrote in news:qnvgc3$1pb6$1
@gioia.aioe.org:

jlarkin@highlandsniptechnology.com wrote in
news:7qf6qehdu80qhhe45vr1bt4sh4p6icjemj@4ax.com:

On 13 Oct 2019 06:59:39 -0700, Winfield Hill
winfieldhill@yahoo.com
wrote:

jlarkin@highlandsniptechnology.com wrote...

Crank the voltage up until it arcs.

Then I'd have to throw it away. I finished
the SHV cable at the end of work Friday, and
took home a 5kV supply. Tuesday I'll push to
higher voltages, thinking of stopping at 10kV.

I need to rebuild the SHV cable, forgot to
flair the shield away from the RG-58/U center
dielectric, before soldering a ground wire.

I was thinking that you could make a HV transformer by

Winding a ferrite toroid with a few turns of well-insulated wire,
maybe HV wire on secondary only

Place Nomex™ transformer paper on the core center.

It is 715 V/mil dielectric strength.

Double strength transformer wire has more. Some makers go up to
quad strength.

But I found the ultimate HV wire...

https://www.zeusinc.com/products/insulated-wire/peek-insulated-
wire/


WOW! 500 degrees! 25kV!


or

Separating the halves of a pot core with a sheet of really good
insulator.

Not good. That gap has efficiency costs.

It adds a bit of leakage inductance, but can still transfer lots of
power. Resonate both windings.

You could also make a capacitive or inductive coupler as a PC
board.
Maybe use unshielded surface-mount drum core inductors on opposite
sides.

Two drums, same side, Nomex paper separator. Still need a good core
in there.

I was thinking opposite sides, no added core, resonate the inductors.
Rotate one 90 degrees about the common axis so their pads don't align.

Same side has PCB surface leakage/tracking hazards.

I designed an electric meter that could be read if the line power was
off, for a country with unreliable power. I transferred about 100 mW
over an inch gap with resonated ferrite bar inductors. Sent the data
over the same link.





--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Martin Riddle]

On Sun, 13 Oct 2019 08:20:29 -0700, jlarkin@highlandsniptechnology.com
wrote:

On 13 Oct 2019 06:59:39 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

jlarkin@highlandsniptechnology.com wrote...

Crank the voltage up until it arcs.

Then I'd have to throw it away. I finished
the SHV cable at the end of work Friday, and
took home a 5kV supply. Tuesday I'll push to
higher voltages, thinking of stopping at 10kV.

I need to rebuild the SHV cable, forgot to
flair the shield away from the RG-58/U center
dielectric, before soldering a ground wire.

I was thinking that you could make a HV transformer by

Winding a ferrite toroid with a few turns of well-insulated wire,
maybe HV wire on secondary only

snip

Yep, works. I have seen this done.

Cheers

 

On Sun, 13 Oct 2019 15:02:29 -0400, Martin Riddle
<martin_ridd@verizon.net> wrote:

On Sun, 13 Oct 2019 08:20:29 -0700, jlarkin@highlandsniptechnology.com
wrote:

On 13 Oct 2019 06:59:39 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

jlarkin@highlandsniptechnology.com wrote...

Crank the voltage up until it arcs.

Then I'd have to throw it away. I finished
the SHV cable at the end of work Friday, and
took home a 5kV supply. Tuesday I'll push to
higher voltages, thinking of stopping at 10kV.

I need to rebuild the SHV cable, forgot to
flair the shield away from the RG-58/U center
dielectric, before soldering a ground wire.

I was thinking that you could make a HV transformer by

Winding a ferrite toroid with a few turns of well-insulated wire,
maybe HV wire on secondary only

snip

Yep, works. I have seen this done.

Cheers

A single-turn secondary could be enough in some applications. Add a
small step-up transformer or a series LC on the high side if the
voltage is too low.

60 Hz transformers get around 1 volt per turn. High frequency ones can
be a lot more.




--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High frequency ones
can be a lot more.

Not a great idea though. Ideally one wants to keep the volts per
turn pretty low. 1 or 2 volts is good. If it climbs up too much a lot
of other considerations have to start being made.

 

[Michael Terrell]

On Sunday, October 13, 2019 at 11:23:42 AM UTC-4, Winfield Hill wrote:

Michael Terrell wrote...

Are you familiar with HV putty?

https://www.newark.com/gc-electronics/10-8880/high-voltage-silicon-putty-1-25/dp/33K4548

No, I wasn't, thanks!!

I used it 40+ years ago on some TVs that had cracks in the molded plastic parts in the HV supply that couldn't be replaced. It stopped them from producing Ozone. It didn't dry out, and properly applied, I've never heard of it failing.

 

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High frequency ones
can be a lot more.



Not a great idea though. Ideally one wants to keep the volts per
turn pretty low. 1 or 2 volts is good. If it climbs up too much a lot
of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10 or 20
volts from a 1-turn secondary would be easy. Or more.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High frequency
ones can be a lot more.



Not a great idea though. Ideally one wants to keep the volts
per
turn pretty low. 1 or 2 volts is good. If it climbs up too much
a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10 or
20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most cases.
It is, of course a direct ratio to the primary turns count.

Step up secondaries, in particular, should not have that high a volts
per turn number. Mag wire insulation matters and turns at the end of
a winding getting near turns at the start will result in a fail...
often.

 

[John Larkin]

On Mon, 14 Oct 2019 03:10:09 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High frequency
ones can be a lot more.



Not a great idea though. Ideally one wants to keep the volts
per
turn pretty low. 1 or 2 volts is good. If it climbs up too much
a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10 or
20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most cases.
It is, of course a direct ratio to the primary turns count.

The primary could be one turn too. Or series resonate the primary to
get a lot of voltage. Or just apply a lot of voltage.

Step up secondaries, in particular, should not have that high a volts
per turn number. Mag wire insulation matters and turns at the end of
a winding getting near turns at the start will result in a fail...
often.

It's not volts per turn that will make the secondary ends arc... it's
pure volts.

Total one turn of 30KV-insulated wire fixes that problem.

 

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:jad9qeht8tgq73j693n5d5sjq69rak9pfb@4ax.com:

On Mon, 14 Oct 2019 03:10:09 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High frequency
ones can be a lot more.



Not a great idea though. Ideally one wants to keep the volts
per
turn pretty low. 1 or 2 volts is good. If it climbs up too
much a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10 or
20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most
cases.
It is, of course a direct ratio to the primary turns count.

The primary could be one turn too. Or series resonate the primary
to get a lot of voltage. Or just apply a lot of voltage.


Step up secondaries, in particular, should not have that high a
volts per turn number. Mag wire insulation matters and turns at
the end of a winding getting near turns at the start will result
in a fail... often.

It's not volts per turn that will make the secondary ends arc...
it's pure volts.

Total one turn of 30KV-insulated wire fixes that problem.

You don't get it. A 1500 turn secondary has to have the turn
managed such that NO earlier turns get anywhere near ANY upper count
turns. 1500 turns of #43, not your impossible insulated wire
application. So the volts per turn add up. Too high and the
transfomer incessanlty arcs and fails 3 out of 4 builds. Reduce the
volts per turn to 1.5 or less and the transformer works, without
failure, unpotted. And that is at 58kHz.

But you also have to be smart enough to know how to build an HV
transformer with 1500 turns on the secondary that operates unpotted.
You cannot simply 'scatter wind' it. It is not merely about the
separation of the end nodes of the winding, the turns also have to be
kept away from the younger bretheren. 1500 turns was 10 150 turn
layers with a 1 mil transformer tape layer between each.

You are not going to get 30kV from one turn. And you would never
need 30kV insulated wire on asmall form factor transformer. They
likely do not use it in the larger form factor power realm either.
The insulation takes up too much space, and usually has thermal
issues since the insulation insulates. That is why they too have
polymide coated mag wire in use.

 

[Martin Riddle]

On Mon, 14 Oct 2019 14:50:18 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

On Mon, 14 Oct 2019 18:35:55 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:jad9qeht8tgq73j693n5d5sjq69rak9pfb@4ax.com:

On Mon, 14 Oct 2019 03:10:09 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High frequency
ones can be a lot more.



Not a great idea though. Ideally one wants to keep the volts
per
turn pretty low. 1 or 2 volts is good. If it climbs up too
much a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10 or
20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most
cases.
It is, of course a direct ratio to the primary turns count.

The primary could be one turn too. Or series resonate the primary
to get a lot of voltage. Or just apply a lot of voltage.


Step up secondaries, in particular, should not have that high a
volts per turn number. Mag wire insulation matters and turns at
the end of a winding getting near turns at the start will result
in a fail... often.

It's not volts per turn that will make the secondary ends arc...
it's pure volts.

Total one turn of 30KV-insulated wire fixes that problem.


You don't get it. A 1500 turn secondary has to have the turn
managed such that NO earlier turns get anywhere near ANY upper count
turns. 1500 turns of #43, not your impossible insulated wire
application. So the volts per turn add up. Too high and the
transfomer incessanlty arcs and fails 3 out of 4 builds. Reduce the
volts per turn to 1.5 or less and the transformer works, without
failure, unpotted. And that is at 58kHz.

But you also have to be smart enough to know how to build an HV
transformer with 1500 turns on the secondary that operates unpotted.
You cannot simply 'scatter wind' it. It is not merely about the
separation of the end nodes of the winding, the turns also have to be
kept away from the younger bretheren. 1500 turns was 10 150 turn
layers with a 1 mil transformer tape layer between each.

You are not going to get 30kV from one turn.

The problem under discussion is powering a bit of gear that's sitting
way off ground. So one secondary turn has to make a few volts out but
be *insulated* for kilovolts.

It's sure easy to wind a 1-turn winding.

I think he's getting at turns per layer. HV tranformers usually have a
tall stack of layers a few turns each. Then thers capacitance to worry
about.

Cheers

 

[John Larkin]

On Mon, 14 Oct 2019 18:35:55 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:jad9qeht8tgq73j693n5d5sjq69rak9pfb@4ax.com:

On Mon, 14 Oct 2019 03:10:09 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High frequency
ones can be a lot more.



Not a great idea though. Ideally one wants to keep the volts
per
turn pretty low. 1 or 2 volts is good. If it climbs up too
much a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10 or
20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most
cases.
It is, of course a direct ratio to the primary turns count.

The primary could be one turn too. Or series resonate the primary
to get a lot of voltage. Or just apply a lot of voltage.


Step up secondaries, in particular, should not have that high a
volts per turn number. Mag wire insulation matters and turns at
the end of a winding getting near turns at the start will result
in a fail... often.

It's not volts per turn that will make the secondary ends arc...
it's pure volts.

Total one turn of 30KV-insulated wire fixes that problem.


You don't get it. A 1500 turn secondary has to have the turn
managed such that NO earlier turns get anywhere near ANY upper count
turns. 1500 turns of #43, not your impossible insulated wire
application. So the volts per turn add up. Too high and the
transfomer incessanlty arcs and fails 3 out of 4 builds. Reduce the
volts per turn to 1.5 or less and the transformer works, without
failure, unpotted. And that is at 58kHz.

But you also have to be smart enough to know how to build an HV
transformer with 1500 turns on the secondary that operates unpotted.
You cannot simply 'scatter wind' it. It is not merely about the
separation of the end nodes of the winding, the turns also have to be
kept away from the younger bretheren. 1500 turns was 10 150 turn
layers with a 1 mil transformer tape layer between each.

You are not going to get 30kV from one turn.

The problem under discussion is powering a bit of gear that's sitting
way off ground. So one secondary turn has to make a few volts out but
be *insulated* for kilovolts.

It's sure easy to wind a 1-turn winding.

 

Martin Riddle <martin_ridd@verizon.net> wrote in
news:ust9qedbee9sql0mb4uejnf8p6f76o7v0o@4ax.com:

On Mon, 14 Oct 2019 14:50:18 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:

On Mon, 14 Oct 2019 18:35:55 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:jad9qeht8tgq73j693n5d5sjq69rak9pfb@4ax.com:

On Mon, 14 Oct 2019 03:10:09 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High
frequency ones can be a lot more.



Not a great idea though. Ideally one wants to keep the
volts per
turn pretty low. 1 or 2 volts is good. If it climbs up too
much a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10
or 20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most
cases.
It is, of course a direct ratio to the primary turns count.

The primary could be one turn too. Or series resonate the
primary to get a lot of voltage. Or just apply a lot of
voltage.


Step up secondaries, in particular, should not have that high a
volts per turn number. Mag wire insulation matters and turns
at the end of a winding getting near turns at the start will
result in a fail... often.

It's not volts per turn that will make the secondary ends
arc... it's pure volts.

Total one turn of 30KV-insulated wire fixes that problem.


You don't get it. A 1500 turn secondary has to have the turn
managed such that NO earlier turns get anywhere near ANY upper
count turns. 1500 turns of #43, not your impossible insulated
wire application. So the volts per turn add up. Too high and
the transfomer incessanlty arcs and fails 3 out of 4 builds.
Reduce the volts per turn to 1.5 or less and the transformer
works, without failure, unpotted. And that is at 58kHz.

But you also have to be smart enough to know how to build an HV
transformer with 1500 turns on the secondary that operates
unpotted. You cannot simply 'scatter wind' it. It is not merely
about the separation of the end nodes of the winding, the turns
also have to be kept away from the younger bretheren. 1500 turns
was 10 150 turn layers with a 1 mil transformer tape layer
between each.

You are not going to get 30kV from one turn.

The problem under discussion is powering a bit of gear that's
sitting way off ground. So one secondary turn has to make a few
volts out but be *insulated* for kilovolts.

It's sure easy to wind a 1-turn winding.

I think he's getting at turns per layer. HV tranformers usually
have a tall stack of layers a few turns each. Then thers
capacitance to worry about.

Cheers

Winding to winding capacitance, sure, but not interwinding
capacitance.

But no. I know what was being discussed and I know what volts per
turn are.

You obviously do not simply because you attempted to "tell what I
was talking about".

The winding is layers so that early turns do not come into
proximity with later turns. Do the math. 1500 turns at 1 volt per
turn means I can put about 150 turns on each layer before the mag
wire insulation strength is approached. What you cannot do is allow
any of those early layer conductors to get close to later ones. The
layers even start inboard so that the layer egdes do not have exposed
turns and none "fall down" to lower layers while you wind. Both
result in a fail.

TAPE
^_________
-------
^wire turns


They are 'flat wound' (one layer of turns) so the layer stack is
not that great, and the primary goes on the outside. That is the
example I was describing. 10 stacks of 150 turns is 1500.

A linear segmented transformer bobbin is similar in that each
segment holds some wire, then the winding steps over to the next
segment and continues. This is done to limit the number of turns per
segment so that first turns do not get near later turns.

If you have never tested or examined transformers in failure and
documented failure modes, you may not understand that the first turn
is lots of volts separated from the last when there are lots of turns
to speak of.

But yeah, I got his post where he is talking about a single turn.

 

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:66r9qedlr0gj5k7q0uisvgc9pkr91rhp70@4ax.com:

On Mon, 14 Oct 2019 18:35:55 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:jad9qeht8tgq73j693n5d5sjq69rak9pfb@4ax.com:

On Mon, 14 Oct 2019 03:10:09 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High
frequency ones can be a lot more.



Not a great idea though. Ideally one wants to keep the
volts per
turn pretty low. 1 or 2 volts is good. If it climbs up too
much a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10
or 20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most
cases.
It is, of course a direct ratio to the primary turns count.

The primary could be one turn too. Or series resonate the
primary to get a lot of voltage. Or just apply a lot of voltage.


Step up secondaries, in particular, should not have that high a
volts per turn number. Mag wire insulation matters and turns at
the end of a winding getting near turns at the start will result
in a fail... often.

It's not volts per turn that will make the secondary ends arc...
it's pure volts.

Total one turn of 30KV-insulated wire fixes that problem.


You don't get it. A 1500 turn secondary has to have the turn
managed such that NO earlier turns get anywhere near ANY upper
count turns. 1500 turns of #43, not your impossible insulated
wire application. So the volts per turn add up. Too high and the
transfomer incessanlty arcs and fails 3 out of 4 builds. Reduce
the volts per turn to 1.5 or less and the transformer works,
without failure, unpotted. And that is at 58kHz.

But you also have to be smart enough to know how to build an HV
transformer with 1500 turns on the secondary that operates
unpotted. You cannot simply 'scatter wind' it. It is not merely
about the separation of the end nodes of the winding, the turns
also have to be kept away from the younger bretheren. 1500 turns
was 10 150 turn layers with a 1 mil transformer tape layer between
each.

You are not going to get 30kV from one turn.

The problem under discussion is powering a bit of gear that's
sitting way off ground. So one secondary turn has to make a few
volts out but be *insulated* for kilovolts.

It's sure easy to wind a 1-turn winding.

Just use two turns or three or four. Use the insulated wire, sure,
but you'll get better core couple from a few spaced turns. Also
'powering a bit of gear' from one turn?

 

On Tue, 15 Oct 2019 00:03:20 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:66r9qedlr0gj5k7q0uisvgc9pkr91rhp70@4ax.com:

On Mon, 14 Oct 2019 18:35:55 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:jad9qeht8tgq73j693n5d5sjq69rak9pfb@4ax.com:

On Mon, 14 Oct 2019 03:10:09 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:u2p7qe95pid7dkr5j3l4n1nel5ttg0kv9k@4ax.com:

On Sun, 13 Oct 2019 23:20:08 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:aav6qede9htv40ceu3sj7rp8gvttdshvp5@4ax.com:

60 Hz transformers get around 1 volt per turn. High
frequency ones can be a lot more.



Not a great idea though. Ideally one wants to keep the
volts per
turn pretty low. 1 or 2 volts is good. If it climbs up too
much a lot of other considerations have to start being made.

Volts per turn is pretty much linear on frequency. Getting 10
or 20 volts from a 1-turn secondary would be easy. Or more.

A 'one turn secondary' would be a serious step DOWN in most
cases.
It is, of course a direct ratio to the primary turns count.

The primary could be one turn too. Or series resonate the
primary to get a lot of voltage. Or just apply a lot of voltage.


Step up secondaries, in particular, should not have that high a
volts per turn number. Mag wire insulation matters and turns at
the end of a winding getting near turns at the start will result
in a fail... often.

It's not volts per turn that will make the secondary ends arc...
it's pure volts.

Total one turn of 30KV-insulated wire fixes that problem.


You don't get it. A 1500 turn secondary has to have the turn
managed such that NO earlier turns get anywhere near ANY upper
count turns. 1500 turns of #43, not your impossible insulated
wire application. So the volts per turn add up. Too high and the
transfomer incessanlty arcs and fails 3 out of 4 builds. Reduce
the volts per turn to 1.5 or less and the transformer works,
without failure, unpotted. And that is at 58kHz.

But you also have to be smart enough to know how to build an HV
transformer with 1500 turns on the secondary that operates
unpotted. You cannot simply 'scatter wind' it. It is not merely
about the separation of the end nodes of the winding, the turns
also have to be kept away from the younger bretheren. 1500 turns
was 10 150 turn layers with a 1 mil transformer tape layer between
each.

You are not going to get 30kV from one turn.

The problem under discussion is powering a bit of gear that's
sitting way off ground. So one secondary turn has to make a few
volts out but be *insulated* for kilovolts.

It's sure easy to wind a 1-turn winding.



Just use two turns or three or four. Use the insulated wire, sure,
but you'll get better core couple from a few spaced turns. Also
'powering a bit of gear' from one turn?

Win wanted a couple hundred milliwatts to power a DVM module, some
kilovolts off ground.

That should be possible from one turn of something like spark plug
wire.

Yikes, this is claimed to be good for 50 KV:

https://www.digikey.com/product-detail/en/daburn-electronics/CRT26-10BK-100/CRT26-10BK-100-ND/322621

and OD is 0.213". 2 or 3 turns of that would be windable, but one
would be fun.

Or 30KV at 100 mils OD

https://www.digikey.com/product-detail/en/daburn-electronics/2475-20B-YL-1000/2475-20BYL-1000-ND/5246891


There's some 20KV stuff that's 50 mils OD. Make several turns! In a
pot core maybe.







--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Winfield Hill]

DecadentLinuxUserNumeroUno@decadence.org wrote...

But yeah, I got his post where he is talking about a single turn.

Single turn, smingle turn. OK, consider my single-turn
transformer, RIS-480. This had a single turn 2-inch wide
copper strip primary, which was powered at 300kHz with 200V.
A 38-turn litz-wire secondary, with Q = 1000, pushed 7.5kV
into a coax cable and electrode load, with the help of a
15kV glass resonating vacuum capacitor, see some photos:

https://www.dropbox.com/sh/y8bch2i1nfbpusb/AABtrPpHhTRwtY9ocyFY9fHNa?dl=1



--
Thanks,
- Win

 

[whit3rd]

On Monday, October 14, 2019 at 5:50:28 PM UTC-4, John Larkin wrote:

On Mon, 14 Oct 2019 18:35:55 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

But you also have to be smart enough to know how to build an HV
transformer with 1500 turns on the secondary that operates unpotted.
You cannot simply 'scatter wind' it.

The problem under discussion is powering a bit of gear that's sitting
way off ground. So one secondary turn has to make a few volts out but
be *insulated* for kilovolts.

You only have to insulate against ADJACENT windings, though; with a 30 kV
goal, thirty layers (with tape) or adjacent buildups (with disk or air separators)
will work fine with the worst insulation (500V) one can get off-the-shelf
on the WIRE, the rest of the insulation in spacers and careful structural
design. And occasionally some spaghetti insulation... and a LOT
of attention to any conductive magnetic elements and fasteners.

The easiest way to make a mass-produced transformer doesn't look like a HV
transformer, though.