Designing HV transformers.

[Rich Grise]

On Wed, 25 May 2005 08:40:40 +0200, Fred Bartoli wrote:

Make a zip of all files and just use www.yousendit.com

Hey! That looks handier than a rat! I wonder how they make their
living?

Cheers!
Rich

 

[Joel Kolstad]

"Rich Grise" <richgrise@example.net> wrote in message
newsan.2005.05.25.14.57.54.651652@example.net...

Hey! That looks handier than a rat! I wonder how they make their
living?

Advertising when you go to pick up the file? Google's Gmail seems to be able
to support itself with this model, surprisingly enough!

 

[Winfield Hill]

Mebart wrote...

Want 20 or 40 mb worth of web info on them?? Ive got a big collection
of files in my personal library. Say the word and I'll ship them via
email.

I'd love to get a copy of that amazing pile you've gathered.
My mailbox has no overall limits that I'm aware of, although I
usually don't go much over 10MB per email message, to be safe.

I can put the pile on our ftp server, for others, if you like.
My email is, ahem, hill-atthingie-rowland-dot-org


--
Thanks,
- Win

 

[Joel Kolstad]

Win & others,

Mebart has begun sending me his data, and I'll stick it on a web site after I
get it all and have bundled it up.

---Joel

 

[Mebart]

OK, I'll send to Win also, or is it easier to wait for the website???

On Wed, 25 May 2005 11:13:37 -0700, "Joel Kolstad"
<JKolstad71HatesSpam@yahoo.com> wrote:

Win & others,

Mebart has begun sending me his data, and I'll stick it on a web site after I
get it all and have bundled it up.

---Joel

 

[Winfield Hill]

Mebart wrote...

OK, I'll send to Win also, or is it easier to wait for the website???

If it's not that hard to send it to my email address, I'd
certainly appreciate it. My curiosity is at a fever pitch.


--
Thanks,
- Win

 

[Pooh Bear]

Frithiof Andreas Jensen wrote:

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4293E37C.FA04AA25@hotmail.com...

Use triple insulated wire and your problems go away.

... or are replaced by unwanted resonances and capacitive losses. Distance
is Good!

Care to elaborate ?

Graham

 

[Mebart]

OK, I will forward them to you, all the messages are under 9 mb, some
are much smaller.

Over the years, you've been a pretty mellow type-can't imagine a fever
pitch in Win's house.

Standby for massive email.......

M

On 25 May 2005 15:26:43 -0700, Winfield Hill
<hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

Mebart wrote...

OK, I'll send to Win also, or is it easier to wait for the website???

If it's not that hard to send it to my email address, I'd
certainly appreciate it. My curiosity is at a fever pitch.

 

[Mebart]

OK, I moved some of the atachments and files around, so forwarding the
message sent previously to Joel won't work as the files can't be found
by the email program.

It will take me awhile as I will have to hunt down everything and try
to keep from sending too many duplicate files.

I'll get the files out of the old archive and start with them. The
newer archive is scattered and will take a little longer to sort out.


Regards,

M



On 25 May 2005 15:26:43 -0700, Winfield Hill
<hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

Mebart wrote...

OK, I'll send to Win also, or is it easier to wait for the website???

If it's not that hard to send it to my email address, I'd
certainly appreciate it. My curiosity is at a fever pitch.

 

[Rich Grise]

On Wed, 25 May 2005 09:58:43 -0700, Winfield Hill wrote:

Mebart wrote...

Want 20 or 40 mb worth of web info on them?? Ive got a big collection
of files in my personal library. Say the word and I'll ship them via
email.

I'd love to get a copy of that amazing pile you've gathered.
My mailbox has no overall limits that I'm aware of, although I
usually don't go much over 10MB per email message, to be safe.

I can put the pile on our ftp server, for others, if you like.
My email is, ahem, hill-atthingie-rowland-dot-org

If they're plain text, they zip up amazingly well. I wouldn't be
surprised to see 40 MB of plain text (or even HTML) compress to under
5 MB of zip.

Cheers!
Rich

 

[Mebart]

Thanks Rich,

They are mostly pdf's with a few gifs and a few word files........they
won't compress well.

Regards,

M

On Thu, 26 May 2005 01:01:49 GMT, Rich Grise <richgrise@example.net>
wrote:

On Wed, 25 May 2005 09:58:43 -0700, Winfield Hill wrote:

Mebart wrote...

Want 20 or 40 mb worth of web info on them?? Ive got a big collection
of files in my personal library. Say the word and I'll ship them via
email.

I'd love to get a copy of that amazing pile you've gathered.
My mailbox has no overall limits that I'm aware of, although I
usually don't go much over 10MB per email message, to be safe.

I can put the pile on our ftp server, for others, if you like.
My email is, ahem, hill-atthingie-rowland-dot-org

If they're plain text, they zip up amazingly well. I wouldn't be
surprised to see 40 MB of plain text (or even HTML) compress to under
5 MB of zip.

Cheers!
Rich

 

[Mebart]

Win, I have 5 email message ready to send to you with the data. I did
find a few of the files I was missing when I snet the info to Joel.
Namely, a very nice close up picture of a PZT showing both sides and
the original 1999 article in EDN that inspired me to look for sources
of these parts and to learn about them.

I sent you a short test message to your un-munged email address to
make sure I had decoded it ok, but didn't get a reply.

I used 000h0ill 0at0 0roland00 d0ot or0g, take out the 0's to
un-munge.

Hope you received the test email, if so, just drop me a line saying
you got it and I'll let those emails fly.

Regards,

M

On Wed, 25 May 2005 15:36:53 -0400, Mebart <> wrote:

OK, I'll send to Win also, or is it easier to wait for the website???

On Wed, 25 May 2005 11:13:37 -0700, "Joel Kolstad"
JKolstad71HatesSpam@yahoo.com> wrote:

Win & others,

Mebart has begun sending me his data, and I'll stick it on a web site after I
get it all and have bundled it up.

---Joel

 

[Winfield Hill]

Mebart wrote...

Win, I have 5 email message ready to send to you with the data. I did
find a few of the files I was missing when I snet the info to Joel.
Namely, a very nice close up picture of a PZT showing both sides and
the original 1999 article in EDN that inspired me to look for sources
of these parts and to learn about them.

I sent you a short test message to your un-munged email address to
make sure I had decoded it ok, but didn't get a reply.

I used 000h0ill 0at0 0roland00 d0ot or0g, take out the 0's to
un-munge.

Hope you received the test email, if so, just drop me a line saying
you got it and I'll let those emails fly.

I really look to getting those email packages. Just change the
spelling by adding a w, to rowland, and we should be all set.


--
Thanks,
- Win

 

[Frithiof Andreas Jensen]

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4295033E.FE3DE0E1@hotmail.com...

Care to elaborate ?

Sure,

When I designed HV transformers, I found that above about 3 kV, the majority
of the problems with losses, corona, ringing and so on are caused by
inter-winding capacitance and capacitive coupling to the core.

Winding the secondary with all layers in the same direction and rectifiers
inbetween layers make almost all
the trouble go away. The voltage builds up as you get away from the core.
The interwinding capacitances can then help filtering and the voltage swings
at the end of the windings will be in the same direction, i.e. zero between
windings.


Like:

-------D|---------------> HV
| =
*~~~~~~~~~ --|
| =
-------D|------ --|
| =
*~~~~~~~~~ --|
| =
-------D|------ --|
| =
*~~~~~~~~~ --|
|
GND


To get this to work, you need long, single layer, windings; i.e. Thin Wire
and good distance to the core at the ends of the windings. So the triple
insulation does not help - it displaces Air with material with higher
capacitance, putting more stress on the remaining air gaps. You get corona.

A special former split into multiple "disc" sections will also work,
provided they are "stacked" like shown. Those are easier to wind, but the
formers and cores that match them are hard to get in quantities below 200000
;-)

Resonant converters help a lot because they have lower rise times so less
capacitive current will flow and you transformer will have loads of leakage
anyway that it would be a shame to fight against.

Finally, you probably want to keep switching frequency low, 25-30 kHz
maybe - the creepage distance is what dimensions the core so you are not
going to beat the conference circut with 1 MW/cm3 anyway.


PS:

If it really has to be cheap and you do not mind cheating, a modern Ignition
Coil for a Car can typically deliver about 40 W at 12 Kv when driven from a
single end resonant converter. Flyback works too at less efficiency.

Boss didn't like that particular solution because Customer would spot the
obvious COTS part and begin to worry about what he should really pay for the
unit - which would not be good because the price tag was about 70 times the
cost ab factory!!

 

[Frithiof Andreas Jensen]

"Rich Grise" <richgrise@example.net> wrote in message
newsan.2005.05.25.14.57.54.651652@example.net...

On Wed, 25 May 2005 08:40:40 +0200, Fred Bartoli wrote:

Make a zip of all files and just use www.yousendit.com

Hey! That looks handier than a rat! I wonder how they make their
living?

"Cash Flow from Financing" ... i.e. pension money from propellerheads buying
the stock for their retirement!

 

[Mebart]

I really look to getting those email packages. Just change the
spelling by adding a w, to rowland, and we should be all set.

OK, that explains why you didn't reply to the test message, glad I
waited to confirm I had your address right.

wroland looks good to me.

standby.

M

 

[Winfield Hill]

Mebart wrote...

I really look to getting those email packages. Just change the
spelling by adding a w, to rowland, and we should be all set.

OK, that explains why you didn't reply to the test message, glad
I waited to confirm I had your address right.

wroland looks good to me.

standby.

Hah! OK, got it all, what a haul, thanks! Should I post this
mass of great stuff to our ftp server?


--
Thanks,
- Win

 

[Joel Kolstad]

By the time you read this, you should be able to download "PiezoXfrmr.zip"
from http://oregonstate.edu/~kolstadj/ . It should be all the files Mebart
has... if I've missed any, please let me know and I'll happily add them!

---Joel

 

[Terry Given]

Mebart wrote:

On Tue, 24 May 2005 16:03:17 -0700, "Joel Kolstad"
JKolstad71HatesSpam@yahoo.com> wrote:


Yeah, I found the Panasonic units at DigiKey and was amazed to see that
Panasonic then doesn't actually know anything about them on their web site.
Sheesh!


This is fairly typical of the entire industry. No one has specs
listed, and the one single vendor who does has some serious errors in
his listing! Complete characterization necessary for Spice simulations
is non-existant. I am NOT kidding about this!



Sure! Although I'm not certain I actually have any e-mail accounts that'll
accept a file that big. I don't suppose there's an FTP or HTTP site you
could place a ZIP archive of them all?


I'm not sure-I know yahoo gives 20 mb of free web space if you start a
mailing list. I have 10 mb of personal web space, but that won't even
start to cover all the materail I have.

How often do you check your mail??? I can forward a mb or two each day
till you holler STOP. Is your email address in the header ok?

Regards,

M

Hi M,

could you please include me in that distribution as well. substitute my
name for my_name (IOW firstname_lastname@IEEE.org). I have been
interested in these things for some time also (but again, have yet to
find one I can really buy/use)

Cheers
Terry

 

[Terry Given]

Joerg wrote:

Hello Joseph,

The main thing is an absense of any sharp edges,


Why is this important? I do notice that the TV ones are rounded inside
next to the winding but have corners outside.


Mostly to avoid corona or arcing. Far enough away from the winding it
isn't so important. Another concern is if the wire is to be wound
directly onto the bare or taped core. Any burrs can damage the insulation.

Regards, Joerg

I would also point out that "sharp" (IOW not well radiused) edges can
cause long-term problems with winding insulation, which is stressed
around a tight corner. The inside edge insulation gets squished up, and
the outer edge gets thinned out. Add heat + time, and creep may well result.

I had a hilarious argument with a so-called mechanical engineer about
this once. He reckoned that a 2.8mm dia. O-ring, bent 90 degrees around
a 1mm radius, maintains its shape. I reckoned he was an idiot. I was
right, water poured in at the edges. Of course he did have a 2.8mm
channel for the O-ring at the corner (cf 2.5mm elsewhere). The O-ring
thinned out by about 0.3mm. Even showing him the o-ring under a
microscope wasnt enough to convince him. It convinced me never to use
him again.

His fix was to use a 3mm O-ring, which made the unit impossible to
assemble. His fix for that was to use vaseline, which then destroyed
(completely! looked like a sledge hammer had been used) $300,000 worth
of polycarbonate-based plastic enclosures, which *he* had designed and
made. His choice of material, too. It took about 3 months for the scale
of the problem to become apparent, in the field. At that stage, lawyers
were called (and I learned a lot about the interaction of plastics and
other goodies)


Cheers
Terry