On Friday, October 6, 2023 at 1:18:20 AM UTC+11, John Larkin wrote:> On Thu, 5 Oct 2023 08:25:19 +0200, Klaus Vestergaard Kragelund <klau...@hotmail.com> wrote: > >On 29-09-2023 18:16, Lasse Langwadt Christensen wrote: > >> fredag den 29. september 2023 kl. 15.41.10 UTC+2 skrev Klaus Kragelund: > >>> On Thursday, 28 September 2023 at 23:09:44 UTC+2, Lasse Langwadt Christensen wrote: > >>>> torsdag den 28. september 2023 kl. 22.58.46 UTC+2 skrev Klaus Kragelund: > >>>>> On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote: > >>>>>> On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >>>>>>> On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>: > >>>>>>>> On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote: > >>>>>>>>> On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin <j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>: > >>>>>>>>>> On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >>>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>: > >>>>>>>>>>>> On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >>>>>>>>>>>>> On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin <j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>: > >>>>>>>>>>>>>> On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote:<snip>> >Maybe the isolation can be achieved by potting. That's a reasonable cheap way to boost the isolation voltage.\ > > Potting is an expensive mess.Ham-fisted people can mess it up.> A C-W multiplier can be spread out to maintain surface creepage limits. As an extreme defense against dust, it can have a cover or be conformally coated. > > My current plans are to have a single-inductor flyback and a C-W multiplier. That will use all multi-sourced parts (except for the control chip) and be all pick-and-place assembled, cheap parts of reels.It will cost a lot more than it needs to but the customer gets stuck with the price.> Designing for production is different from personal projects.Not if you allow your personal prejudices to govern what you design. -- Bill Sloman, Sydney
500 volt power supply
Started by ●September 24, 2023
Reply by ●October 6, 20232023-10-06
Reply by ●October 6, 20232023-10-06
On Friday, October 6, 2023 at 1:22:50 AM UTC+11, John Larkin wrote:> On Wed, 4 Oct 2023 08:24:08 -0700 (PDT), John Smiht > <utube...@xoxy.net> wrote: > > >On Tuesday, October 3, 2023 at 10:30:48?PM UTC-5, Anthony William Sloman wrote: > >> On Wednesday, October 4, 2023 at 3:00:46?AM UTC+11, John Larkin wrote: > >> > On Tue, 3 Oct 2023 16:41:27 +0200, Klaus Vestergaard Kragelund<klau...@hotmail.com> wrote: > >> > >On 03-10-2023 14:37, John Larkin wrote: > >> > >> On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau...@hotmail.com> wrote: > >> > >>> On 29-09-2023 04:09, John Larkin wrote: > >> > >>>> On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus.k...@gmail.com> wrote: > >> > >>>>> On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote: > >> > >>>>>> On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >> > >>>>>>> On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>: > >> > >>>>>>>> On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote: > >> > >>>>>>>>> On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin <j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>: > >> > >>>>>>>>>> On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >> > >>>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>: > >> > >>>>>>>>>>>> On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >> > >>>>>>>>>>>>> On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin <j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>: > >> > >>>>>>>>>>>>>> On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote: > >> <snip> > >> > >>> I will generate a single pulse, about 5us long, shaped like a half wave sinusoid, at 100kHz repetition frequency. That's why I was looking at flyback, since I can control the voltage delivered simply by adjusting the primary peak current. Power seems to be less than 5W, at 4.5kV peak, duty of let's say 25%. probably below 10mA > >> > >> > >> > >> One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine. > >> > >> > >> > >> This boosts 48 volts to 1400v at MHz pulse rates. > >> > >> > >> > >> http://www.highlandtechnology.com/DSS/T850DS.shtml > >> > >> > >> > >> by switching an inductor around. The energy is recovered and returned to the 48v supply after each pulse, which keeps the power dissipation under control. > >> > >> > >> > >> https://www.dropbox.com/scl/fi/lkjg19hvcus9xz8aeecxy/T850_Rev_C.JPG?rlkey=0pitv0zdmb0x1tz0fkw0gj3ob&raw=1 > >> > >> > >> > >> The really tricky stuff is on the bottom of the board, dumping heat into the water-cooled baseplate. > >> > >> > >> > >> At 5 us, you could make a 4KV DC supply and switch that into your load with a high-voltage mosfet. Brute force. > >> > >> > >> > >Yes, that could also be an idea. Will have some losses though, since it's switching into a capacitive load. > >> > > >> > Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too. > >> It isn't, if the load hasn't got any resistance. Discharging the capacitor into a separate supply isn't clever. > >> > So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That's how I got 4 MHz out of a tiny Pockels Cell driver. > >> What on earth is "F"? > > > >To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary. > > > Sloman isn't an engineer, he's a failed chemist.John Larkin doesn't like coping with reality. Getting a Ph.D, in chemistry made me a successful chemist, not a failed one and getting a couple of patents as an electronic engineer is fairly convincing evidence that I did succeed as an engineer.> I don't know what symbol failed chemists use for frequency.John Larkin clearly doesn't know what symbol electronic engineers use for frequency. In my experience they use "f" not "F" and in that context they'd mostly have used "2.pi..f". A lower case omega would also work. Omega (uppercase Ω, lowercase ω) is the 24th and last letter of the Greek alphabet. -- Bill Sloman, Sydney
Reply by ●October 6, 20232023-10-06
On Friday, October 6, 2023 at 3:25:28 AM UTC+11, John Larkin wrote:> On Thu, 5 Oct 2023 08:15:00 -0700 (PDT), John Smiht > <utube...@xoxy.net> wrote: > >On Thursday, October 5, 2023 at 9:22:50?AM UTC-5, John Larkin wrote: > >> On Wed, 4 Oct 2023 08:24:08 -0700 (PDT), John Smiht > >> <utube...@xoxy.net> wrote: > >> >> > Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too. > >> >> It isn't, if the load hasn't got any resistance. Discharging the capacitor into a separate supply isn't clever. > >> >> > So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That's how I got 4 MHz out of a tiny Pockels Cell driver. > >> >> What on earth is "F"? > >> > > >> >To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary. > >> > > >> Sloman isn't an engineer, he's a failed chemist. I don't know what > >> symbol failed chemists use for frequency. > > I'd respect his language skills more if he can ever learn the > difference between > > its > > and > > it's.Sadly, it's (a contraction of it is) a distinction that is vulnerable to typos. Flyguy, James Arthur and John Larkin do tend to be rude when other people make them. It's (not possessive) not an attractive habit. -- Bill Sloman, Sydney
Reply by ●October 6, 20232023-10-06
On Friday, October 6, 2023 at 4:56:58 AM UTC+11, Klaus Vestergaard Kragelund wrote:> On 05-10-2023 08:56, Anthony William Sloman wrote: > > On Thursday, October 5, 2023 at 5:20:53 PM UTC+11, Klaus Vestergaard Kragelund wrote: > >> On 03-10-2023 16:59, Anthony William Sloman wrote: > >>> On Wednesday, October 4, 2023 at 1:41:37 AM UTC+11, Klaus Vestergaard Kragelund wrote: > >>>> On 03-10-2023 14:37, John Larkin wrote: > >>>>> On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau...@hotmail.com> wrote: > >>>>>> On 29-09-2023 04:09, John Larkin wrote: > >>>>>>> On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus.k...@gmail.com> wrote: > >>>>>>>> On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote: > >>>>>>>>> On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus > >>>>>>>>>> Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>: > >>>>>>>>>>> On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote: > >>>>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin > >>>>>>>>>>>> <j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>: > >>>>>>>>>>>>> On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >>>>>>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>: > >>>>>>>>>>>>>>> On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote: > >>>>>>>>>>>>>>>> On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin > >>>>>>>>>>>>>>>> <j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>: > >>>>>>>>>>>>>>>>> On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote: > >>> > >>> <snip> > >>> > >>>>> One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine. > >>> > >>> A transformer would work better - perhaps several of them in series. > >>> > >>> Dump a bunch of current into the primaries in parallel - perhaps time shifted to allow the high voltage pulse to propagate through the series connected secondaries - and rely on the parallel capacitances of the secondaries to shape the pulse into a half-sine. > >>> > >> That's what I was considering doing, but still the individual > >> transformer needs to be able to handle the 4.5kV isolation from winding > >> to winding. > > > > Multisection formers make that easy enough. A single layer of 25 micron kapton tape is good for 4kV, and several layers for rather more, so you can do it on a single section former. > > > Yes, possible. Then a little dirt creeps in, poluted path, ionization, and sparks. Joerg would write "tssss, kaboom" etc ;-)It's called "tracking" and conformal coatings provide an answer. Cambridge Instruments made electron microscopes, typically 30kV machines. I didn't have much to do with the electron source, but had more to do with the photomultiplier (Everhart–Thornley) detector which we mostly ran below 1kV. I ran one a bit higher I wouldn't presume to predict what Jeorg would say. His most impressive feats were in medical ultrasound (where I've also worked) which doesn't use high voltages). On the subject of avoiding high voltages, could you split the drive to your electro optic modulator, so that one side went to down -2,25kV while the other side went up to +2.2.5kV? An incidental advantage is that you balance the the stray currents driven into the ground and get quite a lot less electromagnetic interference. A carefully made balanced transfomer drive with a grounded centre tap can do that rather well. -- Bill Sloman, Sydney
Reply by ●October 6, 20232023-10-06
On Friday, October 6, 2023 at 11:10:49 AM UTC+11, John Smiht wrote:> On Thursday, October 5, 2023 at 11:25:28 AM UTC-5, John Larkin wrote: > > On Thu, 5 Oct 2023 08:15:00 -0700 (PDT), John Smiht > > <utube...@xoxy.net> wrote: > > >On Thursday, October 5, 2023 at 9:22:50?AM UTC-5, John Larkin wrote: > > >> On Wed, 4 Oct 2023 08:24:08 -0700 (PDT), John Smiht > > >> <utube...@xoxy.net> wrote: > > >> >> > Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too. > > >> >> It isn't, if the load hasn't got any resistance. Discharging the capacitor into a separate supply isn't clever. > > >> >> > So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That's how I got 4 MHz out of a tiny Pockels Cell driver. > > >> >> What on earth is "F"? > > >> > > > >> >To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary. > > >> > > > >> Sloman isn't an engineer, he's a failed chemist. I don't know what symbol failed chemists use for frequency. > > > > > >+1John Larkin has his preferred delusions. Getting a Ph.D. in Physical Chemistry isn't what most people would described as a failure in chemistry. Since he doesn't know the symbol most elecronic engineers use for frequency, his ignorance about what ex-chemists might do isn't exactly surprising. He could seem enough examples my habits here, but he long ago worked that I don't post the flattery he craves, so he doesn't bother to look at them.> > I'd respect his language skills more if he can ever learn the difference between > > > > its > > > > and > > > > it's. > > Another +1Don't encourage him. It's not even his slur, but one he poached from James Arthur, who should have had enough sense not to confuse the occasional typo with actual ignorance. Not that James Arthur had much sense - he confessed to being a paid shill for the Koch brothers here (back when there were still two of them) and has gone quiet ever since. -- Bill Sloman, Sydney
Reply by ●October 6, 20232023-10-06
On Friday, October 6, 2023 at 8:04:14 AM UTC-5, Anthony William Sloman wrote:> On Friday, October 6, 2023 at 11:10:49 AM UTC+11, John Smiht wrote: > > On Thursday, October 5, 2023 at 11:25:28 AM UTC-5, John Larkin wrote: > > > On Thu, 5 Oct 2023 08:15:00 -0700 (PDT), John Smiht > > > <utube...@xoxy.net> wrote: > > > >On Thursday, October 5, 2023 at 9:22:50?AM UTC-5, John Larkin wrote: > > > >> On Wed, 4 Oct 2023 08:24:08 -0700 (PDT), John Smiht > > > >> <utube...@xoxy.net> wrote: > > > >> >> > Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too. > > > >> >> It isn't, if the load hasn't got any resistance. Discharging the capacitor into a separate supply isn't clever. > > > >> >> > So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That's how I got 4 MHz out of a tiny Pockels Cell driver. > > > >> >> What on earth is "F"? > > > >> > > > > >> >To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary. > > > >> > > > > >> Sloman isn't an engineer, he's a failed chemist. I don't know what symbol failed chemists use for frequency. > > > > > > > >+1 > John Larkin has his preferred delusions. Getting a Ph.D. in Physical Chemistry isn't what most people would described as a failure in chemistry. Since he doesn't know the symbol most elecronic engineers use for frequency, his ignorance about what ex-chemists might do isn't exactly surprising. He could seem enough examples my habits here, but he long ago worked that I don't post the flattery he craves, so he doesn't bother to look at them. > > > I'd respect his language skills more if he can ever learn the difference between > > > > > > its > > > > > > and > > > > > > it's. > > > > Another +1 > Don't encourage him. It's not even his slur, but one he poached from James Arthur, who should have had enough sense not to confuse the occasional typo with actual ignorance. > Not that James Arthur had much sense - he confessed to being a paid shill for the Koch brothers here (back when there were still two of them) and has gone quiet ever since. > > -- > Bill Sloman, SydneyFork you. I will encourage whomever I wish to encourage.
Reply by ●October 6, 20232023-10-06
On Fri, 6 Oct 2023 09:17:01 -0700 (PDT), John Smiht <utube.jocjo@xoxy.net> wrote:>On Friday, October 6, 2023 at 8:04:14?AM UTC-5, Anthony William Sloman wrote: >> On Friday, October 6, 2023 at 11:10:49?AM UTC+11, John Smiht wrote: >> > On Thursday, October 5, 2023 at 11:25:28?AM UTC-5, John Larkin wrote: >> > > On Thu, 5 Oct 2023 08:15:00 -0700 (PDT), John Smiht >> > > <utube...@xoxy.net> wrote: >> > > >On Thursday, October 5, 2023 at 9:22:50?AM UTC-5, John Larkin wrote: >> > > >> On Wed, 4 Oct 2023 08:24:08 -0700 (PDT), John Smiht >> > > >> <utube...@xoxy.net> wrote: >> > > >> >> > Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too. >> > > >> >> It isn't, if the load hasn't got any resistance. Discharging the capacitor into a separate supply isn't clever. >> > > >> >> > So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That's how I got 4 MHz out of a tiny Pockels Cell driver. >> > > >> >> What on earth is "F"? >> > > >> > >> > > >> >To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary. >> > > >> > >> > > >> Sloman isn't an engineer, he's a failed chemist. I don't know what symbol failed chemists use for frequency. >> > > > >> > > >+1 >> John Larkin has his preferred delusions. Getting a Ph.D. in Physical Chemistry isn't what most people would described as a failure in chemistry. Since he doesn't know the symbol most elecronic engineers use for frequency, his ignorance about what ex-chemists might do isn't exactly surprising. He could seem enough examples my habits here, but he long ago worked that I don't post the flattery he craves, so he doesn't bother to look at them. >> > > I'd respect his language skills more if he can ever learn the difference between >> > > >> > > its >> > > >> > > and >> > > >> > > it's. >> > >> > Another +1 >> Don't encourage him. It's not even his slur, but one he poached from James Arthur, who should have had enough sense not to confuse the occasional typo with actual ignorance. >> Not that James Arthur had much sense - he confessed to being a paid shill for the Koch brothers here (back when there were still two of them) and has gone quiet ever since. >> >> -- >> Bill Sloman, Sydney > >Fork you. I will encourage whomever I wish to encourage.Ignore Sloman. He's just here to insult people. He hasn't designed anything in decades.
Reply by ●October 6, 20232023-10-06
On 06-10-2023 06:35, Anthony William Sloman wrote:> On Friday, October 6, 2023 at 4:56:58 AM UTC+11, Klaus Vestergaard Kragelund wrote: >> On 05-10-2023 08:56, Anthony William Sloman wrote: >>> On Thursday, October 5, 2023 at 5:20:53 PM UTC+11, Klaus Vestergaard Kragelund wrote: >>>> On 03-10-2023 16:59, Anthony William Sloman wrote: >>>>> On Wednesday, October 4, 2023 at 1:41:37 AM UTC+11, Klaus Vestergaard Kragelund wrote: >>>>>> On 03-10-2023 14:37, John Larkin wrote: >>>>>>> On Tue, 3 Oct 2023 09:46:44 +0200, Klaus Vestergaard Kragelund <klau...@hotmail.com> wrote: >>>>>>>> On 29-09-2023 04:09, John Larkin wrote: >>>>>>>>> On Thu, 28 Sep 2023 13:58:40 -0700 (PDT), Klaus Kragelund <klaus.k...@gmail.com> wrote: >>>>>>>>>> On Thursday, 28 September 2023 at 17:26:46 UTC+2, John Larkin wrote: >>>>>>>>>>> On Thu, 28 Sep 2023 14:59:48 GMT, Jan Panteltje <al...@comet.invalid> wrote: >>>>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 13:34:29 -0700 (PDT)) it happened Klaus >>>>>>>>>>>> Kragelund <klaus.k...@gmail.com> wrote in <903144ac-6642-4a3f...@googlegroups.com>: >>>>>>>>>>>>> On Wednesday, 27 September 2023 at 17:38:35 UTC+2, Jan Panteltje wrote: >>>>>>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 08:10:02 -0700) it happened John Larkin >>>>>>>>>>>>>> <j...@997arbor.com> wrote in <d3h8hitm54oie4gcl...@4ax.com>: >>>>>>>>>>>>>>> On Wed, 27 Sep 2023 11:44:57 GMT, Jan Panteltje <al...@comet.invalid> wrote: >>>>>>>>>>>>>>>> On a sunny day (Wed, 27 Sep 2023 00:51:10 -0700) it happened John Larkin <j...@997arbor.com> wrote in <4bn7hit0n3rmcg855...@4ax.com>: >>>>>>>>>>>>>>>>> On Wed, 27 Sep 2023 05:14:49 GMT, Jan Panteltje <al...@comet.invalid> wrote: >>>>>>>>>>>>>>>>>> On a sunny day (Tue, 26 Sep 2023 19:35:18 -0700) it happened John Larkin >>>>>>>>>>>>>>>>>> <j...@997arbor.com> wrote in <mf47hi15db7eq7mp2...@4ax.com>: >>>>>>>>>>>>>>>>>>> On Sun, 24 Sep 2023 09:18:31 -0700, John Larkin <j...@997arbor.com> wrote: >>>>> >>>>> <snip> >>>>> >>>>>>> One can stuff a bunch of current into an inductor and then dump it into a mostly-capacitive load. That can make a high-voltage half-sine. >>>>> >>>>> A transformer would work better - perhaps several of them in series. >>>>> >>>>> Dump a bunch of current into the primaries in parallel - perhaps time shifted to allow the high voltage pulse to propagate through the series connected secondaries - and rely on the parallel capacitances of the secondaries to shape the pulse into a half-sine. >>>>> >>>> That's what I was considering doing, but still the individual >>>> transformer needs to be able to handle the 4.5kV isolation from winding >>>> to winding. >>> >>> Multisection formers make that easy enough. A single layer of 25 micron kapton tape is good for 4kV, and several layers for rather more, so you can do it on a single section former. >>> >> Yes, possible. Then a little dirt creeps in, poluted path, ionization, and sparks. Joerg would write "tssss, kaboom" etc ;-) > > It's called "tracking" and conformal coatings provide an answer. Cambridge Instruments made electron microscopes, typically 30kV machines. I didn't have much to do with the electron source, but had more to do with the photomultiplier (Everhart–Thornley) detector which we mostly ran below 1kV. I ran one a bit higher > > I wouldn't presume to predict what Jeorg would say. His most impressive feats were in medical ultrasound (where I've also worked) which doesn't use high voltages). > > On the subject of avoiding high voltages, could you split the drive to your electro optic modulator, so that one side went to down -2,25kV while the other side went up to +2.2.5kV? > > An incidental advantage is that you balance the the stray currents driven into the ground and get quite a lot less electromagnetic interference. A carefully made balanced transfomer drive with a grounded centre tap can do that rather well.That is a really good idea. I have done something similar when reducing common mode voltages for a half-bridge converter, but didn't think to use it in this application. Thanks for that :-)>
Reply by ●October 6, 20232023-10-06
On 10/6/2023 12:15 AM, Anthony William Sloman wrote:> On Friday, October 6, 2023 at 3:25:28 AM UTC+11, John Larkin wrote: >> On Thu, 5 Oct 2023 08:15:00 -0700 (PDT), John Smiht >> <utube...@xoxy.net> wrote: >>> On Thursday, October 5, 2023 at 9:22:50?AM UTC-5, John Larkin wrote: >>>> On Wed, 4 Oct 2023 08:24:08 -0700 (PDT), John Smiht >>>> <utube...@xoxy.net> wrote: >>>>>>> Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too. >>>>>> It isn't, if the load hasn't got any resistance. Discharging the capacitor into a separate supply isn't clever. >>>>>>> So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That's how I got 4 MHz out of a tiny Pockels Cell driver. >>>>>> What on earth is "F"? >>>>> >>>>> To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary. >>>>> >>>> Sloman isn't an engineer, he's a failed chemist. I don't know what >>>> symbol failed chemists use for frequency. >> >> I'd respect his language skills more if he can ever learn the >> difference between >> >> its >> >> and >> >> it's. > > Sadly, it's (a contraction of it is) a distinction that is vulnerable to typos. Flyguy, James Arthur and John Larkin do tend to be rude when other people make them. It's (not possessive) not an attractive habit. >Bill, you have written 252 ad hominem (what you term "rude") posts on this newsgroup since 7/15/2023. On several occasions I mentioned the (what I called negative) nature of what you posted in a reply to it. The "rude" posts to which I refer sometimes had worthwhile points in them in addition to the rude remarks, and sometimes not. But it (the rudeness in the posts) is so frequent as to be off putting. I told you my thinking - that you have something to offer - so please don't waste time on the negatives. Sadly it didn't work. I got to the point where I thought I was your only fan after wading through post after post where you denigrate the one to whom you are replying. I mention all of this because you told me it would be a kindness you would appreciate if someone pointed out your errors to you. You will undoubtedly think that you are without error in this, or that the rudeness was justified. Whatever. It's my loss to miss whatever good content you might post in place of ad hominem nonsense which adds nothing of value. Ex fan. Ed
Reply by ●October 7, 20232023-10-07
On Saturday, October 7, 2023 at 9:15:58 AM UTC+11, ehsjr wrote:> On 10/6/2023 12:15 AM, Anthony William Sloman wrote: > > On Friday, October 6, 2023 at 3:25:28 AM UTC+11, John Larkin wrote: > >> On Thu, 5 Oct 2023 08:15:00 -0700 (PDT), John Smiht > >> <utube...@xoxy.net> wrote: > >>> On Thursday, October 5, 2023 at 9:22:50?AM UTC-5, John Larkin wrote: > >>>> On Wed, 4 Oct 2023 08:24:08 -0700 (PDT), John Smiht > >>>> <utube...@xoxy.net> wrote: > >>>>>>> Switching a DC supply into a capacitive load is inherently lossy, and people usually discharge the cap and waste that energy, too. > >>>>>> It isn't, if the load hasn't got any resistance. Discharging the capacitor into a separate supply isn't clever. > >>>>>>> So power dissipation is C*F*V^2. The inductor trick has, ideally, zero power dissipation... it just sloshes energy around. That's how I got 4 MHz out of a tiny Pockels Cell driver. > >>>>>> What on earth is "F"? > >>>>> > >>>>> To an engineer it means, in this context, frequency. So to you it might mean something else in your fancy vocabulary. > >>>>> > >>>> Sloman isn't an engineer, he's a failed chemist. I don't know what symbol failed chemists use for frequency.<snip>> > Sadly, it's (a contraction of it is) a distinction that is vulnerable to typos. Flyguy, James Arthur and John Larkin do tend to be rude when other people make them. It's (not possessive) not an attractive habit. > > > Bill, you have written 252 ad hominem (what you term "rude") posts on this newsgroup since 7/15/2023. On several occasions I mentioned the (what I called negative) nature of what you posted in a reply to it.So why aren't you calli g out John Larkin?> The "rude" posts to which I refer sometimes had worthwhile points in them in addition to the rude remarks, and sometimes not. > But it (the rudeness in the posts) is so frequent as to be off putting.Tough. Get used to it. People like John Larkin, who have a very high opinion of their own competence, don't pay any attention to posts pointing out their errors unless the point is make very clear,.> > I told you my thinking - that you have something to offer - so please don't waste time on the negatives. Sadly it didn't work. > I got to the point where I thought I was your only fan after wading through post after post where you denigrate the one to whom you are replying.I'll take all the fans I can get, but I've been rude to people who are mostly pretty reliable. We are all human and make mistakes from time to time.> I mention all of this because you told me it would be a kindness you would appreciate if someone pointed out your errors to you. > You will undoubtedly think that you are without error in this, or that the rudeness was justified.I never think that I am without error. I do think that a lot of the rudeness is necessary and justified, but it is likely that I could get much the same effectt - usually none - if I were more polite.> > Whatever. It's my loss to miss whatever good content you might post in place of ad hominem nonsense which adds nothing of value.It get the attention of the target - briefly.,> Ex fan.I'll live. -- Bill Sloman, Sydney
