On 08/05/2016 01:57 PM, John Larkin wrote:> On Fri, 05 Aug 2016 09:24:31 -0700, John Larkin > <jjlarkin@highlandtechnology.com> wrote: > >> On 5 Aug 2016 05:53:42 -0700, Winfield Hill <hill@rowland.harvard.edu> >> wrote: >> >>> bill.sloman@ieee.org wrote... >>>> >>>> Too many people make a habit of avoiding custom magnetics. >>>> The Rowland Institute ought to have a simple coil winder - >>>> there are cheap ones available from China if it doesn't - >>>> and you don't need much of a range of RM cores, formers, >>>> mylar tape and enamelled wire to do useful stuff. >>> >>> We have a winder, but need an fixture for small bobbins. >>> I have the full range of materials, including my favorite >>> Kapton tape, in various widths. It's the painful magnet- >>> wire enamel removal and soldering to tiny bobbin pins >>> that slows me down. That'd be an even worse issue with >>> extra windings. But I heard a rumor about a special >>> magnet wire with disappearing enamel at soldering temps. >> >> Beldsol, thermal strip. I got a high-temp Metcal clone tip from >> Amazon, >> >> https://www.amazon.com/Thermaltronics-S75CH015-Chisel-interchangeable-SSC-738A/dp/B00NS4E0YW >> >> that solders this stuff great. >> >> https://dl.dropboxusercontent.com/u/53724080/Parts/Inductors/TEM1_Xfmr_Proto.JPG >> >> >> I hate custom magnetics. Expensive, boring hassle. The technical >> challenge of designing transformers is to NOT design transformers. > > Search ebay for Beldsol wire > > I got my #28 cheap from that antique dealer in Virginia. > >Beldsol costs the earth. I get very similar stuff from Temco for a fraction of the price (also eBay). Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
inductor for HV flyback supply
Started by ●August 5, 2016
Reply by ●August 5, 20162016-08-05
Reply by ●August 5, 20162016-08-05
On Fri, 5 Aug 2016 14:13:32 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 08/05/2016 01:57 PM, John Larkin wrote: >> On Fri, 05 Aug 2016 09:24:31 -0700, John Larkin >> <jjlarkin@highlandtechnology.com> wrote: >> >>> On 5 Aug 2016 05:53:42 -0700, Winfield Hill <hill@rowland.harvard.edu> >>> wrote: >>> >>>> bill.sloman@ieee.org wrote... >>>>> >>>>> Too many people make a habit of avoiding custom magnetics. >>>>> The Rowland Institute ought to have a simple coil winder - >>>>> there are cheap ones available from China if it doesn't - >>>>> and you don't need much of a range of RM cores, formers, >>>>> mylar tape and enamelled wire to do useful stuff. >>>> >>>> We have a winder, but need an fixture for small bobbins. >>>> I have the full range of materials, including my favorite >>>> Kapton tape, in various widths. It's the painful magnet- >>>> wire enamel removal and soldering to tiny bobbin pins >>>> that slows me down. That'd be an even worse issue with >>>> extra windings. But I heard a rumor about a special >>>> magnet wire with disappearing enamel at soldering temps. >>> >>> Beldsol, thermal strip. I got a high-temp Metcal clone tip from >>> Amazon, >>> >>> https://www.amazon.com/Thermaltronics-S75CH015-Chisel-interchangeable-SSC-738A/dp/B00NS4E0YW >>> >>> that solders this stuff great. >>> >>> https://dl.dropboxusercontent.com/u/53724080/Parts/Inductors/TEM1_Xfmr_Proto.JPG >>> >>> >>> I hate custom magnetics. Expensive, boring hassle. The technical >>> challenge of designing transformers is to NOT design transformers. >> >> Search ebay for Beldsol wire >> >> I got my #28 cheap from that antique dealer in Virginia. >> >> > >Beldsol costs the earth. I get very similar stuff from Temco for a >fraction of the price (also eBay). > >Cheers > >Phil HobbsThe ebay #28 was $17 for a quarter-pound spool, which will last me a long time. Magnet wire is expensive. I got one quote for litz equivalent of #28 that was $150 per pound. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●August 5, 20162016-08-05
On 08/05/2016 03:43 PM, John Larkin wrote:> On Fri, 5 Aug 2016 14:13:32 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 08/05/2016 01:57 PM, John Larkin wrote: >>> On Fri, 05 Aug 2016 09:24:31 -0700, John Larkin >>> <jjlarkin@highlandtechnology.com> wrote: >>> >>>> On 5 Aug 2016 05:53:42 -0700, Winfield Hill >>>> <hill@rowland.harvard.edu> wrote: >>>> >>>>> bill.sloman@ieee.org wrote... >>>>>> >>>>>> Too many people make a habit of avoiding custom magnetics. >>>>>> The Rowland Institute ought to have a simple coil winder - >>>>>> there are cheap ones available from China if it doesn't - >>>>>> and you don't need much of a range of RM cores, formers, >>>>>> mylar tape and enamelled wire to do useful stuff. >>>>> >>>>> We have a winder, but need an fixture for small bobbins. I >>>>> have the full range of materials, including my favorite >>>>> Kapton tape, in various widths. It's the painful magnet- >>>>> wire enamel removal and soldering to tiny bobbin pins that >>>>> slows me down. That'd be an even worse issue with extra >>>>> windings. But I heard a rumor about a special magnet wire >>>>> with disappearing enamel at soldering temps. >>>> >>>> Beldsol, thermal strip. I got a high-temp Metcal clone tip from >>>> Amazon, >>>> >>>> https://www.amazon.com/Thermaltronics-S75CH015-Chisel-interchangeable-SSC-738A/dp/B00NS4E0YW >>>> >>>> >>>> >>>>that solders this stuff great.>>>> >>>> https://dl.dropboxusercontent.com/u/53724080/Parts/Inductors/TEM1_Xfmr_Proto.JPG >>>> >>>> >>>> >>>> >>>>I hate custom magnetics. Expensive, boring hassle. The technical>>>> challenge of designing transformers is to NOT design >>>> transformers. >>> >>> Search ebay for Beldsol wire >>> >>> I got my #28 cheap from that antique dealer in Virginia. >>> >>> >> >> Beldsol costs the earth. I get very similar stuff from Temco for >> a fraction of the price (also eBay).> The ebay #28 was $17 for a quarter-pound spool, which will last me a > long time.Yeah, I usually buy a career's worth of stuff like that too. I'll never need to buy Kester 44 again, since I got 10 spools NOS. ;)> Magnet wire is expensive. I got one quote for litz equivalent of #28 > that was $150 per pound.Well, there's a lot of processing that goes into that. CPU dice are pretty expensive per pound. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●August 5, 20162016-08-05
On 8/5/2016 2:43 PM, John Larkin wrote:> On Fri, 5 Aug 2016 14:13:32 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 08/05/2016 01:57 PM, John Larkin wrote: >>> On Fri, 05 Aug 2016 09:24:31 -0700, John Larkin >>> <jjlarkin@highlandtechnology.com> wrote: >>> >>>> On 5 Aug 2016 05:53:42 -0700, Winfield Hill <hill@rowland.harvard.edu> >>>> wrote: >>>> >>>>> bill.sloman@ieee.org wrote... >>>>>> >>>>>> Too many people make a habit of avoiding custom magnetics. >>>>>> The Rowland Institute ought to have a simple coil winder - >>>>>> there are cheap ones available from China if it doesn't - >>>>>> and you don't need much of a range of RM cores, formers, >>>>>> mylar tape and enamelled wire to do useful stuff. >>>>> >>>>> We have a winder, but need an fixture for small bobbins. >>>>> I have the full range of materials, including my favorite >>>>> Kapton tape, in various widths. It's the painful magnet- >>>>> wire enamel removal and soldering to tiny bobbin pins >>>>> that slows me down. That'd be an even worse issue with >>>>> extra windings. But I heard a rumor about a special >>>>> magnet wire with disappearing enamel at soldering temps. >>>> >>>> Beldsol, thermal strip. I got a high-temp Metcal clone tip from >>>> Amazon, >>>> >>>> https://www.amazon.com/Thermaltronics-S75CH015-Chisel-interchangeable-SSC-738A/dp/B00NS4E0YW >>>> >>>> that solders this stuff great. >>>> >>>> https://dl.dropboxusercontent.com/u/53724080/Parts/Inductors/TEM1_Xfmr_Proto.JPG >>>> >>>> >>>> I hate custom magnetics. Expensive, boring hassle. The technical >>>> challenge of designing transformers is to NOT design transformers. >>> >>> Search ebay for Beldsol wire >>> >>> I got my #28 cheap from that antique dealer in Virginia. >>> >>> >> >> Beldsol costs the earth. I get very similar stuff from Temco for a >> fraction of the price (also eBay). >> >> Cheers >> >> Phil Hobbs > > The ebay #28 was $17 for a quarter-pound spool, which will last me a > long time. > > Magnet wire is expensive. I got one quote for litz equivalent of #28 > that was $150 per pound.+1 on the Beldsol. I use it rather than wire wrap wire for prototype mods. Easier than stripping the 30ga wire.
Reply by ●August 5, 20162016-08-05
On 08/05/2016 04:09 PM, John S wrote:> On 8/5/2016 2:43 PM, John Larkin wrote: >> On Fri, 5 Aug 2016 14:13:32 -0400, Phil Hobbs >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >>> On 08/05/2016 01:57 PM, John Larkin wrote: >>>> On Fri, 05 Aug 2016 09:24:31 -0700, John Larkin >>>> <jjlarkin@highlandtechnology.com> wrote: >>>> >>>>> On 5 Aug 2016 05:53:42 -0700, Winfield Hill <hill@rowland.harvard.edu> >>>>> wrote: >>>>> >>>>>> bill.sloman@ieee.org wrote... >>>>>>> >>>>>>> Too many people make a habit of avoiding custom magnetics. >>>>>>> The Rowland Institute ought to have a simple coil winder - >>>>>>> there are cheap ones available from China if it doesn't - >>>>>>> and you don't need much of a range of RM cores, formers, >>>>>>> mylar tape and enamelled wire to do useful stuff. >>>>>> >>>>>> We have a winder, but need an fixture for small bobbins. >>>>>> I have the full range of materials, including my favorite >>>>>> Kapton tape, in various widths. It's the painful magnet- >>>>>> wire enamel removal and soldering to tiny bobbin pins >>>>>> that slows me down. That'd be an even worse issue with >>>>>> extra windings. But I heard a rumor about a special >>>>>> magnet wire with disappearing enamel at soldering temps. >>>>> >>>>> Beldsol, thermal strip. I got a high-temp Metcal clone tip from >>>>> Amazon, >>>>> >>>>> https://www.amazon.com/Thermaltronics-S75CH015-Chisel-interchangeable-SSC-738A/dp/B00NS4E0YW >>>>> >>>>> >>>>> that solders this stuff great. >>>>> >>>>> https://dl.dropboxusercontent.com/u/53724080/Parts/Inductors/TEM1_Xfmr_Proto.JPG >>>>> >>>>> >>>>> >>>>> I hate custom magnetics. Expensive, boring hassle. The technical >>>>> challenge of designing transformers is to NOT design transformers. >>>> >>>> Search ebay for Beldsol wire >>>> >>>> I got my #28 cheap from that antique dealer in Virginia. >>>> >>>> >>> >>> Beldsol costs the earth. I get very similar stuff from Temco for a >>> fraction of the price (also eBay). >>> >>> Cheers >>> >>> Phil Hobbs >> >> The ebay #28 was $17 for a quarter-pound spool, which will last me a >> long time. >> >> Magnet wire is expensive. I got one quote for litz equivalent of #28 >> that was $150 per pound. > > +1 on the Beldsol. I use it rather than wire wrap wire for prototype > mods. Easier than stripping the 30ga wire.Me too. Cheers Phil Hobbs-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●August 5, 20162016-08-05
On Friday, August 5, 2016 at 12:46:12 PM UTC-4, Winfield Hill wrote:> dagmargoodboat@yahoo.com wrote... > > > > John beat me to suggesting coupled inductors ... I got > > distracted simulating one. > > > > A boost inductor charged for 8us @ 12V, will discharge > > into 500V in 8us * 12V/(500V-12V) = 200ns. That's pretty > > fast! And quite a whack for your rectifier and filter > > components. > > Well, even my poor inductors can do that well,I didn't mean it was hard to do, rather, that it's hard on the rectifier, and lossy downstream.> the issue > is high-frequency core loss.Continuous mode helps that loss by reducing the a.c. flux in the core, which is another disadvantage to that super-fast discharge time--there aren't many PWM ICs fast enough when the required maximum discharge time is ~100nS to keep the inductor current in continuous mode! But that asymmetric duty cycle is the problem with high-ratio dc-to-dc flybacks in the first place, as we all know. That's why it's sometimes helpful to slow things down, e.g. coupled inductor, larger-valued inductor, or both. Continuous, if one can manage it, cuts peak currents in half too, reducing i^2*r loss.> I'd rather use commercial > inductors than a custom.Amen! Winding magnetics in production is a pain.> Looking over available stuff, > I've been discouraged by a lack of the right info. But > newly-designed parts tend to work better, maybe because > the newer smps ICs are running faster, to over 1MHz. > > Anyway, yes, coupled inductors are awesome. I've used > a few in recent designs and have been accumulating a > collection of candidate parts for experimenting. > > > Driving the tap of two coupled inductors in series lets > > you double the discharge time, halve the discharge > > current, and halve the switch's voltage rating. > > > > It's kind of a nice option for low-power high-ratio > > dc-dc converters, short of resorting to a forward > > converter with a custom transformer. > > They're jelly-bean, e.g.: > > http://www.mouser.com/ds/2/597/msd1278-220442.pdf > >http://www.mouser.com/Passive-Components/Inductors/Coupled-Inductors/_/N-afrbk?Rl=afrbkZer9dZ1z0wqgnZ1z0wqavSGTafrbkZgjdhkrZ1yzcffhZ1yc9bmgSGT > > Right. My test universal-supply PCB layout predated > my interest in coupled inductors, but I'll shoehorn > one in there to see how it works.Cheers, James Arthur
Reply by ●August 5, 20162016-08-05
On 8/5/2016 3:12 PM, Phil Hobbs wrote:> On 08/05/2016 04:09 PM, John S wrote: >> On 8/5/2016 2:43 PM, John Larkin wrote: >>> On Fri, 5 Aug 2016 14:13:32 -0400, Phil Hobbs >>> <pcdhSpamMeSenseless@electrooptical.net> wrote: >>> >>>> On 08/05/2016 01:57 PM, John Larkin wrote: >>>>> On Fri, 05 Aug 2016 09:24:31 -0700, John Larkin >>>>> <jjlarkin@highlandtechnology.com> wrote: >>>>> >>>>>> On 5 Aug 2016 05:53:42 -0700, Winfield Hill <hill@rowland.harvard.edu> >>>>>> wrote: >>>>>> >>>>>>> bill.sloman@ieee.org wrote... >>>>>>>> >>>>>>>> Too many people make a habit of avoiding custom magnetics. >>>>>>>> The Rowland Institute ought to have a simple coil winder - >>>>>>>> there are cheap ones available from China if it doesn't - >>>>>>>> and you don't need much of a range of RM cores, formers, >>>>>>>> mylar tape and enamelled wire to do useful stuff. >>>>>>> >>>>>>> We have a winder, but need an fixture for small bobbins. >>>>>>> I have the full range of materials, including my favorite >>>>>>> Kapton tape, in various widths. It's the painful magnet- >>>>>>> wire enamel removal and soldering to tiny bobbin pins >>>>>>> that slows me down. That'd be an even worse issue with >>>>>>> extra windings. But I heard a rumor about a special >>>>>>> magnet wire with disappearing enamel at soldering temps. >>>>>> >>>>>> Beldsol, thermal strip. I got a high-temp Metcal clone tip from >>>>>> Amazon, >>>>>> >>>>>> https://www.amazon.com/Thermaltronics-S75CH015-Chisel-interchangeable-SSC-738A/dp/B00NS4E0YW >>>>>> >>>>>> >>>>>> that solders this stuff great. >>>>>> >>>>>> https://dl.dropboxusercontent.com/u/53724080/Parts/Inductors/TEM1_Xfmr_Proto.JPG >>>>>> >>>>>> >>>>>> >>>>>> I hate custom magnetics. Expensive, boring hassle. The technical >>>>>> challenge of designing transformers is to NOT design transformers. >>>>> >>>>> Search ebay for Beldsol wire >>>>> >>>>> I got my #28 cheap from that antique dealer in Virginia. >>>>> >>>>> >>>> >>>> Beldsol costs the earth. I get very similar stuff from Temco for a >>>> fraction of the price (also eBay). >>>> >>>> Cheers >>>> >>>> Phil Hobbs >>> >>> The ebay #28 was $17 for a quarter-pound spool, which will last me a >>> long time. >>> >>> Magnet wire is expensive. I got one quote for litz equivalent of #28 >>> that was $150 per pound. >> >> +1 on the Beldsol. I use it rather than wire wrap wire for prototype >> mods. Easier than stripping the 30ga wire. > > Me too. > > Cheers > > Phil Hobbs-- > Dr Philip C D HobbsI've posted a picture many times of a tool I got about 34 yrs ago when I worked at an electric motor repair shop. The hand tool is very convenient for scraping the varnish from almost any size wire. > http://s395.photobucket.com/user/Qmavam/media/WireStripperinhand.jpg.html> http://s395.photobucket.com/user/Qmavam/media/WireStripper.jpg.htmlJust 3 or 4 pinch and pull maneuvers and the copper is clean. As pictured you can see I broke one blade about 15 years ago, but it has not affected its use. If anyone is interested in purchase, I should have a link on my other computer. I think it is a very handy tool, but no one has ever shown the any interest, even though I know people are using an exacto knife and trying to scrape insulation of off tiny wire. Mikek
Reply by ●August 5, 20162016-08-05
On 8/5/2016 4:37 PM, amdx wrote:> > I've posted a picture many times of a tool I got about 34 yrs ago > when I worked at an electric motor repair shop. The hand tool is very > convenient for scraping the varnish from almost any size wire. >> http://s395.photobucket.com/user/Qmavam/media/WireStripperinhand.jpg.html >> http://s395.photobucket.com/user/Qmavam/media/WireStripper.jpg.html > Just 3 or 4 pinch and pull maneuvers and the copper is clean. > As pictured you can see I broke one blade about 15 years ago, but it has > not affected its use. > If anyone is interested in purchase, I should have a link on my other > computer. I think it is a very handy tool, but no one has ever shown the > any interest, even though I know people are using an exacto knife and > trying to scrape insulation of off tiny wire. > Mikek >I found the link. See center of page 10, labeled 'Wire Skinner and Straightener'.> http://martindaleco.com/pdfs/Electricians_Hand_Tools/Hand%20Tools.pdfMikek
Reply by ●August 5, 20162016-08-05
[snip]>> > >> I think Win is charging a capacitor. Forward converters are very > >> inefficient when heavily loaded, namely when the capacitor voltage is > >> low. Most of the voltage drop is in the mosfets or the transformer > >> copper. > >> > >> An ideal flyback can be 100% efficient over the entire charging curve. > >> > > > >Forward converters are not inefficient. It's just a transformer fed buck converter, so in the beginning of Wins charge cycle, he of course needs to start with 0 duty cycle > > The forward converter needs an additional load-side inductor, and > input current limiting, to be efficient. And two mosfets. A > current-mode flyback switcher is simpler. Forwards are usually used > for higher-power apps.Correct about the load-side inductor, but no it does not need input current limiting I have used forwards for less than 1W applications, if you need high efficiency then the forward can be scaled like any converter to almost any size although a >500W flyback borders to a crazy design The flyback is a saturation limited converter, in that it used 1st quadrant fully of the BH curve, so the optimization of losses are normally not done for a flyback. For the forward you can design the flux swing like you want, so you can arrange the flux losses to equal conduction losses, which is the optimal design Cheers Klaus
Reply by ●August 5, 20162016-08-05
On 8/5/2016 4:50 PM, amdx wrote:> On 8/5/2016 4:37 PM, amdx wrote: > >> >> I've posted a picture many times of a tool I got about 34 yrs ago >> when I worked at an electric motor repair shop. The hand tool is very >> convenient for scraping the varnish from almost any size wire. >>> http://s395.photobucket.com/user/Qmavam/media/WireStripperinhand.jpg.html >>> >>> http://s395.photobucket.com/user/Qmavam/media/WireStripper.jpg.html >> Just 3 or 4 pinch and pull maneuvers and the copper is clean. >> As pictured you can see I broke one blade about 15 years ago, but it has >> not affected its use. >> If anyone is interested in purchase, I should have a link on my other >> computer. I think it is a very handy tool, but no one has ever shown the >> any interest, even though I know people are using an exacto knife and >> trying to scrape insulation of off tiny wire. >> Mikek >> > I found the link. See center of page 10, labeled 'Wire Skinner and > Straightener'. > >> http://martindaleco.com/pdfs/Electricians_Hand_Tools/Hand%20Tools.pdf > > MikekOops, Page 9. Mikek
