On Fri, 5 Aug 2016 15:09:55 -0500, John S <Sophi.2@invalid.org> 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.I've used #30 Beldsol on breadboards, but it was a tad hard to solder. My new hi-temp ersatz Metcal tip should fix that. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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 Friday, August 5, 2016 at 10:54:06 PM UTC+10, Winfield Hill wrote:> bill.sloman@ieee.org wrote...<snip>> 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.It's called self-fluxing wire. My usual source has it. https://www.scientificwire.com/acatalog/ec-wire.html and I'm fairly sure that most wire-manufacturers do it. The other cute trick is self-bonding enamel. Wind the coil, then put enough current through it to get it to the bonding temperature, and when it cools down you have a self-supporting coil. Great for saddle coils and other fancy stuff. Wind them circular, bend into the saddle shape, then bond. Winding your own coils isn't just for transformers and inductors. -- Bill Sloman, Sydney
Reply by ●August 5, 20162016-08-05
Den lørdag den 6. august 2016 kl. 01.08.36 UTC+2 skrev John Larkin:> On Fri, 5 Aug 2016 15:09:55 -0500, John S <Sophi.2@invalid.org> 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. > > I've used #30 Beldsol on breadboards, but it was a tad hard to solder. > My new hi-temp ersatz Metcal tip should fix that. >the trick is to start from exposed copper on a fresh cut end, it get a good thermal connection and the solder seems to wick under the isolation and burn it off -Lasse
Reply by ●August 6, 20162016-08-06
On Fri, 5 Aug 2016 18:17:51 -0700 (PDT), Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:>Den l�rdag den 6. august 2016 kl. 01.08.36 UTC+2 skrev John Larkin: >> On Fri, 5 Aug 2016 15:09:55 -0500, John S <Sophi.2@invalid.org> 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. >> >> I've used #30 Beldsol on breadboards, but it was a tad hard to solder. >> My new hi-temp ersatz Metcal tip should fix that. >> > >the trick is to start from exposed copper on a fresh cut end, it get a good thermal connection and the solder seems to wick under the isolation and burn it off > >-LasseScraping it a bit with an x-acto helps start the process better. But the real trick is to use a very hot iron. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●August 6, 20162016-08-06
In article <hv6aqbpeijv859bufaj6afk65vvireigt2@4ax.com>, John Larkin <jjlarkin@highlandtechnology.com> wrote:> On Fri, 5 Aug 2016 15:09:55 -0500, John S <Sophi.2@invalid.org> 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-SS > >>>>> C-738A/dp/B00NS4E0YW > >>>>> > >>>>> that solders this stuff great. > >>>>> > >>>>> > >>>>> https://dl.dropboxusercontent.com/u/53724080/Parts/Inductors/TEM1_Xfmr_P > >>>>> roto.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. > > I've used #30 Beldsol on breadboards, but it was a tad hard to solder. > My new hi-temp ersatz Metcal tip should fix that.The trick with Beldsol is to use a very hot iron with enough thermal mass to raise the connection above 750 F more or less instantly. Then its a puff of smoke and done, and nothing has time to melt. Joe Gwinn
Reply by ●August 6, 20162016-08-06
On 05/08/2016 17:24, John Larkin 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. > >I bought a selection of about a dozen Thermaltronics tips (for a Metcal 500) about three years ago when they were first released. About 75% of them have failed. By comparison I've about 30 original tips (many bought 2nd hand) all over 4 years old and I can't recall any failures. I don't know if Thermaltronics have improved in quality but I don't think I'll be bothering to find out any time soon. Incidentally, I prefer the JBC system to the Metcal, but their soldering stations are not very reliable in my experience. Out of warranty repair cost from the manufacturer seems to be about the same cost as the purchase of a new unit. A DIY chap realeased an open hardware design (Unisolder) which can work with JBC, Metcal and various other handpieces. I'm going to give it a try the next time I have a JBC station failure.
Reply by ●August 6, 20162016-08-06
On Sat, 06 Aug 2016 19:02:15 +0100, JM <dontreplytothis173@gmail.com> wrote:>On 05/08/2016 17:24, John Larkin 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. >> >> > >I bought a selection of about a dozen Thermaltronics tips (for a Metcal >500) about three years ago when they were first released. About 75% of >them have failed.I only use the Thermaltronics tips on thermal-strip wire, which is a very low duty cycle. They are too hot for normal soldering.> >By comparison I've about 30 original tips (many bought 2nd hand) all >over 4 years old and I can't recall any failures.Right, the Metcal tips are amazingly reliable and long-lasting, at least for engineering-bench use. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●August 6, 20162016-08-06
"John Larkin" <jjlarkin@highlandtechnology.com> wrote in message news:fc5cqb1nmgosknh2d1jfjcvgejldrtqk62@4ax.com...>>the trick is to start from exposed copper on a fresh cut end, it get a >>good thermal connection and the solder seems to wick under the isolation >>and burn it off > > Scraping it a bit with an x-acto helps start the process better. But > the real trick is to use a very hot iron."Self fluxing" is a bit of a misnomer. Rosin helps, probably acting as a solvent to get the enamel moving. A "very hot iron" may work against you, as the stuff (both enamel and rosin) turns to char and ashes before washing away. This is all very easily confirmed visually, so do whatever looks best. If it's charring, turn it down. If it's not getting hot, and flux isn't helping, turn it up. Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
Reply by ●August 6, 20162016-08-06
On Saturday, August 6, 2016 at 2:24:37 AM UTC+10, John Larkin 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.<snip>> I hate custom magnetics. Expensive, boring hassle. The technical > challenge of designing transformers is to NOT design transformers.Sadly, the habit of not designing transformers leaves you stuck with messy, expensive, sub-optimal solutions. The design process is complicated, with lots of choices, but no more boring than any other design process. I suspect that what you are saying is that you've never bothered to get your head around all the issues involved, and find yourself embarrassed when you have to discuss a transformer design in front of your subordinates. There are lots of variables in a transformer design - starting with core size and core material, gapped or ungapped, and proceeding through turns ratio and wire size, and choosing between plain wire and Litz, and on to winding configuration - bifilar or separate coils - plain windings or winding in banks (for lower parallel capacitance). This means that buying an off-the-transformer is unlikely to give you anything all that close to optimal. The process of getting small runs of custom transformers made by sub-contractors isn't all that demanding - no worse than printed circuit boards. It's nice if you can avoid it, but little more sensible than it would be to insist of building everything on off-the-shelf printed circuit boards. -- Bill Sloman, Sydney
Reply by ●August 7, 20162016-08-07
On Friday, August 5, 2016 at 9:05:33 PM UTC+10, Winfield Hill wrote:> bill.sloman@ieee.org wrote... > > > >On Friday, August 5, 2016 at 1:07:26 PM UTC+10, Winfield Hill wrote:<snip>> >http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillator1.htm<snip>> BTW, some of your web article links are broken.I think I've now found and - probably - fixed the problem. Some of the links were to my old Dutch web-site, long since dismantled. It will be some hours before my IP up-loads the corrected file, and I won't know if it has worked until then. -- Bill Sloman, sydney
