Litz wire
in [Design]
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From: Tim Williams on 20 Feb 2010 01:06 See the beast of a transformer in this thing? http://myweb.msoe.edu/williamstm/Images/Induction1201.jpg That's one use of the rope I found (where the plastic covering is peeled away, you can even see the cool ropey ropeness of it -- pretty!). That's 20 turns, and each turn is maybe 8" long, or 160" = 13.3' total. If it's actually 231 strand as I speculated earlier, that's 3kft, more than half a mile of 28AWG. Now, if I build more of these, I don't need quite this many strands since it's only running at 20kHz. But the 1MHz thing I mentioned elsewhere needs wire at least this fine. http://www.bcae1.com/trnsfrmr.htm Neet, this calculator suggests I want 242 x 36AWG to get something resembling 12AWG. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms "life imitates life" <pasticcio(a)thebarattheendoftheuniverse.org> wrote in message news:ssoun5tma9nl5gsfae0v809045t0hahpjg(a)4ax.com... > On Fri, 19 Feb 2010 13:21:36 -0600, "Tim Williams" > <tmoranwms(a)charter.net> wrote: > >>Who sells this stuff (without paying for miles at a time)? >> >>I'm especially interested in stupid thick stuff, like, as large as 8AWG >>equivalent. Nebraska Surplus for instance doesn't stock wire like this. >> >>Tim > > Pick a gauge, buy the mag wire, and make your own. It is not that hard > at all. Properly braiding out a custom length of Litz wire is no harder > that winding your own custom pot core transformer bobbin. One just has to > set one's mind to it, and accomplish a simple task without assigning > undue difficulty to it without even trying. > > Can't be any harder than macrame. You can actually come up with better > stuff than you can even buy too. > > The stuff you refer to sounds like it would not be a cheap per foot > price, even if you were buying a whole spool. Probably better to fashion > a double long length, then cut it in half when you are ready to use it. > > What is the application , and the length of the run? Or is it needing > to be long enough to be a primary winding?
From: life imitates life on 20 Feb 2010 01:06 On Fri, 19 Feb 2010 17:57:41 -0800, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Fri, 19 Feb 2010 13:21:36 -0600, "Tim Williams" ><tmoranwms(a)charter.net> wrote: > >>Who sells this stuff (without paying for miles at a time)? >> >>I'm especially interested in stupid thick stuff, like, as large as 8AWG >>equivalent. Nebraska Surplus for instance doesn't stock wire like this. >> >>Tim > >I've seen power inductors wound from a bundle of smaller-gage enameled >wires just bunched together in parallel and gang soldered on the ends, >but not woven like proper Litz. That apparently cuts eddy currents a >bunch. MWS sells this style too, a bunch strands of smallish wire >loosely twisted together, with thermal-strip insulation. > >John The definition of Litz relies on the fact that the strands are electrically segregated from each other between their terminus points. It does NOT HAVE to be specially braided or woven. The thermal strip wrapped stuff DOES qualify as litz, depending on length and intended application, and I have bought the MWS product before. The proof? I made several of my own Litz configuration primaries for transformers and the proof is in the pudding of the observed performance characteristics, even at lower frequency switcher supply cycle rates. The fact is that it definitely works to segregate several strands of conductor on short runs of AC pathways or in inductors and chokes and transformer windings. Trial and error with gauges and strand count do more to optimize the result than ANY specialized, presumed to be required braiding or weaving. The segregation is the key to increasing surface area within a given cumulative "gauge".
From: life imitates life on 20 Feb 2010 03:29 On Sat, 20 Feb 2010 00:06:07 -0600, "Tim Williams" <tmoranwms(a)charter.net> wrote: >See the beast of a transformer in this thing? >http://myweb.msoe.edu/williamstm/Images/Induction1201.jpg >That's one use of the rope I found (where the plastic covering is peeled >away, you can even see the cool ropey ropeness of it -- pretty!). > >That's 20 turns, and each turn is maybe 8" long, or 160" = 13.3' total. If >it's actually 231 strand as I speculated earlier, that's 3kft, more than >half a mile of 28AWG. > >Now, if I build more of these, I don't need quite this many strands since >it's only running at 20kHz. But the 1MHz thing I mentioned elsewhere needs >wire at least this fine. > >http://www.bcae1.com/trnsfrmr.htm >Neet, this calculator suggests I want 242 x 36AWG to get something >resembling 12AWG. > >Tim STOP top posting. If it is non-segregated "rope" as you call it, it is no different than welding cable and is merely being used as a flexible, high current link to the winding or as the winding media itself, but there will be NO "Litz function" if the individual strands are not isolated from each other electrically along the length of the conductor. All the strands of Litz type wire co-conduct *apart* from each other, EXCEPT at the ends where they are ALL terminated at the same node. Other wise there is no litz configuration and there will be no litz effect or function taking place. The "rope" or cable as it is properly called, will have a single "skin effect realm" that surrounds the entire bundle and NONE of the inner wires will carry any current in high freq rf conduction. With segregated wires, each has their own skin and the total amount of conducting copper in an rf conduction setting is an order of magnitude greater. Of course strand gauge has an effect on that and the improvement will be less with larger strands, but they ALL MUST conduct separate from each other except at their common endpoint nodes, or there is no effect.
From: Tim Williams on 20 Feb 2010 03:47 I see you don't view links. The wire is clearly individually insulated, which is what everyone else in this thread understands by "litz", except yourself, as you have stated six times over. It's a good thing you're in everyone's killfile. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms "life imitates life" <pasticcio(a)thebarattheendoftheuniverse.org> wrote in message news:is6vn51ugmurkn1fkp7lmltlscghl3mfo0(a)4ax.com... > On Sat, 20 Feb 2010 00:06:07 -0600, "Tim Williams" > <tmoranwms(a)charter.net> wrote: > >>See the beast of a transformer in this thing? >>http://myweb.msoe.edu/williamstm/Images/Induction1201.jpg >>That's one use of the rope I found (where the plastic covering is peeled >>away, you can even see the cool ropey ropeness of it -- pretty!). >> >>That's 20 turns, and each turn is maybe 8" long, or 160" = 13.3' total. >>If >>it's actually 231 strand as I speculated earlier, that's 3kft, more than >>half a mile of 28AWG. >> >>Now, if I build more of these, I don't need quite this many strands since >>it's only running at 20kHz. But the 1MHz thing I mentioned elsewhere >>needs >>wire at least this fine. >> >>http://www.bcae1.com/trnsfrmr.htm >>Neet, this calculator suggests I want 242 x 36AWG to get something >>resembling 12AWG. >> >>Tim > > > STOP top posting. > > If it is non-segregated "rope" as you call it, it is no different than > welding cable and is merely being used as a flexible, high current link > to the winding or as the winding media itself, but there will be NO "Litz > function" if the individual strands are not isolated from each other > electrically along the length of the conductor. > > All the strands of Litz type wire co-conduct *apart* from each other, > EXCEPT at the ends where they are ALL terminated at the same node. > > Other wise there is no litz configuration and there will be no litz > effect or function taking place. The "rope" or cable as it is properly > called, will have a single "skin effect realm" that surrounds the entire > bundle and NONE of the inner wires will carry any current in high freq rf > conduction. With segregated wires, each has their own skin and the total > amount of conducting copper in an rf conduction setting is an order of > magnitude greater. Of course strand gauge has an effect on that and the > improvement will be less with larger strands, but they ALL MUST conduct > separate from each other except at their common endpoint nodes, or there > is no effect.
From: life imitates life on 20 Feb 2010 04:54
On Sat, 20 Feb 2010 00:06:07 -0600, "Tim Williams" <tmoranwms(a)charter.net> wrote: >That's 20 turns, and each turn is maybe 8" long, or 160" = 13.3' total. If >it's actually 231 strand as I speculated earlier, that's 3kft, more than >half a mile of 28AWG. 231 strands of #28 would be bigger in diameter than that wire appears to be. Even 231 strands of #38 or #43 would be pretty big. No way that those are #28 strands, or if they are, there are not 231 of them. Use some common sense. 231 strands of #28 single strength mag wire has a bundle diameter of nearly 3/8"! Your #12 ga arrival math is off too. D=Diameter of a bundle of wires d=diameter of a single strand in the bundle N=Total number of wires. D= 1.55 x d x (Sq rt of N) The #12 is about 0.083" in diameter without a wrap. The 242 strands of #36 you stated is 0.0056" in diameter, which is for single strength mag wire, and comes out to 0.135" So, the lesson is DO NOT forget the insulation. |