A question about coil winding
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From: John Fields on 14 Jan 2010 07:31 On Wed, 13 Jan 2010 17:42:23 -0800 (PST), Michael B <baughfam(a)bellsouth.net> wrote: >No. >The field strength is related to the number of coils. >So if I start out and go around the coil form 2,000 >times with one wire, could I get the same effect by >using a multistrand, with each strand insulated >from the adjacent one? --- Well, finally, something that makes sense! :-) Yes. --- >If I were to use a 10 strand >and only go around the coil form 200 times, would >it have the same effect? --- No. --- >Litz wire would not have much current capacity, --- Litz wire is simply insulated wire stranded in a peculiar way in order to reduce skin effect, and can have any current capacity required for the application at hand. http://en.wikipedia.org/wiki/Litz_wire >but would it have the same instantaneous magnetic field >from a capacitive discharge? For the initial spike: Version 4 SHEET 1 880 680 WIRE 64 0 0 0 WIRE 224 0 128 0 WIRE 224 32 224 0 WIRE 0 128 0 0 WIRE 224 160 224 112 WIRE 0 288 0 208 WIRE 224 288 224 240 WIRE 224 288 0 288 WIRE 0 368 0 288 FLAG 0 368 0 SYMBOL ind 208 144 R0 SYMATTR InstName L1 SYMATTR Value 1e-3 SYMBOL res 208 16 R0 SYMATTR InstName R1 SYMATTR Value 1000 SYMBOL cap 128 -16 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 1e-9 SYMBOL voltage 0 112 R0 WINDOW 3 24 104 Invisible 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value PULSE(0 10 0 1e-9) TEXT -34 392 Left 0 !.tran 1e-3 --- >It's not a question of multiple solder joints along the way, >it would be a beginning, and an end, with wires soldered >together at those points only. --- If you use stranded wire to make a coil with all of the strands soldered together at the ends but insulated from each other at every other point, then the resistance of each strand will be the end-to-end resistance of the wire multiplied by the number of strands in the wire, and the current in each strand will be: 1 Is = ---- It where Is is the current in any strand and It is the total current in the wire. Since the strands are in parallel, the total resistance of the wire will be: 1 Rt = ------ Rs n where Rt is the total resistance of the wire, Rs is the resistance of a single strand, and n is the number of strands in the wire. Graphically, (View in Courier) for a raw 1000' length of seven strand enameled #10 AWG wire we have: |<----------1000 feet------------>| |<------------7 ohms------------->| --------------------------------- |<------------7 ohms------------->| --------------------------------- |<------------7 ohms------------->| --------------------------------- |<------------7 ohms------------->| --------------------------------- |<------------7 ohms------------->| --------------------------------- |<------------7 ohms------------->| --------------------------------- |<------------7 ohms------------->| --------------------------------- while with the ends soldered together,: |<-----------1000 feet---------->| |<-------------1 ohm------------>| | | +--------------------------------+ | | +--------------------------------+ | | +--------------------------------+ | | +--------------------------------+ | | +--------------------------------+ | | +--------------------------------+ | | +--------------------------------+ Now, since I've answered your question courteously, would you extend me the courtesy of bottom posting a reply, please? JF
From: John Fields on 14 Jan 2010 07:44 On Thu, 14 Jan 2010 11:59:02 +0000, baron <baron.nospam(a)linuxmaniac.nospam.net> wrote: >John Fields Inscribed thus: > >> >>>On Jan 12, 10:06�am, John Fields <jfie...(a)austininstruments.com> >>>wrote: >> >> On Tue, 12 Jan 2010 14:35:34 -0800 (PST), Michael B >> <baughfam(a)bellsouth.net> wrote: >> >>>>it's not like we'd be any worse off without you. >> >>>You're right. You've done a good job of making things bad, >>>I doubt anyone could make it much worse. >> >> --- >> Made things bad??? >> >> All I've done is point out to you that, on USENET, bottom posting is >> preferable to top posting and that your incessant use of the evil top >> posting method is frowned upon by most of USENET and even advised >> against by Google Groups, that bastion for the clueless and thorn in >> the side of USENET. >> >> You, on the other hand, are part of the problem and have decided to >> fight tooth and nail against changing your posting style to one that >> is used by easily 90% of the rest of us because you think it's more >> important to be inflammatory and keep playing your little troll games. >> >> A good example is the IKYABWAI nonsense with which you started this >> post. >> >> I really have no need to waste any more of my precious time replying >> to your inane prattle, so unless you can come up with something >> intersting, goodbye. >> >> JF > >Just block "Google Groups" period. Problem gone... --- You're right, but some of the posts from Google Groups are OK, though, and if I did a global block I'd miss them, so plonking the goons or just ignoring them might be better. JF
From: Josepi on 14 Jan 2010 10:21 You should show more confidence than to refer to yourself like that. This seems to apply generally to your post browsing. <nospam(a)nevis.com> wrote in message news:4b4e7148$1(a)news.x-privat.org... I'm using a newsreader that does all that, you are the problem, not anyone's newsreader. By top posting and misappropriating quotes nobody has any idea who or what you are referring to. Josepi wrote: > I guess that proves it then by your fine example. Thanx > > Time to get rid of that cheap POS "newsreader" that use try to browse > Usenets posts with, apparently. > > Get one that can thread and read the associated headers with the text and > try to keep any relevent text with your response. This will make it more > apparent what you are referring to next time. > >
From: Josepi on 14 Jan 2010 10:28 NO. Not the same effect. If you soldered the ends of the multistrands you would have 200 turns only. You would have 10 parallel coils sharing current, unevenly, due to connection differences and differing reluctance between strands. For 2000 turns, you put the form in a hand drill, measure the gearing step up ratio and count hand crank turns mentally. 2000 / 10 = 200 turns only. "Michael B" <baughfam(a)bellsouth.net> wrote in message news:5ca00b3b-0c77-47ad-8145-bd6d5bd0a2e6(a)k17g2000yqh.googlegroups.com... No. The field strength is related to the number of coils. So if I start out and go around the coil form 2,000 times with one wire, could I get the same effect by using a multistrand, with each strand insulated from the adjacent one? If I were to use a 10 strand and only go around the coil form 200 times, would it have the same effect? Litz wire would not have much current capacity, but would it have the same instantaneous magnetic field from a capacitive discharge? It's not a question of multiple solder joints along the way, it would be a beginning, and an end, with wires soldered together at those points only. On Jan 13, 12:14 pm, "Josepi" <J...(a)invaliid.con> wrote: > Well done! > > Do you have a lot of this multi-strand wire to use for a cheap price? > > I think it would make the winding too complicated. Instead of many turns > you > will have days of soldering connections to get all the strands in series. > That's a huge lump you may not have room for.
From: John Fields on 14 Jan 2010 12:05
On Thu, 14 Jan 2010 10:28:55 -0500, "Josepi" <JRM(a)invaliid.con> wrote: >NO. Not the same effect. If you soldered the ends of the multistrands you >would have 200 turns only. You would have 10 parallel coils sharing current, >unevenly, due to connection differences and differing reluctance between >strands. > >For 2000 turns, you put the form in a hand drill, measure the gearing step >up ratio and count hand crank turns mentally. 2000 / 10 = 200 turns only. --- The snow hid it well. he slipped and fell, the knife killed, but there was no loss. JF |