A question about coil winding
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From: ehsjr on 14 Jan 2010 12:17 John Fields wrote: > 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 Nice. A perfect center. Hike you said, and it made sense, most enjoyable. Ed
From: nospam on 14 Jan 2010 13:37 Josepi wrote: > You should show more confidence than to refer to yourself like that. This > seems to apply generally to your post browsing. > > Hi Sarah, how's things in Alaska?
From: John Fields on 14 Jan 2010 17:51 On Thu, 14 Jan 2010 12:17:54 -0500, ehsjr <ehsjr(a)nospamverizon.net> wrote: >John Fields wrote: >> 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 > >Nice. > >A perfect center. >Hike you said, and it made sense, >most enjoyable. > >Ed --- :-) JF
From: Jasen Betts on 14 Jan 2010 18:13 On 2010-01-14, 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? If I were to use a 10 strand > and only go around the coil form 200 times, would > it have the same effect? it'd behave basically the same as a single thicker strand > 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. no, it would be different, it'd peak sooner, but not neccessarily higher muliple joins could get you 2000 turns and similar performance to 2000 straight turns but inter-turn capacitance would be much worse. I would get a drill to turn the former and use some sort of counter to count turns, possibly the mechanical counter from an old VCR. --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: Michael B on 15 Jan 2010 23:59
On Jan 14, 7:31 am, John Fields <jfie...(a)austininstruments.com> wrote: > On Wed, 13 Jan 2010 17:42:23 -0800 (PST), Michael B > > <baugh...(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 Thanks. Lets me know I can't take a shortcut on another project. |