Brain dead here, that's set to median thickness,
But instead of point currents which take a lot of time to draw in, how about more curves and then use the "circuit" properties. That way you automatically get inductance per turns squared.
- Robert -
On Mon, 25 Aug 2003 10:04:51 -0700 Dave Squires <djsquires@plix.com> wrote: > > > > > Come on guys. This is easy. > The attached file shows you how to do this. > Remember this is static, not dynamic. But this > will work fine for getting the field. This would > be a no load condition. For a loaded case you > would have to calculate the rate of change, > figure the voltage induced and the current based > on the load. Depending whether the field is > rising or falling in the primary you can determine > the Lenz reaction polarity accordingly to oppose > or assist the primary drive. I will leave that > up to the user to handle all the other details. > > The main trick is to use point currents for the > coil windings. Just run the attached file. > David Meeker can fill you in on any other way > to do this. But this is one way. > > DRS > > robert Macy wrote: > > The torroidal transformer *is* axisymmetric, but > when drawn > > that way the currents go around the small circle and > the > > magnetic field is perpendicular to the page. I > don't think > > femm solves this situation. > > > > Instead and approximation is to draw the cross > sectional > > view in x-y form and set the total length to the > median > > circumference. > > > > The "crunching" of the field at the inside > curve won't show > > up, but it will get you started. > > > > > - Robert - > > > > On Mon, 25 Aug 2003 03:16:32 -0000 > > "Dr Mark Snoswell" > <mark@cgCharacter.com> wrote: > > > >> > >> > >> > >>How do I model the field of a torroidal > transformer? ... > >>it's axi > >>symetric but I can't quite see hwo to model it. > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >>Yahoo! Groups Sponsor > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >>Your use of Yahoo! Groups is subject to the > Yahoo! Terms > >>of Service. > >> > >> > >> > >> > > > > > > > > > > > > > > Your use of Yahoo! Groups is subject to > http://docs.yahoo.com/info/terms/ > > > > > > > > > ---------- > > [Format] = 3.3 > [Frequency] = 0 > [Precision] = 1e-008 > [Depth] = 1 > [LengthUnits] = inches > [ProblemType] = planar > [Coordinates] = cartesian > [Comment] = "Add > comments here." > [PointProps] = 2 > <BeginPoint> > <PointName> = > "Primary-plus" > <I_re> = 5 > <I_im> = 0 > <A_re> = 0 > <A_im> = 0 > <EndPoint> > <BeginPoint> > <PointName> = > "Primary-minus" > <I_re> = -5 > <I_im> = 0 > <A_re> = 0 > <A_im> = 0 > <EndPoint> > [BdryProps] = 0 > [BlockProps] = 2 > <BeginBlock> > <BlockName> = "Air" > <Mu_x> = 1 > <Mu_y> = 1 > <H_c> = 0 > <H_cAngle> = 0 > <J_re> = 0 > <J_im> = 0 > <Sigma> = 0 > <d_lam> = 0 > <Phi_h> = 0 > <Phi_hx> = 0 > <Phi_hy> = 0 > <LamType> = 0 > <LamFill> = 1 > <BHPoints> = 0 > <EndBlock> > <BeginBlock> > <BlockName> = "M-19 > Steel" > <Mu_x> = 4416 > <Mu_y> = 4416 > <H_c> = 0 > <H_cAngle> = 0 > <J_re> = 0 > <J_im> = 0 > <Sigma> = 0 > <d_lam> = 0 > <Phi_h> = 0 > <Phi_hx> = 0 > <Phi_hy> = 0 > <LamType> = 0 > <LamFill> = 1 > <BHPoints> = 13 > > 0 0 > > 0.29999999999999999 > 39.78875 > > 0.80000000000000004 > 79.577500000000001 > > 1.1200000000000001 159.155 > > 1.3200000000000001 318.31 > > 1.46 795.77499999999998 > > 1.54 1591.55 > > 1.6187499999999999 > 3376.6669999999999 > > 1.74 7957.75 > > 1.8700000000000001 15915.5 > > 1.99 31831 > > 2.0459640000000001 > 55102.040000000001 > > 2.0800000000000001 79577.5 > <EndBlock> > [CircuitProps] = 0 > [NumPoints] = 114 > -1 > 0 > 0 0 > -1.75 > 0 > 0 0 > 1 > 0 > 0 0 > 1.75 > 0 > 0 0 > -0.18192272946553939 > 0.85587915064207998 > 2 0 > -0.38983442028329873 > 1.8340267513758857 > 1 0 > -0.27038987007807896 > 0.83217445175825933 > 2 0 > -0.57940686445302636 > 1.7832309680534129 > 1 0 > -0.35589456269132513 > 0.79935227543727572 > 2 0 > -0.76263120576712529 > 1.7128977330798767 > 1 0 > -0.43749999999999994 > 0.75777222831138391 > 2 0 > -0.93749999999999989 > 1.6237976320958225 > 1 0 > -0.51431209575591397 > 0.70788987007807902 > 2 0 > -1.1020973480483871 > 1.5169068644530266 > 1 0 > -0.58548928056400096 > 0.65025172229271999 > 2 0 > -1.2546198869228591 > 1.3933965477701142 > 1 0 > -0.65025172229271988 > 0.58548928056400096 > 2 0 > -1.393396547770114 > 1.2546198869228591 > 1 0 > -0.70788987007807902 > 0.51431209575591397 > 2 0 > -1.5169068644530266 > 1.1020973480483871 > 1 0 > -0.7577722283113838 > 0.43750000000000011 > 2 0 > -1.6237976320958223 > 0.93750000000000022 > 1 0 > -0.79935227543727572 > 0.35589456269132519 > 2 0 > -1.7128977330798767 > 0.7626312057671254 > 1 0 > -0.83217445175825933 > 0.27038987007807902 > 2 0 > -1.7832309680534129 > 0.57940686445302647 > 1 0 > -0.85587915064207987 > 0.18192272946553953 > 2 0 > -1.8340267513758854 > 0.38983442028329895 > 1 0 > -0.8702066584472391 > 0.09146240535919678 > 2 0 > -1.8647285538155125 > 0.19599086862685022 > 1 0 > -0.875 > 5.3576527979729005e-017 > 2 0 > -1.875 > 1.1480684567084787e-016 > 1 0 > -0.87020665844723921 > 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0.70788987007807902 > 0.51431209575591397 > 0 0 > 1.5169068644530266 > 1.1020973480483871 > 0 0 > 0.7577722283113838 > 0.43750000000000011 > 0 0 > 1.6237976320958223 > 0.93750000000000022 > 0 0 > 0.79935227543727572 > 0.35589456269132519 > 0 0 > 1.7128977330798767 > 0.7626312057671254 > 0 0 > 0.83217445175825933 > 0.27038987007807902 > 0 0 > 1.7832309680534129 > 0.57940686445302647 > 0 0 > 0.85587915064207987 > 0.18192272946553953 > 0 0 > 1.8340267513758854 > 0.38983442028329895 > 0 0 > 0.8702066584472391 > 0.09146240535919678 > 0 0 > 1.8647285538155125 > 0.19599086862685022 > 0 0 > 0.875 > 5.3576527979729005e-017 > 0 0 > 1.875 > 1.1480684567084787e-016 > 0 0 > 0.87020665844723921 > -0.091462405359196669 > 0 0 > 1.8647285538155127 > -0.19599086862685 > 0 0 > 0.85587915064207998 > -0.18192272946553922 > 0 0 > 1.8340267513758857 > -0.38983442028329834 > 0 0 > 0.83217445175825944 > -0.27038987007807891 > 0 0 > 1.7832309680534131 > -0.57940686445302625 > 0 0 > 0.79935227543727583 > -0.35589456269132502 > 0 0 > 1.7128977330798769 > -0.76263120576712506 > 0 0 > 0.75777222831138391 > -0.43749999999999978 > 0 0 > 1.6237976320958225 > -0.93749999999999956 > 0 0 > 0.70788987007807902 > -0.51431209575591386 > 0 0 > 1.5169068644530266 > -1.1020973480483869 > 0 0 > 0.65025172229271999 > -0.58548928056400096 > 0 0 > 1.3933965477701142 > -1.2546198869228591 > 0 0 > 0.58548928056400107 > -0.65025172229271977 > 0 0 > 1.2546198869228593 > -1.3933965477701138 > 0 0 > 0.51431209575591408 > -0.70788987007807891 > 0 0 > 1.1020973480483873 > -1.5169068644530264 > 0 0 > 0.43749999999999994 > -0.75777222831138391 > 0 0 > 0.93749999999999989 > -1.6237976320958225 > 0 0 > 0.35589456269132536 > -0.79935227543727572 > 0 0 > 0.76263120576712584 > -1.7128977330798765 > 0 0 > 0.27038987007807908 > -0.83217445175825933 > 0 0 > 0.57940686445302658 > -1.7832309680534129 > 0 0 > 0.18192272946553939 > -0.85587915064207998 > 0 0 > 0.38983442028329873 > -1.8340267513758857 > 0 0 > 2.5 > 0 > 0 0 > -2.5 > 0 > 0 0 > [NumSegments] = 0 > [NumArcSegments] = 6 > 2 > 0 > 180 > 2 > 0 > 0 0 > 3 > 1 > 180 > 2 > 0 > 0 0 > 0 > 2 > 180 > 2 > 0 > 0 0 > 1 > 3 > 180 > 2 > 0 > 0 0 > 113 > 112 > 180 > 10 > 0 > 0 0 > 112 > 113 > 180 > 10 > 0 > 0 0 > [NumHoles] = 0 > [NumBlockLabels] = 3 > 0 > 1.375 > 2 > 0.050000000000000003 > 0 > 0 0 > 0 > 0.375 > 1 > -1 > 0 > 0 0 > 2 > 0.375 > 1 > -1 > 0 > 0 0 > > > [Non-text portions of this message have been removed] > > > > > > > > > > Yahoo! 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