[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

*To*: tesla-at-pupman-dot-com*Subject*: E-Tesla = Medhurst*From*: "Robert Jones" <alwynj48-at-earthlink-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)*Date*: Sun, 11 Jun 2000 12:13:44 -0600*Approved*: twftesla-at-uswest-dot-net*Delivered-To*: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Terry. After a little more thought or was it a lot more thought. For a large parallel C the voltage a long the coil approaches a linear function regardless of what the distribution is with out parallel C. ie the current flowing in the distibuted intrinsic C hardly effects the voltage across the coil because the coil current is much higher than the intrinsic C current. Hence the additional current flowing in to the distributed intrinsic C is only a function of the voltage and C. This is even true for low H/D (<0.25) with almost unity coupling (auto transformer action). Under such condition the distibuted intrinsic C can be refereed to one end by simple summing the currents. Because the currents are proportional to the voltage a voltage weighted intrinsic C is equal to a single C you must put in parallel with the coil to have the same total current flow that the distibuted intrinsic C had. Hence if you run E-Tesla with a linear voltage and on an isolated coil it will produce med C. This is a theoretically valid comparison and should correlate to approximately. 1% in C not F. A good test of the theory and model. If you run it with a ground plain it will produce med C with a ground plain. But as Medhurst did not produce such a table you can not make any valid comparison. The true C / TM equation is again theoretically valid for an isolated coil. When I say valid for..... I dont mean its not valid for other conditions it means only that I can only prove its valid for that condition/s. So E-Tesla can be said to be theoretically accurate for coils with approximately 1000 turns (low turn to turn C effects), for large top loads and with a ground plain sufficiently below the coil (at least several diameters) that the inductance is valid. Note E-Tesla must include some internal C (turn to turn C) effects because the C is determined with a voltage profile as opposed to a unity profile (the correct way to calculate intrinsic C) then weighting the result with the voltage profile. However as the internal C has mostly internal current I don't know if it can be refereed to the one end and I don't if how you treat the internal coupled flux is valid or correctly produces a reffered C to one end. That will require more thought but as I believe its a small effect I am not motivated to try. If you try it both ways and the answer (refereed C or med C) is significantly different then I will be motivated to try. Now what about the self resonant case. When the only current flowing in the coil is due to the distributed intrinsic C both the voltage and current are not linear so the above method of referring the intrinsic C to one end is not valid. A 5% to 10% error in F is 10% to 20% error in C or L. Regards Bob You can put this on the list if you think anybody else is interested -----Original Message----- From: Terry Fritz <twftesla-at-uswest-dot-net> To: Robert Jones <alwynj48-at-earthlink-dot-net> Date: Sunday, June 11, 2000 12:20 AM Subject: Re: Voltage profile on the secondary >Hi Bob, > >At 10:54 PM 6/10/00 -0400, you wrote: >>Hi Terry, >> >>Sorry I did not explain my self very well. What I should have should have >>said was: >>I was using the assumption that the voltage distribution is a sine wave but >>then your measurments indicate this is a very poor assumption. I was hoping >>that your measurments had some reason for why the sine wave had been >>modified so I could still use my assumption >> >>In the infinite length constant C case I am certain its a sine wave. It >>cant be anything else in a linear system.. >> >>The finite case depends on the distribution of the C and the decrease in >>coupling at the ends. I dont know the distribution so I can not give an >>answer even if I had corrected my error. >> >>Its some time since I did mechanics at collage. If I remember correctly for >>a thin ruler under its own weight the defection cubic because the angle is >>parabolic due to the bending moment being the product of the mass and >>distance. >> >>When you measured the coil was it above a ground plain or as isolated as you >>could get it? > >It was above a split foil ground plane. > >> >>The key problem with your voltage weighted C is that there is no theory to >>justify it (that I have seen). This does not invalidate it but it makes it >>very weak. >> > >I was hoping you could come up with that small detail ;-))) I have not >been able to find a good reason or a tie in to circuit theory to explain it >yet either. However, I have not seen any actual measurements to say it is >wrong but the measurements do not support a sine profile... I was >pondering if the capacitance could be linking just like the mutual >inductance in the coils and if that could somehow explain it. However, I >really have no idea why... > >Since the program works so well, there must be something to it. The >voltage profile is critical to getting the right answers. Of course, I may >have hit on some strange equivalent case. The program also gives the >Medhurst C instead of your true C to do all this. I wonder if setting the >voltages all to 1.0 and using the true C formula would work too? I'll >check into that.* > >Cheers, > > > Terry > >* The frequencies seem to come out low but only by about 5-10% Far closer >than I expected. Might be something to that... > > >>Regards Bob >> >> >> >> >>-----Original Message----- >>From: Terry Fritz <twftesla-at-uswest-dot-net> >>To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com> >>Cc: Robert Jones <alwynj48-at-earthlink-dot-net> > >

- Prev by Date:
**RE: copper plating** - Next by Date:
**Re: Resonator Self Resonant Frequency** - Prev by thread:
**Re: copper plating** - Next by thread:
**Re: E-Tesla = Medhurst** - Index(es):