Nobody wrote that LC tanks are unavoidable when making a rotating field, that's your imagination. LC tanks are just the most efficient method for achieving high power levels. In any other method than LC tank pumping, all of the energy in the coils needs to be sourced/sinked by an external amplifier. In other words, if you wanted 1kA in your coils then your amp must be able to deliver it from outside (unless you're using pumped LC tanks). Also, with LC tanks, sinewaves come out naturally, in other methods you have to synthesize them externally. George At 03:24 2004/02/12, you wrote: >What's this nonsense about needing LC tanks to make a rotating magnetic >field? If someone blew his amplifiers, that's not because he didn't >have self-resonant LC tanks, but because of an IMPEDANCE MISMATCH. > >Let him complicate things if he can't impedance match his coils, but we >who know about impedance don't need no LC tanks. > >Jaro > >-----Original Message----- >From: George Robinson >To: jlnlabs@yahoogroups.com >Date: Wednesday, February 11, 2004 10:42 AM >Subject: Re: [jlnlabs] ROTATING MAGNETIC FIELD > > >> >>You're correct that the phase difference between voltage and current >in a RLC circuit is not perfectly 90deg, but this deviation is >insignificant in MagVid. As a curiosity, the self-oscillating >frequency depends a little on the resistance as well. >> >>If we write that R is Resistance, L is Inductance and C is the >capacitance of out RLC circuit, then: >> >>Damping factor (d): >>d=R/2L >> >>Self-oscillating frequency (f): >>f=SQRT( (1/LC) - (d^2) ) >> >>The V-I phase difference is equal to: >>pi - ATAN(f/d) >> >>Let's plug in some real world values of R=9Oohms, L=100mH, C=1uF and >we get a V-I phase difference of 90.815 >>deg, so let's not split hairs over the 0.815 of a degree. >> >> >>Anyway, even 5deg. deviation would still give pretty well rotating >magnetic field in MagVid. >> >>George >> >> >> >> >>At 19:57 2004/02/10, you wrote: >> >>>--- tmaniac999 wrote: >>>> > The second method takes advantage of a natural >>>> 90deg. phase >>>> relationship between voltage and current in an >>>> oscillating LC tank. >>>> Just build a tunable LC tank and convert the current >>>> into voltage (or >>>> voltage into current) and you get 2 sinewaves 90deg >>>> out of phase. >>> >>>There is a common misconception that an inductive >>>reactance current is 90 degrees out of phase with its >>>source voltage. That condition ONLY applies for the >>>IDEAL case scenario which would exist if the inductor >>>had no resistance. In the meantime, the REAL inductor, >>>if it is of appreciable inductance, only tends to >>>APPROACH that 90 degree phase angle, but never >>>actually gets there because of the REAL world quantity >>>of its resistance. In the real world the only >>>inductors that approach this 90 degree phase angle >>>within 5% of that ideal would be components of a >>>ferromagnetic transformer, or large ferromagnetic >>>chokes. In the meantime I will give two comparisons to >>>show what I am speaking of. The first of these would >>>be a large 1000 ohm induction coil of 20,000 winds of >>>23 gauge wire, which is a large spool of 80 lbs of >>>wire, which we know then to be a huge inductance, >>>therefore we suspect that its reactive currents at 60 >>>hz will be near that 90 degree phase angle. Next I >>>will compare this to a 1.2 ohm 500 ft spool of 14 >>>gauge wire at only 11 mh being driven at 480 hz by a >>>AC converted alternator. Can one guess which of these >>>items is nearer to a 90 degree phase angle? Naturally >>>we would guess that the large induction coil, being >>>some 60 henry driven at 60 hz would be the correct >>>answer. But guess what, that is the wrong answer! Thus >>>we need to re-evaluate our understanding of so called >>>90 degree reactance currents to find out why the >>>commonsense answer is NOT the correct one. >>> >>>The reactive phase angle that assumes itself is the >>>angle made by the vector addition of the induction >>>reactance Y coordinate to the X coordinants resistance >>>value. For the case of the 60 henry coil I will not >>>use calculations to find the reactance, instead I will >>>use the simpler reactance current data, which shows >>>that it consumes 6 ma @ 120 volts AC. For these cases >>>where X(L) >> R, we can estimate X(L) as Z. The Y >>>inductive reactance coordinant for this case will be >>>approximated as V/I = 120/.006 = 20,000 ohms. Compared >>>to the X coordinant of 1000 ohms resistance, we can >>>see that these axis values predict something near a 90 >>>degree angle. But let us find the exact value by >>>trigonometry. To do this we have the Y/X vaue of 20. >>>This tells us that the answer is the angle where the >>>tangent will equal 20, or for this inverse trig >>>function, tan-1 (20) = 1.52 That answer is given in >>>radians, so we must multiply by the conversion factor >>>of 360 degrees/2 pi radians to obtain [1.52 * >>>360]/6.28 = 87.18 degrees. Thus even with this vast >>>inductance we are still ~3 degrees away from being a >>>perfect 90 degree phase angle. >>> >>>Now let us take the eaxmple of the 11 mh inductor @ >>>1.2 ohms being driven at 480 hz. Here we will use the >>>actual eqation of X(L)= 2 pi*F*L >>>X(L)= 6.28*480*.011 = 33.16 >>>tan-1 (33.16/1.2) = 1.53 >>>[1.53*360]/6.28 = 87.97 degrees >>> >>>Thus here we can see the dramatic effect frequency has >>>on the equation. Since the Q factor of an inductor is >>>also expressed as X(L)/R, we can say the higher the Q >>>factor of an inductor, the more it resembles a 90 >>>degree reactance phase angle. The purpose of all this >>>here is to show that for many cases at 60 hz, we may >>>not even be near an actual reactance phase angle of >>>only 45 degrees. It takes quite a bit of (real >>>world)inductance just to get that much of a phase >>>angle deviation, where at 45 degrees the inductive >>>reactance would equal the actual resistance of the >>>inductor being measured. Perhaps all of this is a >>>little irrevalent for the magvid cases, where a high >>>input frequency is already being observed, thus a >>>close resemblance to an actual 90 degree phase angle. >>>But it is still usefull to understand that this 90 >>>degree phase angle is never actually attained to, and >>>that the actual results are only close approximations >>>of that angle. >>> >>>Sincerely HDN >>> >>> >>>===== >>>Tesla Research Group; Pioneering the Applications of Interphasal >Resonances http://groups.yahoo.com/group/teslafy/ >>> >>> >>> >>>Messages archives at : >>> >>>http://groups.yahoo.com/group/jlnlabs/ >>> >>>To unsubscribe, send a blank email to jlnlabs-unsubscribe@egroups.com >>> >>>JLN Labs web site at: http://www.jlnlabs.org >>>Yahoo! Groups Links >>> >>> >>> >>> >> >> >> >> >>Messages archives at : >> >>http://groups.yahoo.com/group/jlnlabs/ >> >>To unsubscribe, send a blank email to jlnlabs-unsubscribe@egroups.com >> >>JLN Labs web site at: http://www.jlnlabs.org >>Yahoo! Groups Links >> >> >> >> >> >>--- >>[This E-mail scanned for viruses by Surfside Internet] >> >> > > > > >Messages archives at : > >http://groups.yahoo.com/group/jlnlabs/ > >To unsubscribe, send a blank email to jlnlabs-unsubscribe@egroups.com > >JLN Labs web site at: http://www.jlnlabs.org >Yahoo! Groups Links > > > >