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Re: [TCML] Magnifier topics
Thanks for the Link Below! Been looking for this circuit for a while!
Cheers
j.
On Sun, 21 Feb 2010 19:03 -0500, "David Sharpe" <sparktron01@xxxxxxxxx>
wrote:
> Hi Finn
>
> On Sun, Feb 21, 2010 at 4:23 AM, Finn Hammer <f-h@xxxx> wrote:
>
> > David Sharpe skrev:
> >
> > L2 has been designed in coordination with new flux concentration
> >> primary design. Once I get details fleshed out,
> >>
> > David,
> >
> > What you mention here, the flux concentration design, is new to me, and
> > sounds interesting.
> >
> > Since the thread is in a dormant state, these last couple of days, I wonder
> > if you could enlighten me about the theory behind this scheme.
> >
> > Eddy current concentration (Flux concentration), has been used by the
> induction heating industry for over 60 years.
>
> Several examples of the IDR driver / eddy current flux concentration
> principle are listed below...
>
> http://www.google.com/patents?id=XX9jAAAAEBAJ&pg=PA1955&dq=vacuum+tube+induction+heating+current+concentraor&source=gbs_selected_pages&cad=2#v=onepage&q=&f=false
> Particularly Figure 1, in this case a solenoidal primary driving the
> ECFC
> to heat small diameter conductive targets
>
> http://www.google.com/patents?id=s9ZMAAAAEBAJ&pg=PA1&dq=vacuum+tube+induction+heating+current+concentraor&source=gbs_selected_pages&cad=2#v=onepage&q=&f=false
>
> http://www.google.com/patents?id=2XdeAAAAEBAJ&pg=PA1&dq=2847651&source=gbs_selected_pages&cad=2#v=onepage&q=2847651&f=false
>
> 2847651 intrinsically validates concept is workable with pancake coils.
> In
> my case there will be two pancake coils on either side of the ECFC
> and there will be 1/4" aluminum busbar welded to the ID of current
> concentrator slug. The ID of ECFC drives L2 (Tesla Coil/Driver
> secondary).
>
> Secret is current is induced in area of washer is reverse direction of
> exciting current (Lenz's Law). However once this sheet current hits the
> radial
> slot, in flows radially inward to lowest resistance path which is the ID
> of
> the ECFC. This concentrated current now flows in same direction (in
> phase)
> with pancake primary excitation current. At a barebones minimum most
> pessimistic case, I am increasing the coupled amp-turns in to L2 coil.
> If
> coupling was perfect, and no losses in IDR ring, boosted magnetic field
> would be DOUBLED (magnetic mirror effect) with no net power increase
> required.
>
> So what is the advantages? Well looking at thelater patent it is obvious
> that:
>
> 1. Highest voltages are on OD of pancakes, where radius of curvature is
> maximum. That will allow HV operation with minimal leakage or flash over
> hazard,
> especially if a shallow "bowl" primary is used (included angle 10 deg
> <
> x < 30 deg)
>
> 2. ID of pancakes are connected in series, effectively paralleling
> current
> sources to plate. Yes the IDR will get warm/hot. However by wiring ID
> of
> primaries
> near ID of current concentrator, diametrically opposite of radial
> slot,
> will dramatically reduce the voltage between the L1 primary/IDR and the
> L2
> driver secondary. I can now run extremely close radial spacing
> between
> L1/IDR and L2 with minimal risk of flashover, even if I am using 30kV or
> more in the tank circuit.
>
> 3. I can now adjust the vertical alignment on axial centerline of the
> pancake primaries to the IDR ring which gives effective control of L1
> inductance,
> coupling to L2 and IDR, and thereby coupled current to L2. This
> methodology also allows very precise, repeatable frequency tuning control
> without effecting bang size.
>
> 4. Furthermore, I can adjust vertical height of L2 independently in
> relation to L1. So it is a fully adjustable primary geometry.
>
> The key: It is a RF ground referenced CURRENT DRIVEN system, with a
> source
> impedance < 0.1 ohm.
>
> The only possible fly in the ointment is I may OVERCOUPLE L2 and start
> getting racing sparks. If that happens, I simply decouple the system
> by raising L2 as required to stop the breakdowns.
>
> The reason I ask is, that my gut feeling says this aluminum slug is going
> to
> > get mighty hot, due to eddy current losses.
> >
>
> Understood, but it can be force air or even water cooled in high power
> applications. Also understood that it will be an additional loss term
> that
> will be tricky to characterize.
>
> >
> > Cheers, Finn Hammer
> >
> >
> --
> Dave Sharpe, TCBOR/HEAS
> Chesterfield, VA USA
>
> Sharpe's Axiom of Murphy's Law
> "Physics trumps opinion!"
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