RE: Designing High-Gain Triple Resonance Tesla-Transformers

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Day, Michael" <Michael.Day-at-USPTO.GOV> 



 >It's possible, however, to make a magnifier driver with quite
 >high coupling by using a flat primary coil and a short
 >solenoidal coil. To increase the effective coupling, the bottom
 >of the secondary coil can be connected to the top of the primary
 >coil (ground the outer end of the primary coil, and connect the
 >inner end to the bottom of the secondary coil, both wound in the
 >same direction). Make the primary coil conical, and coupling
 >coefficients around 0.7 can be easily obtained.

Most solenoid coils that I have seen having such high coupling
coefficients appear to be vulnerable to HV breakdown at the final
turns of the secondary windings.

The spiral strip transformer, on the other hand, produces
uniform voltage grading through the thickness of the secondary
winding.  The equal potential lines outside the windings, however,
bend sharply around the edges of the thin winding conductors
creating highly enhanced electric fields which results in electrical
breakdown.  The function of the ring cages is to maintain the coaxial
field distribution across the margin which is nearly parallel to the
uniform field throughout the thickness of the winding.

The outer cage appears to be connected to the primary turn.  FIG. 7 of
U.S. patent No. 5,079,482 provides a clear illustration of an outer
cage.  It is not clear to me how an inner ring would be connected.

  >> To date, the only resonant transformers that I have seen having
  >> such high coupling coefficients have been of the spiral strip
  >> design that include inner and outer ring cages to shape the
  >> electric field in the margins of the transformer.  (See, for
  >> example, IEEE Transactions on Nuclear Science, Vol. NS-26, No.
  >> 23, June 1979, pp4211-4213.)  What is not clear to me in the
  >> spiral strip design is how the ring cages are connected.  That
  >> is, are the ring cages connected to their respective inner and
  >> outer winding?

 >Couldn't find the article. Too old to be on the IEEE site.

The article gives the best description I could find.  The description
would indicate that the inner cage rings have significant differences from
the outer rings.  I have other references that illustrate ring cages in
pulse transformers, however, they do not provide much of a description.

If the inner ring cage is merely to control the equipotential lines in
the transformer margin, then might they not be left floating?

Mike Day