Re: Magnifier conversion

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:

 > Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

 > I was thinking of making an add-on to convert my small coil into a
 > magnifier system:

 > I would just use my present secondary coil as a tertiary coil now.
 >
 > L1 = 21.5uH
 > C1 = 23.8nF
 > L2 = 3.97mH
 > C2 = 12.3 pF
 > L3 = 22.1mH
 > C3 = 18.5pF

With these values for C1, L3, and C3, the closest ideal mode that
I find is 3:4:5, that gives:

C1=   23.8000000000 nF
L1=   19.5835714286 µH
C2=  150.3492063492 pF
L2=    3.0940000000 mH
C3=   18.5000000000 pF
L3=   22.1000000000 mH
k12=     0.3504383220

The value for L1 can be compensated by adjusting C3:

C1=   23.8000000000 nF
L1=   21.4995857143 µH
C2=  165.0590476190 pF
L2=    3.0940000000 mH
C3=   20.3100000000 pF
L3=   22.1000000000 mH
k12=     0.3504383220

But L2 if fixed by the mode and by L3:
1:2:3: L2=18.4166666667 mH
2:3:4: L2= 6.0429687500 mH
3:4:5: L2= 3.0940000000 mH
3:4:7: L2= 5.7880952381 mH
4:5:8: L2= 3.7876464844 mH

In mode 4:5:8:
C1=   23.8000000000 nF
L1=   21.5041500419 µH
C2=   70.4059829060 pF
L2=    3.7876464844 mH
C3=   19.7700000000 pF
L3=   22.1000000000 mH
k12=     0.3825061606

By increasing the last multiplier, keeping its parity,
it's possible to adjust C2 to many values, ending with zero when
it tends to infinity. The other elements tend to a limit, that
is the magnifier with C2=0. The maximum voltage over L2 is maximum
in this condition (~1/3 of the output in this mode).
Your design is close to mode 6:7:infinity, but C2 is too high
to achieve it perfectly in  a lossless system. The losses in
your model may be adjusting the tuning to a correct condition,
however. Note that by increasing C2 and a few adjustments,
you can change the energy transfer from 3.5 cycles (6:7:inf)
to 2 cycles (3:4:5).

What I would recommend for a magnifier desing is to first fix L3 and
C1, then calculate L2 and the coupling from the desired mode.
L1 can then be adjusted by adjusting C3.
C2 and the coupling can be adjusted experimentally, by searching
a condition that decreases the voltages over L1 and L2 to zero
simultaneously at the first notch.
The program mrn6 is useful to quickly visualize what happens.
http://www.coe.ufrj.br/~acmq/programs

Antonio Carlos M. de Queiroz