Re: What's around the toroid is important....

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

Original poster: "Jeremy Scott by way of Terry Fritz <teslalist-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>


For this setup, I would do this: (hypothetically)

Secondary coil, coupling and toroid are fixed
values. Their resonant frequency is calculated
either mathematically or by ye olde TCT or
another method offline before power-up.
A "target frequency" is set.

A frequency counter with RS-232 output should peg the
current resonant frequency of the tank and
send it to the basic stamp, which will know what
the secondary 'target' frequency will be. The stamp
will figure out if the primary inductance is too
high or low and signal the motor to move the tap
accordingly.

After this is done, the stamp begins to read the
field strength from the meter and slowly rotates
the phase of the spark gap until the peak is reached.
This could optionally involve turning the variac up
while simultaneously adjusting the spark gap phase.
(Since input voltage affects capacitor charge time)

The first step, which I'm working on now, is to write
the program with simulated 'parts' and inputs.
The code that determines the 'tap' point in the
primary
is already written. (Similar to that found on JavaTC)
and can works as 'left' 'right' 'stop' logic.

I'm not entirely worried about a PC being near or
underneath the coil -- with proper sheilding it should
be immune. Fun things to do would be to hook it into
802.11b wireless network (provided it can cut through
the RF coil field) and have it report statistics to a
website :)

The key here is finding an RF Frequency Counter and
Field Strength meter that can output an RS232 signal
that can be used with anything, not just their
properietary software. Ideally it would be a combo
card that would fit inside a PC and be programmable
from linux :)





--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
 >
 > Hi Jeremy,
 >
 > At 03:52 PM 5/8/2003 -0700, you wrote:
 >
 > > > >Calculated Resonant Frequency: 215.24kHz
 > > > >Measured Resonant Frequency: 214.3kHz
 > > > >(The meter has a +- tolerance (1 or 2%) ... )
 > > >
 > > > It has gotten to the point that the programs and
 > > > calculations are more
 > > > accurate than most meters :-))
 > >
 > >Yes, one day, a Basic Stamp will tune coils
 > >in real time :) I'm desiging a coil with a
 > motorized
 > >primary tap, motorized spark gap adjustment and
 > >motorized variac. I'm not sure if I want to use a
 > PIC,
 > >basic stamp, or a cheap 486 PC to drive the
 > >motors/feedback system. Probably a PC since they're
 > >cheap and easy to program. I wrote a perl module to
 > >do all the calculations, the next step is getting
 > >real world measurments a) safely and b) analog to
 > >digital. Kind of like a robotic coil :)
 >
 > Cool!!!
 >
 > One thing to think about is how the coil's fields
 > will be wildly picked up
 > on control lines and such to the PC and other remote
 > equipment.  All those
 > antenna's...  You could do all kinds of fiber optic
 > stuff or filters
 > everywhere...  But really, a small local shielded
 > Basic Stamp thing may be
 > the best way to go just from a keep it simple noise
 > control standpoint.  In
 > fact, each device may be able to have it's own
 > little controller if you can
 > get them the feed back signals they need to adjust
 > to an optimal setting
 > locally.  The primary tap for biggest sparks
 > received on a small antenna,
 > the gap for highest firing voltage.  The variac for
 > how lucky you feel ;-))
 >
 > Cheers,
 >
 >          Terry
 >
 >
 >
 >
 >
 >


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