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Re: Computer data
From: DR.RESONANCE[SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Sunday, August 31, 1997 9:33 PM
To: Tesla List
Subject: Re: Computer data
to: Greg
Thank you for the update. Will get to work on this later this week and
advise. Hope the information will be of assistance in your large project.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: Re: Computer data
> Date: Sunday,August 31,1997 7:33 PM
>
>
> From: Greg Leyh[SMTP:lod-at-pacbell-dot-net]
> Sent: Sunday, August 31, 1997 2:41 PM
> To: Tesla List
> Subject: Re: Computer data
>
> DR.RESONANCE wrote:
>
>
> > Even without CW the tank current will dip as noted on the primary side
> > ammeters. We did this experiment in Calif. in 1981 with Bill Wysock
> > running one of
> > his large coils -- I believe it was a model 10. The coil output was
around
> > 32 ft. long spark.
>
> Bill certainly has an unusual way of rating the performance of his coils.
He
> may be stretching things a bit to derive a 32 ft. arc length, at least
from
> the pictures shown in http://www.ocws-dot-com/tesla/model10.html.
> It appears that he measures the peak _diameter_ of the arc striking
range,
> rather than the actual arc length. This could explain the 55 ft. claims
made
> in the second photo at http://www.ocws-dot-com/tesla/model13.html. Tesla
also used
> this peak diameter measurement method at one point to measure the
performance of
> his Colorado Springs expmt, where he describes the arcs as being "50 ft
across."
>
> > The power supply was set up with a continuously
> > variable series inductor and a standard parallel variac stack. As we
ran
> > the power up thru the voltage variac in small increments we made small
> > adjustments to the series inductor. At almost any setting above 50%
power
> > level (the range we are most interested in) as one increased the variac
> > (voltage) the current would begin increasing as well. At some point as
the
> > power factor begins to correct back to unity (phase meter across input
> > line) the primary 240 vac side of the power supply will indicate a
5-10%
> > drop in the primary current to the power transformer. This is what I
refer
> > to as the most efficient point of operation. The current actually
"dips"
> > just like a plate milliammeter in a ham radio transmitter. It's not as
> > dramatic, but the effect is quite evident. From this point the voltage
> > variac is increased more and the primary current once again begins to
climb.
>
> I understand now what you mean by dipping the input current, by tuning
the
> effective _power factor_ of your system, not it's resonant frequency.
> I think that yours is the first attempt I've heard of to tune for optimum
> power factor! That is definitely a good capability to have, especially
if you
> are operating near the kVA limit of your feeder!
>
>
> [snip]
> > I might
> > suggest you incorporate several taps into your limiting inductor system
and
> > you will be able to "tune" your power supply as well as your resonance
> > points. A continuously variable inductor demonstrates these principles
in
> > dramatic effect but this would be a lot of work to construct for your
very
> > large system. A phase shift indicator illustrating where unity is
while
> > your system is running is a very valuable addition to your
instrumentation.
>
> Unfortunately the PF is not adjustable on my setup, as the HV power xfmrs
are
> switched directly onto the 480V mains without the use of variacs or
limiting
> inductors (power is controlled by rotary gap speed). However, on a DC
resonant
> charger the PF is usually well above 0.9, since the inductive reactance
of the
> charging inductor exactly cancels the capacitive reactance of the primary
> capacitor bank as seen by the HV xfmrs.
>
>
> > Regarding the data I posted .... does it agree with any of your
measured
> > values of current input vs spark length output for your old system with
the
> > 0.18 MFD capacitor???
>
> I cannot say for sure, since I measured my mains current at 480V 3-phase.
> However, if I assume that your mains current values are for 240V 1-phase,
then
>
> Your prediction - at 90 amps input (21.6kVA) x = 21 ft. long sec.
spark
> at 108 amps input (25.9kVA) x = 25.2 ft. long sec.
spark
> at 130 amps input (31.2kVA) x = 30.3 ft. long sec.
spark
>
> Observed (Bert Pool's Austin pics) at about 21kVA x = 20(avg) to
25(rare) ft.
> I would say that your data is in good agreement, for at least this one
data point.
>
>
> -GL
>
>