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RE: NST TEST GRAPHS (was NST power test)
Original poster: "John H. Couture by way of Terry Fritz <teslalist-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
Jim - Refer to replies below. JC
------------------------------
-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, January 17, 2003 8:43 PM
To: tesla-at-pupman-dot-com
Subject: RE: NST TEST GRAPHS (was NST power test)
Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>
Does any of this testing show that a simple transformer model (leakage
reactance, series resistance, magnetizing inductance, loss resistance)
doesn't adequately describe the NST operating in it's linear (non
saturated) regime?
------------------
None of my testing indicates that this changes. However, the tests did show
that if the load is only a varying resistance the sec voltage is linear but
the sec wattage is non linear. Also, the tests did show that if there is any
capacitance in the NST loading the curves are always non linear. The graph I
showed on the my site was for loading with capacitors only. There was a
small amount of active load in the VA of the graph. To simulate a Tesla coil
load I made a test with a .01623 uf capacitor (pri cap?)in series with
varying resistances (different streamer lengths?). This gave a larger active
load. The graph showed two non linear curves that intersected. At the
intersection (equal power) of the curves there was a maximum for both the VA
and watts. I took this to be the point of optimum operation and maximum
overall efficiency for this type of loading on this particular NST.
-------------------
I don't know that the intersection point is truly where power in=power
out... it IS where apparent power (VA) is equal, but given that you've got
a reactive load, it doesn't say much about real power.
--------------------
The real power for the capacitor only load is small but see above for when a
larger active load is involved.
---------------------
When the secondary VA is greater than the primary VA, it just means that
there is reactive power circulating in circuit formed by the secondary
leakage inductance, resistance, and the external capacitor. In fact, it's
a good indication of resonant rise in the secondary, since that would
nicely explain it.
0.01 uF at 60 Hz would be about +j265K ohms...
7.5kV open circuit with 30 mA short circuit output current would imply that
the leakage inductance has a reactance of about -j250K... (neglecting the
iron and copper losses, which are probably around 5-10%)
So, the 0.01 uF case is pretty darn close to resonant. What was the
voltage across the capacitor in this case?
-------------------
Unfortunately, I did not have a variable uf capacitor to look for resonance
around .0106 uf. There was no voltage rise at .008 uf and the sec voltage
was 5700 volts. There was also no voltage rise at .011 uf and the sec
voltage was 6200 volts. If there is a voltage rise between .008 and .011 I
would expect that the tuning would be very sharp.
--------------------
At 04:49 PM 1/17/2003 -0700, you wrote:
>Original poster: "John H. Couture by way of Terry Fritz
><teslalist-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
>
>
>Terry -
>
>I was pleased to hear you are doing similar NST tests that I have done. So
>far I have not been able to verify my NST test results. Apparently this is
>new territory for most coilers. I was surprised that you did not find that
>the cap load on your NST did not show a VA output greater than the VA
input.
>I believe this was due to your test setup. I suggest you change your
>schematic by eliminating the resistance and omitting the ground connection
>to the caps. When you add resistance it should be in series with the cap.
>
>Your NST should be a HPF type with a built-in cap, not the added on caps.
>The KV voltmeter should be an electrostatic type. Only 120 VAC for the NST
>input is needed. Varying this voltage is not required as in Hull's tests.
>These changes should give you graphs similar to the ones I obtained. If
>possible, measure the input volts (120), amps, watts, and calc the VA and
>power factor. Measure the output KV (electrostatic), milliamps, and calc
the
>VA, and watts. Make graphs with load (uf, ohms) as X axis and VA, or other
>secondary variable as Y axis.
>
>One of the many graphs I made is shown at
>
> http://www.mgte-dot-com/tesla/rc-neon-curve.pdf
>
>An Acrobat printout gives a clearer view than the screen. This graph shows
>the VA input and VA output curves when a capacitance load on the NST is
>varied from .002 to .014 uf (X axis) and the Y axis is 40 to 200 volt amps.
>Note that these curves intersect at an important point on the graph. This
>condition is when the Power Input exactly equals the Power Output. Do not
>confuse power with energy because this condition with energy would have to
>include losses.
>
>My other tests were with combinations of both capacitors and resistors. The
>graphs all showed non linear curves of varying shapes. Sometimes the curves
>intersect and sometimes they do not. The intersect points are very
important
>because they appear to be optimum operating conditions with maximum overall
>efficiency for a particular type of load. I believe this is something new
to
>coilers. There is much more testing of this type to do.
>
>John Couture
>
>------------------------------
>
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Wednesday, January 15, 2003 8:15 PM
>To: tesla-at-pupman-dot-com
>Subject: RE: NST power test
>
>
>Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
>
>Hi John,
>
>I have been doing tests too :-)) Although still very rough draft like, it
>is at:
>
>http://hot-streamer-dot-com/temp/NSTva.html
>
>It is not done yet, but I thought I would mention it now for
>suggestions. I could only get 260VA out of a 360VA NST using just
>caps. Any ideas are welcome ;-)) It is all set up and just waiting.
>
>Cheers,
>
> Terry
>
>At 11:43 AM 1/15/2003 -0500, you wrote:
>
> >To All -
>
>-------------------- big snip ------------------