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New cap test run
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From: Chuck Curran [SMTP:ccurran-at-execpc-dot-com]
Sent: Thursday, June 11, 1998 2:43 PM
To: Tesla List
Subject: Re: New cap test run
Tesla List wrote:
>
> ----------
> From: Esondrmn-at-aol-dot-com [SMTP:Esondrmn-at-aol-dot-com]
> Sent: Tuesday, June 09, 1998 10:21 AM
> To: tesla-at-pupman-dot-com
> Subject: New cap test run
>
> Well, I fired up the coil last night with the second .025 mfd cap in parallel
> with the first - for a total of .05 mfd. The safety gap across the caps was
> set to .50". I had calculated best tune to be at turn 8.0. It actually is at
> turn 8.5. With 3.3 ohms of resistive ballast in series with a 5000 watt
> variac used as inductive ballast, I had 28 amps of primary current and primary
> pole transformer input voltage of 200 volts. The system ran good with best
> discharges to a grounded wire of about 72".
>
> I tried changing from 3.3 ohms to the new 2.4 ohm resistor array and at max
> power the system was some what erratic. Primary current was 35 amps bouncing
> up to 45 amps. Switched back to the 3.3 ohm resistors and changed the variac
> tap from the 240 volt output to the 280 volt output. What a difference - we
> had long sparks all over the place. I had a wire extending about 2.0" off one
> side of the toroid, aiming toward a grounded wire target. From this point, I
> had 75" plus sparks to the ground wire but also had multiple breakouts all
> over the toroid, some as long as the ones leaving from the wire. Had several
> hits to the strike rail, must have had a couple into the primary also since
> the main safety gaps fired a few times. Primary current was 35 amps with the
> transformer primary voltage at 250 volts (8.75 kva). Also had hits down to the
> concrete driveway. This is the first time this coil has had strikes that hit
> the earth. The cap safety gaps never did fire! This is great as that was my
> major problem a month ago.
>
> Based on the big increase in performance gained by going to the 280 volt tap
> on the variac, it kind of makes me want to open up the pole transformer and
> find the next higher voltage tap - maybe. Next run I will try using both
> toroids, the 40" on the bottom with the 33" raised up above it about 12".
> This works good on my smaller coil to keep the sparks from hitting the
> primary.
>
> I know there are several other 6.0" dia coils out there. What kind of
> performance have you achieved? My secondary winding length is 27.6" so I am
> getting sparks that are 2.7 times as long as the secondary.
>
> Finally happy in Spokane, Ed Sonderman
Ed:
It's great to hear that you have good results to tell all about. You
did put alot of work into resolving the earlier difficulties, so I'm
happy that you were successful! For what it's worth, my 1996 coil is
one with an 8" diameter secondary with a 28" winding, somewhat similar
to your unit. I have been using my stove element resistors in parallel
with the inductance and that has also worked well. I was able to tune
at lower voltage and then I always ran it at 280 volts too as you have
chosen to do. I monitored the voltage at the input to the pole
transformer and the 300 VAC Simpson meter would oscillate/vibrate while
pegging the meter full scale due to the inductive kick back in the
current limiting inductor. I'm at work (lunchtime) so I don't have my
notes here but I believe I ran at about 30 amps for 8+ Kw resulting in
80" plus spark length. This system uses a 40" x 5" toroid if my memory
is any good!
Again, glad to hear of your success, keep it up!
Chuck Curran