Re: tuning in my latest big coil (a little long)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: DRIEBEN@xxxxxxxxxxxxxxx 

Hi Ed,

Thanks for the input. I'm really thinking my issue
was probably more of a quenching problem than a re-
sonance one, though. It only happened as I started really
pumping the power to it (70 on the 0-100 scale of the
0-280 volts/56 amp twin 1256D variacs) and I had not
fully fine tuned it at this point yet. It seemed that as
I started to get the tuning more keen this problem
began to deminish. As I stated, the rotary gap components
got really HOT after just a minute or two of operation.
Bert Pool suggested to me off list to add a stationary
gap of three or four 2.5"x4" long copper pipe sections
in series with my main rotary gap and I may try this
avenue if this problem recurrs at the next time I try
firing it.

David Rieben

----- Original Message -----
From: Tesla list <tesla@xxxxxxxxxx>
Date: Wednesday, May 4, 2005 12:33 pm
Subject: Re: tuning in my latest big coil (a little long)

> Original poster: Esondrmn@xxxxxxx
>
> David,
>
> Congratulations, that coil should be a real good performer.  I
> want to
> caution you about that popping noise you are describing coming
> from the
> rotary gap.  It sounds just like the 60 hz resonance problems that
> I used
> to have with my coil when using a welder for ballast for the 5 kva
> 14.4 kv
> pig.  If you don't already have one, I strongly suggest you put a
> safety
> gap across the rotary gap.  I originally used bare # 10 copper
> wire bent
> with 1.5" diameter loops on the ends, set to .625" and it fired
> loud and
> often.  After changing the ballast and resetting the gap to .50",
> it never
> fires now.
>
> Ed Sonderman
>
>
> In a message dated 5/2/05 7:23:30 PM Pacific Daylight Time,
> tesla@xxxxxxxxxx writes:
> Original poster: DRIEBEN@xxxxxxxxxxxxxxx
>
> Hi all,
>
> I had a chance to try to tune in my newest big coil
> project yesterday afternoon (Sunday) along with lo-
> cal HV enthusiast and fellow Tesla list member Carl
> Litton. We pulled it out in the driveway although I
> don't think that we pulled it quite far enough from
> the house :^O Anyway, we played around with tuning a
> little while before we started getting anthing off of
> the breakout point of the 12x56 toroid. We finally de-
> cided that .2 uFD was just too much capacitor for my
> 15 kVA transformer to effectively charge that fast
> from my 60 amp electrical service. So we removed one
> of the two .1 uFD, 50 kV pulse caps and started trying
> to run with just one. Things started improving at this
> point ;^) We started getting streamers with the primary
> tapped between the 10th and 12th turn (there is only 12
> turns on the entire primary). A little more tweeking
> seemed to narrow the best tuning down to the 10th to
> 10 1/2th turn of the primary. The primary is 12 turns
> of 5/8" OD copper tubing in a spiral with approximately
> 1/2" turn/turn spacing and the innermost turn at 15" in
> diameter and the outermost turn at about 40" in diameter.
> The secondary is 1260 turns of #19 magnet wire wound on
> 48 1/2" of a 12.75" OD gray PVC duct pipe. The spark gap
> is an asynch rotary type with infinte speed adjustment
> from 0 - 3500 rpm via a variac and a FWB rectifier. The
> ASRSG has 8 rotary electrodes and 2 stationary electrodes.
>
> We were really starting to get her toward the sweet spot when
> mama couldn't take it anymore and told me that I had to
> stop. Toward the end though we were starting to get ground
> strikes from the toroid and it's over 7 ft off the ground ;^)
> I never turned my variac knob up past about 70 either (0 to
> 100 scale where 100= 280 volts) One thing that I did notice
> is that the RSG started to quench poorly when I turned the
> variac up to around 70 (an erratic popping sound with visi-
> ble change in the RSG spark) That's one of the main reasons
> that I didn't turn it up past 70! Toward the end though as
> the tuning started to get more keen it seemed that the
> RSG didn't have as much trouble quenching and it ran better
> even as the varic got turned up closer to 70. It was at this
> time that mama "laid down the law" though so we weren't able
> to completely "tune 'er in for the sweet spot":*( I assume that
> it is normal for the spark gap to have more trouble quenching
> when the coil isn't properly tuned but does quench better once
> properly tuned, right? And man do the 1/2"x3" long tungsten
> carbide stationary electrodes and their accompanying 1 1/4"
> brass square stock mouting hardware get HOT!!! I'm sure
> that tends to make quenching a bit of a challenge, too!
>
> I found out later that my garage door opener is now defunct :^(
> and I'm sure it's no coincidence that it was following the
> firing of the big coil :^O That's why I stated earlier that
> we didn't set the coil up far enough away from the house!
> We may try moving the coil to Carl's place for the next firing
> as his facilities seems a little more "EMP friendly" than do
> mine :^P We're hoping for 12 ft to 14 ft+ once everything is tuned
> in ;^)))
>
> David Rieben
>
>
>
>
>