Re: Arc welder as pig ballast not working right

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gregory Hunter <tesla_39560@xxxxxxxxx>

More than once I have seen Tesla coil streamers get
shorter as the power is turned up. This bass-ackwards
condition may be due to a poor quenching spark gap. At
reduced power, the gap can barely cope. As the PSU
current is increased, the gap begins to power arc and
streamer production diminishes. This is a simple thing
to test. Just place an air-blast static gap in series
with your RSG. If streamer production increases,
you've nailed it.

Cheers,

Greg


--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "seanick" <edgarsbat@xxxxxxxxxxx>
>
> Greetings, Coilers of the world...
> I bring to you a conundrum, or at least something
> which makes no sense to me. I have an 8" coil run
> by 10 KVA pig and a large old arc welder which
> has 10 or 12 different places to attach the
> leads, plus 2 ground choices. I have noticed
> lately that when I use the lowest power setting
> it works great, however at any other setting past
> that, my coil does not run continuously but
> becomes staccato and has much reduced output. I
> am using a synchronous rotary (@3600 rpm) with 4x
> 3/16" tungsten rotating electrodes and two
> stationary electrodes at 180 degrees offset,
> which are both adjustable remotely while the coil
> is running similar to Bart Anderson's rotary;
> adjusting the phase for the different power
> levels does not result in longer arcs than with
> the lowest setting though. I am only getting
> something like 4 feet which is WAY too low for the
> components I am using.
>
> The ballast at the lowest setting draws 17 amps
> when in series with the pig, and 50 at the
> highest setting, according to a clip-on ammeter.
> The arc welder itself works as expected; each
> higher setting results in more heat at the weld.
> What could cause this behavior? So far I only
> have two theories but I doubt either of these are
> the problem...
> 1. Quenching of the gap - reason I think this
> might be it is that I threw an electrode with an
> earlier revision of this gap. I have since
> installed aluminum sleeves with set screws to
> hold the electrodes. this seemed to cure the
> problem; now the electrodes are not even all that
> warm right after a relatively long run.(15 minutes
> of tuning cycles...)
> 2. power factor? I don't really know, this is
> grasping at straws.
>
> What could be the problem? has anyone ever
> experienced this sort of problem before? It
> baffles me, because I have never had so much
> trouble getting a long arc before. NST's and
> MOT's both outperform this pig, yet I know the
> pig is good and I can pull huge power arcs from
> it. I weld with the same welder, and have used it
> as the MOT ballast with much success until the MOT's
> burst into flame...
>
> Thanks in advance for any suggestions you can give!
> SeaNICK
>
> here is some of the data generated by
> classictesla, it saves me from typing it all in
> manually and has a formatted output.. thanks Bart
> for the consolidate function!
>
> J A V A T C v.10 - CONSOLIDATED OUTPUT
> Wednesday, August 10, 2005 08:57:36
> Units = Inches
> ----------------------------------------------------
> Secondary Coil Inputs:
> 4.125 = Radius 1
> 4.125 = Radius 2
> 27.5 = Height 1
> 75.5 = Height 2
> 1190 = Turns
> 18 = Wire Awg
>
> ----------------------------------------------------
> Primary Coil Inputs:
> 5 = Radius 1
> 8.15 = Radius 2
> 24 = Height 1
> 24 = Height 2
> 9.45 = Turns
> 0.25 = Wire Diameter
> 0.04 = Primary Cap (uF)
> 0 = Desired Coupling (k)
> ----------------------------------------------------
> Top Load Object Inputs (dimensions & topload or
> ground connection):
> Toroid #1: minor=9, major=27, height=82.5, topload
> ----------------------------------------------------
> Secondary Outputs:
> 121.01 [kHz] = Secondary Resonant Frequency
> 90 [deg°] = Angle of Secondary
> 48 [inch] = Length of Winding
> 24.8 = Turns Per inch
> 0.00003 [inch] = Space Between Turns (edge to edge)
> 17 [awg] = Recommended Wire Size
> 2570.2 [ft] = Length of Wire
> 5.82 = H/D Aspect Ratio
> 16.41 [ohms] = DC Resistance
> 34435 [ohms] = Reactance at Resonance
> 34919 [ohms] = Forward Transfer Impedance
> 12.64 [lbs] = Weight of Wire
> 45.29 [mH] = Les-Effective Series Inductance
> 43.841 [mH] = Lee-Equivalent Energy Inductance
> 47.143 [mH] = Ldc-Low Frequency Inductance
> 38.194 [pF] = Ces-Effective Shunt Capacitance
> 35.954 [pF] = Cee-Equivalent Energy Capacitance
> 58.107 [pF] = Cdc-Low Frequency Capacitance
> 7.479 [mils] = Skin Depth
> 27.287 [pF] = Topload Effective Capacitance
>
> ----------------------------------------------------
> Primary Outputs:
> 120.77 [kHz] = Primary Resonant Frequency
> 0.2 [%] = Percent Detuned
> 0 [deg°] = Angle of Primary
> 32.53 [ft] = Length of Wire
> 0.083 [inch] = Average spacing between turns (edge
> to edge)
> 0.875 [inch] = Primary to Secondary Clearance
> 0.064 [k] = Coupling Coefficient
>
> ----------------------------------------------------
> Transformer Inputs:
> 240 [volts] = Transformer Rated Input Voltage
> 13800 [volts] = Transformer Rated Output Voltage
> 725 [mA] = Transformer Rated Output Current
> 60 [Hz] = Mains Frequency
> 240 [volts] = Transformer Applied Voltage
> 17 [amps] = Transformer Ballast Current
>
> ----------------------------------------------------
> Transformer Outputs:
> 10005 [volt*amps] = Rated Transformer VA
> 19034 [ohms] = Transformer Impedence
> 13800 [rms volts] = Effective Output Voltage
> 17 [rms amps] = Effective Input Current
> 4080 [volt*amps] = Effective Input VA
> 0.1394 [uF] = Resonant Cap Size
> 0.209 [uF] = Static gap LTR Cap Size
> 0.3634 [uF] = SRSG LTR Cap Size
> 461 [uF] = Power Factor Cap Size
> 19513 [peak volts] = Voltage Across Cap
> 68979 [peak volts] = Recommended Cap Voltage Rating
> 7.62 [joules] = Primary Cap Energy
> 592.3 [peak amps] = Primary Instantaneous Current
> 92.3 [inch] = Spark Length (JF equation using
> Resonance Research Corp. factors)
>
> ----------------------------------------------------
> Rotary Spark Gap Inputs:
> 2 = Number of Stationary Gaps
> 4 = Number of Rotating Electrodes
> 3600 [rpm] = Disc RPM
> 0.1875 = Rotating Electrode Diameter
> 0.1875 = Stationary Electrode Diameter
> 6.5 = Rotating Path Diameter
>
> ----------------------------------------------------
> Rotary Spark Gap Outputs:
> 8 = Presentations Per Revolution
> 480 [BPS] = Breaks Per Second
> 69.6 [mph] = Rotational Speed
> 2.08 [ms] = RSG Firing Rate
> 9.335 [ms] = Time for Capacitor to Fully Charge
> 1.12 = Time Constant at Gap Conduction
> -1.78 [ms] = Electrode Mechanical Dwell Time
> 67.24 [%] = Percent Cp Charged When Gap Fires
> 13120 [peak volts] = Effective Cap Voltage
> 3.44 [joules] = Effective Cap Energy
> 437604 [peak volts] = Terminal Voltage
> 1652 [joule*seconds] = Energy Across Gap
> 109.6 [inch] = RSG Spark Length (using energy
> equation)
>
>
>


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