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Re: Newbie cap and topload questions
Original poster: jvillecheesehead@xxxxxxxxxxxxxxxx
I noticed I made a typo in my NST specs, it is 30mA, not 20. I actually
had been going off the resonant cap frequency and didn't realize the LTR
value was what is recommended and this happened to be the same as the LTR
for a 20mA transformer.
The LTR value for a 15/30 is .008uF. The capacitor I was referring to at
Electonrics Goldmine is a Phillips cap (.047uF 1600V) that looks very much
like thier 376 MMKP series that is on the good caps list but the pic isn't
clear enough to tell for sure. I will try calling to verify this. In
order to achieve the desired cap size I would need 3 strings of 18 of these
which would total .0078uF 29kv at $56.
If I were to use one of the CD caps the .1uF 942 series would require 1
string of 13 for .0077uF 26kV or the .15uF cap would require 1 string of 19
for .0079uF 38kV. Out of these configurations, do any seem to have a
better price/reliability combination then the others? If you suggest the
CD caps, where do you get these (RELL as suggested by Dave has a minimum
order or 67)?
Thanks again for all the help!
Hank
On Sun, 08 Jan 2006 6:19:47 -0500 (EST), "Tesla list" <tesla@xxxxxxxxxx> wrote:
> Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
>
> Hi,
>
> The coil looks fine. The NST can drive the coil,
> but you will probably want to upgrade the NST at
> some point in the future. A 15/60 NST would be
> ideal here (of course, that would change the cap
> size for an equivalent LTR ratio).
>
> I would probably increase the width of the toroid
> to 3" x 15". Your gap looks good and I like the
> slotted holes you added there. It can be
> difficult to produce parallel spacing between
> electrodes using a bolt on method, but I can see
> how the slotted holes would help. I personally use epoxy (quick and easy).
>
> Unsure about the caps you showed. I would
> recommend sticking with known good caps list.
> http://hot-streamer.com/TeslaCoils/MMCInfo/good-bad.txt
>
> I see your using the static gap LTR value of
> 0.005uF. Due to that, I think using the 0.1uF
> Cornell Dublier 942C20P10K would be the cheapest
> route (1 string of 20). The 0.15uF CD caps would
> require 1 string of 30 to achieve the 0.005uF value.
>
> I ran Javatc as well on your specs here except
> using the 15" toroid option while looking at your
> coil. Thought I would just share that data. Below
> Javatc data is Javammc data for the 1 string of
> 20. BTW, many of us have a very similar coils.
> Those dimensions are common and they work well.
>
> Take care,
> Bart
>
> J A V A T C v.10 - CONSOLIDATED OUTPUT
> Sunday, January 08, 2006 11:14:48 AM
>
> Units = Inches
> Ambient Temp = 68ã??
>
> ----------------------------------------------------
> Surrounding Inputs:
> 100 = Ground Plane Radius
> 100 = Wall Radius
> 100 = Wall Height
> 100 = Ceiling Radius
> 100 = Ceiling Height
>
> ----------------------------------------------------
> Secondary Coil Inputs:
> Current Profile = G.PROFILE_LOADED
> 2 = Radius 1
> 2 = Radius 2
> 20 = Height 1
> 40 = Height 2
> 800 = Turns
> 23 = Wire Awg
>
> ----------------------------------------------------
> Primary Coil Inputs:
> 3 = Radius 1
> 8.922 = Radius 2
> 20.5 = Height 1
> 20.5 = Height 2
> 11.83 = Turns
> 0.25 = Wire Diameter
> 0.005 = Primary Cap (uF)
> 0 = Desired Coupling (k)
>
> ----------------------------------------------------
> Top Load Object Inputs (dimensions & topload or ground connection):
>
> Toroid #1: minor=3, major=15, height=41, topload
> Disc #1: inside=0, outside=9, height=41, topload
>
> ----------------------------------------------------
> Secondary Outputs:
> 341.15 kHz = Secondary Resonant Frequency
> 90 degã??= Angle of Secondary
> 20 inch = Length of Winding
> 40 inch = Turns Per Unit
> 0.00243 inch = Space Between Turns (edge to edge)
> 837.8 ft = Length of Wire
> 5:1 = H/D Aspect Ratio
> 17.05 ohms = DC Resistance
> 24709 ohms = Forward Transfer Impedance
> 24297 ohms = Reactance at Resonance
> 1.29 lbs = Weight of Wire
> 11.335 mH = Les-Effective Series Inductance
> 10.964 mH = Lee-Equivalent Energy Inductance
> 11.834 mH = Ldc-Low Frequency Inductance
> 19.201 pF = Ces-Effective Shunt Capacitance
> 17.958 pF = Cee-Equivalent Energy Capacitance
> 31.122 pF = Cdc-Low Frequency Capacitance
> 4.98 mils = Skin Depth
> 14.84 pF = Topload Effective Capacitance
> 80.9 ohms = Effective AC Resistance
> 300 = Q
>
> ----------------------------------------------------
> Primary Outputs:
> 341.15 kHz = Primary Resonant Frequency
> 0 % = Percent Detuned
> 0 degã??= Angle of Primary
> 36.94 ft = Length of Wire
> 0.25 inch = Average spacing between turns (edge to edge)
> 1 inch = Primary to Secondary Clearance
> 43.529 ã?? = Ldc-Low Frequency Inductance
> 0.005 ã?? = Cap size needed with Primary L (reference)
> 99.262 ã?? = Lm-Mutual Inductance
> 0.138 k = Coupling Coefficient
> 7.25 = Number of half cycles for energy transfer at K
> 10.49 ã?? = Time for total energy transfer (ideal quench time)
>
> ----------------------------------------------------
> Transformer Inputs:
> 120 [volts] = Transformer Rated Input Voltage
> 15000 [volts] = Transformer Rated Output Voltage
> 20 [mA] = Transformer Rated Output Current
> 60 [Hz] = Mains Frequency
> 120 [volts] = Transformer Applied Voltage
> 0 [amps] = Transformer Ballast Current
> 0 [ohms] = Measured Primary Resistance
> 0 [ohms] = Measured Secondary Resistance
>
> ----------------------------------------------------
> Transformer Outputs:
> 300 [volt*amps] = Rated Transformer VA
> 750000 [ohms] = Transformer Impedence
> 15000 [rms volts] = Effective Output Voltage
> 2.5 [rms amps] = Effective Input Current
> 300 [volt*amps] = Effective Input VA
> 0.0035 [uF] = Resonant Cap Size
> 0.0053 [uF] = Static gap LTR Cap Size
> 0.0092 [uF] = SRSG LTR Cap Size
> 55 [uF] = Power Factor Cap Size
> 21210 [peak volts] = Voltage Across Cap
> 74977 [peak volts] = Recommended Cap Voltage Rating
> 1.12 [joules] = Primary Cap Energy
> 227.3 [peak amps] = Primary Instantaneous Current
> 25 [inch] = Spark Length (JF equation using
Resonance Research Corp. factors)
>
> ----------------------------------------------------
> Static Spark Gap Inputs:
> 5 = Number of Electrodes
> 1 [inch] = Electrode Diameter
> 0.28 [inch] = Total Gap Spacing
>
> ----------------------------------------------------
> Static Spark Gap Outputs:
> 0.07 [inch] = Gap Spacing Between Each Electrode
> 21210 [peak volts] = Charging Voltage
> 20390 [peak volts] = Arc Voltage
> 34333 [volts] = Voltage Gradient at Electrode
> 72822 [volts/inch] = Arc Voltage per unit
> 96.1 [%] = Percent Cp Charged When Gap Fires
> 7.923 [ms] = Time To Arc Voltage
> 126 [BPS] = Breaks Per Second
> 1.04 [joules] = Effective Cap Energy
> 340233 [peak volts] = Terminal Voltage
> 131 [power] = Energy Across Gap
> 30.2 [inch] = Static Gap Spark Length (using energy equation)
>
>
>
------------------------------------------------------------------------------
> ------------
> J A V A M M C v.1.06 - CONSOLIDATED OUTPUT
> Sunday, January 08, 2006 11:03:07 AM
>
> Capacitor Data Inputs:
> .1 [uF] = Single Capacitor value
> 2000 [volts] = Rated DC Votlage Rating
> 22 [C/watts] = Capacitor Dissipation Factor
> 10 [%] = Capacitor Rated Tollerance
> .005 [uF] = Desired Total MMC Capacitance
>
> ----------------------------------------------------
> Coil Data Inputs:
> 400 [kHz] = Coil Resonant Frequency
> 20 [caps] = Desired Capacitors per String
> 15000 [volts] = Transformer Output Voltage
> 20 [mA] = Transformer Output Current
> 120 [BPS] = Spark gap Breaks Per Secondd
> 2 [ohms] = Primary Coil Resistance
>
> ----------------------------------------------------
> JAVAMMC Outputs:
> 0.005 [uF] = Cap Bank Total Capacitance
> 0.005 [uF] = Capacitance Per String
> 1 [strings] = Number of Strings Required
> 20 [caps] = Total Number of Caps Required
> Fair = Reliability: Cap Bank Standoff Voltage
> Excellent = Reliability: Cap Temperature Rise
> 40000 [volts] = Cap Bank Rated Voltage
> 1.13 [joules] = Cap Bank Discharge Energy
> 135 [watts] = Cap Bank Nominal Power
> 21213 [volts] = Transformer Peak Voltage
> 0.0036 [TANd] = Dielectric Loss Factor
> 0.0563 [joules] = Single Cap Discharge Energy
> 0.0145 [ohms] = Single Cap Internal Resistance
> 0.0485 [watts] = Single Cap Power Dissipation
> 1.067 [Cã?? = Single Cap Temperature Rise
> 1.83 [amps] = Capacitor String RMS Current
>
>
>
> Tesla list wrote:
>
> >Original poster: jvillecheesehead@xxxxxxxxxxxxxxxx
> >Hi,
> >I'm a first time coiler and it took until now
for me to finally discover how
> >useful this list was. Anyhow, I am using a 15kv 20mA nst and have wound my
> >secondary of 4" diameter 20" height with 800 turns of 23 gauge wire. My
> >question is about a couple options with
> >caps. First, I am assuming this 35,000V
> >.005uf cap from Electronics Goldmine for $2.75 is not suitable for tesla
> coils
> >as the site claims and wanted to confirm this. Here is a link:
>
>http://www.goldmine-elec-products.com/prodinfo.asp?number=G15589&variation=&-
> aitem=72&mitem=91
> >
> > My other plan was to use this Phillips 1600V
> > .047uf cap that runs for a buck a
> >piece at the same site:
>
>http://www.goldmine-elec-products.com/prodinfo.asp?number=G14832&variation=&-
> aitem=67&mitem=91
> >
> > According to an excel calculator, I believe
> > using Terry Fritz's data, the best
> >reliability/price point would be 2 strings of 19 of these caps. Upon
> reading
> >some other posts it sounds like some people push
> >them harder without any issues
> >and was wondering if anyone had an opinion on this.
> >
> >I also had another quick question about the topload. For some reason in my
> >planning (which was a few months ago, couldn't work on the coil while I was
> at
> >college) I decided to use a toroid with 3" diameter Al ducting with a total
> >diameter of about 10 inches. Using Barton
> >Anderson's JavaTC calculator this in
> >combination with my other components results
in a 390kHz resonant frequency.
> >The size and frequency differs from many of the
> >coils I have seen online and was
> >wondering if there is any problem with using it.
> >
> >Lastly, I thought I would share a picture of my
> >spark gap that includes a simple
> >modification to the Richard Quick design that allows for increased
> >adjustability. Thanks for the help!
> >
> >
> >
> >
> >