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Re: Newbie cap and topload questions
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 = 68°F
----------------------------------------------------
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 deg° = 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 deg° = 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 µH = Ldc-Low Frequency Inductance
0.005 µF = Cap size needed with Primary L (reference)
99.262 µH = Lm-Mutual Inductance
0.138 k = Coupling Coefficient
7.25 = Number of half cycles for energy transfer at K
10.49 µs = 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 [C°] = 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!