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-----------------------------------------
----------- Secondary Outputs: -----------------------------------------
----------- 488.87 kHz = Secondary Resonant Frequency 90 deg° = Angle of Secondary 18 inch = Length of Winding 55.6 inch = Turns Per Unit 0.0001 inch = Space Between Turns (edge to edge) 785.4 ft = Length of Wire 6:1 = H/D Aspect Ratio 25.2138 Ohms = DC Resistance 31097 Ohms = Reactance at Resonance 0.76 lbs = Weight of Wire 10.124 mH = Les-Effective Series Inductance 11.604 mH = Lee-Equivalent Energy Inductance 11.74 mH = Ldc-Low Frequency Inductance 10.469 pF = Ces-Effective Shunt Capacitance 9.134 pF = Cee-Equivalent Energy Capacitance 18.906 pF = Cdc-Low Frequency Capacitance 3.96 mils = Skin Depth 4.217 pF = Topload Effective Capacitance 117.6968 Ohms = Effective AC Resistance 264 = Q
-----------------------------------------------
----- Primary Outputs: -----------------------------------------
----------- 488.86 kHz = Primary Resonant Frequency 0 % = Percent Detuned 0 deg° = Angle of Primary 12.82 ft = Length of Wire 2.13 mOhms = DC Resistance 0.778 inch = Average spacing between turns (edge to edge) 1.366 inch = Proximity between coils 1.42 inch = Recommended minimum proximity between coils 6.232 µH = Ldc-Low Frequency Inductance 0.015 µF = Cap size needed with Primary L (reference) 0.861 µH = Lead Length Inductance 27.161 µH = Lm-Mutual Inductance 0.1 k = Coupling Coefficient 0.126 k = Recommended Coupling Coefficient 10 = Number of half cycles for energy transfer at K 10.16 µs = Time for total energy transfer (ideal quench time)
-------------------------------------------
--------- Transformer Inputs: ------------------------------------------
---------- 120 [volts] = Transformer Rated Input Voltage 7500 [volts] = Transformer Rated Output Voltage 30 [mA] = Transformer Rated Output Current 60 [Hz] = Mains Frequency 120 [volts] = Transformer Applied Voltage 0 [amps] = Transformer Ballast Current 0.35 [ohms] = Measured Primary Resistance 4520 [ohms] = Measured Secondary Resistance
--------------------------------------
-------------- Transformer Outputs: -----------------------------------------
----------- 225 [volt*amps] = Rated Transformer VA 249931 [ohms] = Transformer Impedence 7500 [rms volts] = Effective Output Voltage 1.88 [rms amps] = Effective Transformer Primary Current 0.03 [rms amps] = Effective Transformer Secondary Current 225 [volt*amps] = Effective Input VA 0.0106 [uF] = Resonant Cap Size 0.0159 [uF] = Static gap LTR Cap Size 0.0277 [uF] = SRSG LTR Cap Size 41 [uF] = Power Factor Cap Size 10607 [peak volts] = Voltage Across Cap 26517 [peak volts] = Recommended Cap Voltage Rating 0.84 [joules] = Primary Cap Energy 521.5 [peak amps] = Primary Instantaneous Current 21.7 [inch] = Spark Length (JF equation using Resonance Research Corp. factors) 13.7 [peak amps] = Sec Base Current
-----------------------------------------
----------- Static Spark Gap Inputs: ------------------------------------------
---------- 7 = Number of Electrodes 0.216 [inch] = Electrode Diameter 0.2 [inch] = Total Gap Spacing
-----------------------------------------
----------- Static Spark Gap Outputs: -----------------------------------------
----------- 0.033 [inch] = Gap Spacing Between Each Electrode 10607 [peak volts] = Charging Voltage 10599 [peak volts] = Arc Voltage 35825 [volts] = Voltage Gradient at Electrode 52993 [volts/inch] = Arc Voltage per unit 99.9 [%] = Percent Cp Charged When Gap Fires 9.403 [ms] = Time To Arc Voltage 106 [BPS] = Breaks Per Second 0.84 [joules] = Effective Cap Energy 428801 [peak volts] = Terminal Voltage 90 [power] = Energy Across Gap 23 [inch] = Static Gap Spark Length (using energy equation)
Obviously, the spark gap numbers are purely random, but the rest of it is material on hand (used the sphere, because I knew the measurements.) Does anything need improved/modified? The Primary coils measurements would need work, I assume, because I have little faith in my ability to measure out to the 1/1000 of an inch.
Registered Member #480
Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644
Diarrq -
Great start!
Your primary coil doesn't need to be fabricated to .001" precision; JAVATC just happens to provide output data to three decimal places, when a tolerance of 1/10" would be perfectly adequate.
I know that you already have a 4" sphere available as a topload, but I'd recommend that you design the primary with enough extra turns to accommodate an aluminum duct toroid of, say, 3" X 10" or so. The problem is that your 4" sphere is rather small, and probably won't provide enough electrostatic shielding of the top turns of the secondary to prevent excessive corona from the top turns.
Your JAVATC file shows a suggested primary inner diameter of 6", an outer diameter of about 15.5", and a total of 4.6 turns at the tap point. Build your primary supports to locate the .25" tubing conductor on 1/2" centers, which will provide a 1/4" space between turns. You will always want to add around 2 extra turns to give some additional range of adjustment for tuning, but also go back and re-run the analysis, substituting a 3" X 10" toroid for the sphere, and see how many primary turns would be required. If you build your primary with enough turns to "tune" with a 3" X 10" toroid, you can start with your sphere, and add a toroid later.
Registered Member #1904
Joined: Sat Jan 03 2009, 02:40AM
Location: Pittsburgh
Posts: 14
Does the gauge of the wire affect the coil in any way other than resistance? I can do 1000 turns of #25 or 890 odd turns of #24. Which would operate better?
Registered Member #480
Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644
Diarrq -
Actually, you'd be better off using smaller gage wire (like #28 or #30). Your target turns count should be somewhere around 1200. Anything from 800-2000 turns will "work", but for this sized coil around 1200 turns seems to yield very good performance. #28 AWG is still large enough to wind easily, #30 is a little more difficult but still fairly easy to handle.
You asked "Does the gauge of the wire affect the coil in any way other than resistance?".
Yes, in several ways. Assuming you keep the overall winding length the same, smaller gage wire will increase the turns count, which will increase inductance. Increasing secondary inductance will decrease the secondary's resonant frequency. Decreasing the secondary's resonant frequency will require that you also decrease the resonant frequency of the primary circuit. If you achieve this by adding more turns to the primary, you will increase the primary inductance, which can reduce the amount of power "burned up" in the spark gap and improve coil performance.
So, everything is interactive ....... generally, a secondary turns count of around 1200 is a good place to start.
Registered Member #1127
Joined: Mon Nov 19 2007, 12:08AM
Location:
Posts: 139
Herr Zapp wrote ...
Diarrq -
Actually, you'd be better off using smaller gage wire (like #28 or #30). Your target turns count should be somewhere around 1200. Anything from 800-2000 turns will "work", but for this sized coil around 1200 turns seems to yield very good performance. #28 AWG is still large enough to wind easily, #30 is a little more difficult but still fairly easy to handle.
You asked "Does the gauge of the wire affect the coil in any way other than resistance?".
Yes, in several ways. Assuming you keep the overall winding length the same, smaller gage wire will increase the turns count, which will increase inductance. Increasing secondary inductance will decrease the secondary's resonant frequency. Decreasing the secondary's resonant frequency will require that you also decrease the resonant frequency of the primary circuit. If you achieve this by adding more turns to the primary, you will increase the primary inductance, which can reduce the amount of power "burned up" in the spark gap and improve coil performance.
So, everything is interactive ....... generally, a secondary turns count of around 1200 is a good place to start.
Regards, Herr Zapp
Same thing is also true about high inductance on the secondary as well. I notice that as I approach 85 mH - with a low inductance primary (say 12 uH or so) I achieve nearly 98% of Freau's spark length formula. When I exaggerated the coil form even more - adding 110 mH worth of inductance on the secondary - keeping the same low inductance on the primary circuit I achieved 103% of Freau's spark length at 2.3 kVA - my record was 82" - it should have been 79". My capacitance was LTR however.
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New at this, advice would be greatly appreciated