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weak sparks from a breakout point, help needed

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LAN_403

Gordie Orange

Wed Apr 13 2016, 09:04PM

Registered Member #55076 Joined: Sat May 23 2015, 08:26AM
Location:
Posts: 20

First run of my rebuilt coil tonight and sadly disappointed, very weak streamers from a breakout point.

components are as follows
6 inch secondary thats roughly 27inch of winding,
6x24 inch toroid
10kv 50ma NST
44.3nF cap bank (20kv)
synchronous rotary gap 200bps

I am out of my depth here and learning while I go thanks to forums like this and youtube

Earth p[points are fine so would retarding or advancing the gap help and what would a decent gap size be? it spark gap starts firing when I turn it up to about 180v

GrantX

Thu Apr 14 2016, 07:34AM

Registered Member #4074 Joined: Mon Aug 29 2011, 06:58AM
Location: Australia
Posts: 335

What's the resonant frequency of the primary and secondary circuits? JavaTC or similar can be used to calculate the resonant frequencies (and much more, like coupling) quickly.

Apart from tuning, have you noticed any odd behaviour? For example, is there noticeable heat in the capacitors? Can you see any inter-turn sparking on the secondary? Is there any metal inside the secondary coil former (which can lead to "hidden" discharges inside your coil, causing carbon tracking and low performance)?

Gordie Orange

Thu Apr 14 2016, 09:19AM

Registered Member #55076 Joined: Sat May 23 2015, 08:26AM
Location:
Posts: 20

I'll have a look at javaTC when kids are napping
No heat in caps, no sparking on secondary no metal inside former (made that mistake on my first 4 inch coil)
I used teslamap to work out cap bank size

Gordie Orange

Thu Apr 14 2016, 01:43PM

Registered Member #55076 Joined: Sat May 23 2015, 08:26AM
Location:
Posts: 20

GrantX wrote ...

What's the resonant frequency of the primary and secondary circuits? JavaTC or similar can be used to calculate the resonant frequencies (and much more, like coupling) quickly.

Apart from tuning, have you noticed any odd behaviour? For example, is there noticeable heat in the capacitors? Can you see any inter-turn sparking on the secondary? Is there any metal inside the secondary coil former (which can lead to "hidden" discharges inside your coil, causing carbon tracking and low performance)?

Assuming I've input everything right into JavaTC this is what I get

J A V A T C version 13.2 - CONSOLIDATED OUTPUT
14/04/2016, 14:41:50

Units = Inches
Ambient Temp = 68Â°F

------------------------------------------- ---------
Surrounding Inputs:
------------------------------------------ ----------
100 = Ground Plane Radius
100 = Wall Radius
150 = Ceiling Height

------------------------------------------ ----------
Secondary Coil Inputs:
------------------------------------------ ----------
Current Profile = G.PROFILE_LOADED
2.26925 = Radius 1
2.26925 = Radius 2
2 = Height 1
28 = Height 2
797 = Turns
20 = Wire Awg

--------------------------------------------- -------
Primary Coil Inputs:
------------------------------------------ ----------
Round Primary Conductor
4 = Radius 1
7.224 = Radius 2
2 = Height 1
2 = Height 2
4.4327 = Turns
0.31 = Wire Diameter
1 = Ribbon Width
0.1 = Ribbon Thickness
0.0443 = Primary Cap (uF)
30 = Total Lead Length
0.2 = Lead Diameter

---------------------------------------- ------------
Top Load Inputs:
------------------------------------------ ----------
Toroid #1: minor=6, major=24, height=33, topload

----------------------------------------- -----------
Secondary Outputs:
----------------------------------------- -----------
259.72 kHz = Secondary Resonant Frequency
90 degÃ¯Â¿Â½ = Angle of Secondary
26 inch = Length of Winding
30.7 inch = Turns Per Unit
0.00066 inch = Space Between Turns (edge to edge)
947 ft = Length of Wire
5.73:1 = H/D Aspect Ratio
9.5357 Ohms = DC Resistance
18731 Ohms = Reactance at Resonance
2.93 lbs = Weight of Wire
11.478 mH = Les-Effective Series Inductance
12.014 mH = Lee-Equivalent Energy Inductance
11.743 mH = Ldc-Low Frequency Inductance
32.715 pF = Ces-Effective Shunt Capacitance
31.257 pF = Cee-Equivalent Energy Capacitance
46.205 pF = Cdc-Low Frequency Capacitance
5.48 mils = Skin Depth
26.99 pF = Topload Effective Capacitance
57.7224 Ohms = Effective AC Resistance
325 = Q

----------------------------------------------- -----
Primary Outputs:
----------------------------------------- -----------
260.97 kHz = Primary Resonant Frequency
0.48 % low = Percent Detuned
0 degÃ¯Â¿Â½ = Angle of Primary
13.02 ft = Length of Wire
1.41 mOhms = DC Resistance
0.417 inch = Average spacing between turns (edge to edge)
1.56 inch = Proximity between coils
1.01 inch = Recommended minimum proximity between coils
7.535 Ã¯Â¿Â½H = Ldc-Low Frequency Inductance
0.04473 Ã¯Â¿Â½F = Cap size needed with Primary L (reference)
0.861 Ã¯Â¿Â½H = Lead Length Inductance
34.283 Ã¯Â¿Â½H = Lm-Mutual Inductance
0.115 k = Coupling Coefficient
0.131 k = Recommended Coupling Coefficient
8.7 = Number of half cycles for energy transfer at K
16.52 Ã¯Â¿Â½s = Time for total energy transfer (ideal quench time)

------------------------------------------- ---------
Transformer Inputs:
------------------------------------------ ----------
240 [volts] = Transformer Rated Input Voltage
10000 [volts] = Transformer Rated Output Voltage
50 [mA] = Transformer Rated Output Current
50 [Hz] = Mains Frequency
240 [volts] = Transformer Applied Voltage
0 [amps] = Transformer Ballast Current

----------------------------------------- -----------
Transformer Outputs:
----------------------------------------- -----------
500 [volt*amps] = Rated Transformer VA
200000 [ohms] = Transformer Impedence
10000 [rms volts] = Effective Output Voltage
2.08 [rms amps] = Effective Transformer Primary Current
0.05 [rms amps] = Effective Transformer Secondary Current
500 [volt*amps] = Effective Input VA
0.0159 [uF] = Resonant Cap Size
0.0239 [uF] = Static gap LTR Cap Size
0.0415 [uF] = SRSG LTR Cap Size
28 [uF] = Power Factor Cap Size
14142 [peak volts] = Voltage Across Cap
35355 [peak volts] = Recommended Cap Voltage Rating
4.43 [joules] = Primary Cap Energy
1084.4 [peak amps] = Primary Instantaneous Current
32.3 [inch] = Spark Length (JF equation using Resonance Research Corp. factors)
29.5 [peak amps] = Sec Base Current

----------------------------------------- -----------
Rotary Spark Gap Inputs:
------------------------------------------ ----------
1 = Number of Stationary Gaps
4 = Number of Rotating Electrodes
3000 [rpm] = Disc RPM
0.375 = Rotating Electrode Diameter
0.375 = Stationary Electrode Diameter
10.6 = Rotating Path Diameter

---------------------------------------- ------------
Rotary Spark Gap Outputs:
----------------------------------------- -----------
4 = Presentations Per Revolution
200 [BPS] = Breaks Per Second
94.6 [mph] = Rotational Speed
5 [ms] = RSG Firing Rate
44.3 [ms] = Time for Capacitor to Fully Charge
0.56 = Time Constant at Gap Conduction
450.44 [Âµs] = Electrode Mechanical Dwell Time
43.13 [%] = Percent Cp Charged When Gap Fires
6099 [peak volts] = Effective Cap Voltage
0.82 [joules] = Effective Cap Energy
229604 [peak volts] = Terminal Voltage
165 [power] = Energy Across Gap
33.2 [inch] = RSG Spark Length (using energy equation)

--------------------------------------- -------------
Static Spark Gap Inputs:
------------------------------------------ ----------
6 = Number of Electrodes
1.25 [inch] = Electrode Diameter
0.25 [inch] = Total Gap Spacing

----------------------------------------- -----------
Static Spark Gap Outputs:
----------------------------------------- -----------
0.05 [inch] = Gap Spacing Between Each Electrode
14142 [peak volts] = Charging Voltage
19414 [peak volts] = Arc Voltage
34822 [volts] = Voltage Gradient at Electrode
77654 [volts/inch] = Arc Voltage per unit
137.3 [%] = Percent Cp Charged When Gap Fires
427.227 [ms] = Time To Arc Voltage
2 [BPS] = Breaks Per Second
8.35 [joules] = Effective Cap Energy
730857 [peak volts] = Terminal Voltage
20 [power] = Energy Across Gap
26.1 [inch] = Static Gap Spark Length (using energy equation)

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