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Re: Beginner Q's



Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>



With only a 30 mA drive xmfr and a 3.5 inch coil don't use 24 AWG. You need more turns --- around 1,200 to 1,400 on the sec coil with an aspect (winding) ratio of 4.5:1. Using only 600 turns will drastically cut your output performance down. A 4 inch dia. ID PVC water pipe sanded down inside and out, coated inside and out, then wound will work good with this size xmfr. We use 30 AWG on our secondaries with this size xmfr. You could get away with 28 AWG but don't want to go smaller or output is reduced.

Use a .008 uF (8 nF) tank capacitor value --- easy to make up with MMCs and a lot better than rolling your own from a space savings standpoint. This will keep your xmfr from trying to resonate with the cap. Also, be sure to use a Terry filter on the xmfr.

Using MMC caps also allows you to keep your coil base small which makes the spark look larger. A very large base with a small spark has an illusion of making the spark look even smaller.

Dr. Resonance


Ok I think I need some education! If you will permit me I would like to post the calcs for the coil I am trying to build. I understand some of what it means but I am an electrician not an engineer. Any pointers or information on this design would greatly help!!

'Flea

POWER SUPPLY

Allanson Luminous Tube Transformer                            120v input

                    15kv
output

                    30ma

                    450VA

General Electric Volt-Pac Variable Transformer               120v input

                    120
- 140v output

                    7.5A

SECONDARY COIL

Outer
Diameter
3.5 inches
Coil
Length
14 inches
Aspect
Ratio
1:4
Turns
651.1628N
Windings
#24 Gauge Magnet Wire
Wire
Length
596.3566 feet
Resonant
Frequency                                                           680.287 KHz
RF
Resistance
249.68 12 Ohms
XL @
Resonance
35618.78 Ohms
Max Unloaded Q @ Resonance                                        142.657
Inductance
8.337334mH
Distributed / Stray
Capacitance                                         6.572969pF
Approximate Loaded
Q                                                       50.94893
Terminal
Capacity
6.572969pF
Resonant Frequency Drop
to                                            480.963 KHz


TRANSFORMER / CAPACITOR MATCHING

Max Primary
Capacitance                                                   .0038 microfarads
Minimum Voltage
Rating                                                    37500 Volts


SPARK GAP

Type
Static
Number of
Gaps                                                                   8
Gap
Spacing
.010 - .020 inches

TANK CAPACITOR

Type
Rolled
Plate
Thickness
Aluminum Roof Flashing
Dielectric
;                  .040 Inches (40 mils)  Polypropylene
Plate
Length
60 Inches
Plate
Width
14 Inches
Capacitance per
Roll
.019 microfarads
Voltage per
Roll 8000v
Rolls Required (Series Connected)                                   5
Final
Capacitance
.0038 microfarads
Maximum Transformer
Capacitance                                  .0038 microfarads
Final Volt age
Value                                                              40kV


PRIMARY COIL < B style="mso-bidi-font-weight: normal"> Inductance Needed for Resonance 14.4microhenries Type Flat Spiral Conductor .24" (1/4") copper tube - .3725" (5/16") OD Number of Turns 8N Spiral OD 14.75" (14-3/4") Spiral ID 5.375" (5-3/8") Turns Spacing .3125" (5/16") Approximate Tap Point Turn 7-8


TOPLOAD (TOROID)

TOROID 1

Torus
Size
1" X 6"
Torus
Capacitance
5.10 pF - This to match secondary terminal capacity
Suggested
Diameter                                                            2" - 4"
Suggested Power
Level                                                      200W - 400W

TOROID 2

Torus
Size
2" X 8"
Torus
Capacitance
6.80 pF - This to match secondary terminal capacity
Suggested
Diameter                                                            3" - 5"
Suggested Power
Level                                                      400W - 800W