602 lines
25 KiB
Plaintext
602 lines
25 KiB
Plaintext
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=======================================================================
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INFORMATION FOR BUILDING CAPACITORS: Comments
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Puncture Voltage |
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Material Dielectric strength per Mil |
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"K" (0.001 inch) |
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-----------------------------------------------------------------------
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Miscellaneous
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-------------
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Vacuum 1.0
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Paper, bond 3.0 200
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Paper, Royal Grey 3.0 200
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Paper, telephone, treated 2.5 - 4 200 - 250 *
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Paper, Parafin Coated 2 -3.5
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Paper, Kraft 2.2
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Oil, Castor 4.67
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Oil, Mineral, Squibb 2.7 200
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Oil, Mineral 2.2
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Oil, Transformer 2.1 - 2.5 75 *
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Rubber 3.0
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Rubber, Hard 3.0 160 - 500 *
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Rubber, Vulcanized 3.2 - 3.9 1
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Fibre 5.0 - 7.5 150 - 180
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Fibre, Red 5.0
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Mica 4.5 - 8.0 3800 - 5600
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Mica, Ruby 5.4 3800 - 5600
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Quartz 3.8 - 5.0 1000
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Quartz (Fused) 4.2 150 - 200 *
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Shellac 2.5 - 4.0 200 - 400
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Spar Varnish 4.8 - 5.5
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Steatite, low loss 5.8 150 - 315
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Steatites (Magnesium silicate,etc) 5.5 - 7.5 200 - 300
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Cambric (Varnished) 4.0 2
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Alsimag 196 5.7
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Gutta Percha 4.0 3
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Amber 3.0 - 7.0 4
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Resin 2.48 - 2.57
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Enamel 5.1 450
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Mycalex 7.4 250
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Silicone RTV 3.6 550
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Wood 2.0 - 5.2
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Wax (Parafin) 2.1 - 2.5 250 - 450 *
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Beeswax 2.9 - 3.0
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Slate 7.0 5
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Barium titanate(25 C) 1200
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Bariam titanate 6000
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Titanium dioxide 125
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Cellulose acetate 3.3 - 3.9 250 - 600
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Casein, Moulded 6.4 6
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Polytetraflourethylene 2.0 A
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Aluminum oxide 8.7
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Tantalum pentoxide 22
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Glass
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-----
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Glass 4.8 - 10 300
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Plate Glass 6.8 - 8.4
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Pyrex Glass 4.8 - 10 335
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Window Glass 7.6 - 7.8 200 - 250
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Ceramics
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--------
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Cordierite ceramics 5.0 - 5.5 100
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Magnesium titanate ceramic 12 - 18 150
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Porcelain 5.1 - 7.5 40 - 280
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Titanium dioxide ceramic 70 - 90 100
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Titanium-zirconium dioxide ceramic 40 - 60 150
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Plastics
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--------
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Bakelite 4.4 - 5.8 300
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Bakelite, Mica filled 4.7 325 - 375
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Epoxy Circuit Board 5.2 700
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Formica 4.6 - 4.9 450 7
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Nylon (lowest values of 3 types) 3.2 407
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PVC (rigid type) 2.95 725
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Plexiglass 2.8 450 - 990
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Polyethylene 2.2 - 2.3 450 - 1200
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Polycarbonate (Lexan) 2.96 400
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Polyethylene Terphthalate (Mylar) 3.0 - 3.1 7500
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Polystyrene 2.5 - 2.6 500 - 700
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Teflon 2.1 1000 - 2000
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Gases
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--------
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Air (dry air at 1 atm) 1.0006 30 - 70
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Air (20 atm, 19 deg. C) 1.0108 500 *
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Carbon dioxide ( 1 atm, 0 deg. C) 1.000985 36 *
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Carbon dioxide (20 atm, 15 deg. C) 1.020
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Hydrogen (1 atm,0 deg.C) 1.000264 26.1 *
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Liquids
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--------
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Amonia (liquid) 22
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Benzene 2.28
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Carbon tetrachloride 2.24 8
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Chlorinated diphenyl 6.5 9
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Ethyl Alcohol (O C) 28.4
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Ethyl alchohol (20 deg.C) 25.8
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Methyl alchohol 33.1
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Water (distilled) 80 - 81
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LEGEND:
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* = Measured in Kilovolts per centimeter. All others are Volts per
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mil (.001 inch) unless otherwise stated.
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1 = Vulcanized means it has been melted, or heated in some way.
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2 = Cambric is a finely woven white linen or cotton fabric.
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3 = Gutta Percha is a rubbery substance made from the latex of tropical
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trees and is used in insulation, waterproofing, and dentist use it
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in thin sheets sometimes when working on teeth.
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4 = Amber is a hard, translucent, yellow, orange, or brownish yellow
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fossil resin, used in making ornamental objects like jewelry.
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5 = Slate is a fine grained metamorphic rock that splits into thin
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smooth faced layers. Black Boards for writting are made of this.
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Also used as roofing material in some areas.
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6 = Casein is a white, tasteless, oderless milk and cheese protein used
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in the manufacture of plastics, glues, paints, and food. The word
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'moulded' means it has been shaped by a mold.
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7 = Formica is a trademark for any of various high-pressure laminated
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plastic sheets of melamine and phenolic materials used for chemical
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and heat-resistant surfaces.
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8 = Carbon tetrachloride is a very toxic substance. It has also been
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shown to cause cancer in lab animals. It is banned in most labs. It
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is a liquid that was used as a strong solvent.
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9 = Chlorinated diphenyl is a liquid dielectric that is used to
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impregnate Kraft paper in small A.C. capacitors. This is a PCB
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and may cause cancer, handle carefully.
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A = Polytetraflourethylene films retain good properties even at
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200 degrees Celsius (200 C).
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atm = atmospheres (pressure of air at sea level is 1 atm).
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deg.C = degrees Celsius.
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Warning - Some liquids and gases listed may be explosive
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under the right conditions. Many solids can
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catch fire and burn. Use CAUTION and GOOD COMMON SENSE.
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Note: Some books gave very different values for each substance so I
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have given you the highest and lowest values reported. The values
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will depend on the purity of the substance your using. If you
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know your substance is very pure then use the higher value
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reported. If you know your substance is contaminated or of poor
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quality then use the lower values reported. If you have unknown
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purity then use the average of the values given.
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=======================================================================
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EXPLAINATION OF EQUATIONS:
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Here are some real handy equations. They are very simple and easy to
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use.
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x = Multiply by
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/ = divide by ( may also use line seperating terms above and below
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line as in standard mathematics).
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( ) = Terms in parentheses should be calculated first as in standard
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algebraic equations.
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pi = 3.141592654. The circumferance of a circle divided by it's
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diameter will always give you this constant.
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2
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Z = means the term "Z" multiplied by itself one time,"Z x Z".
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Note: In some cases I do not use the symbol "x" but instead simply
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put the terms close together, example: "LC" instead of "L x C".
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This is standard for algebraic equations and means "multiply by".
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=======================================================================
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MATH FOR TESLA COILS
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1. Determine your neon sign transformer (or other transformer's)
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Impedence:
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E
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Z = ---
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I
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Z = Impedence
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E = volts
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I = current in Amps
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Note: divide milliamps by 1000 to get Amps. 30 milliamps = .030 Amps.
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The Impedence of the primary capacitor should match the Impedence of the
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transformer at 60 Hz (60 Hz is the AC cycle rate of common household
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wall sockets, at least in America).
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2. To match Impedence and determine capacitor value:
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1
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C = -------------------
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2 x pi x Z x .00006
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C = capacitance in microfarads needed for primary capacitor.
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Z = Impedence from equation one (Transformer Impedence)
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pi = 3.141592654
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Note: The .00006 is the 60 Hz AC, if you live outside the US then
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substitute your cycle rate.
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Next you need to find the Reactance of the primary capacitor at the
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frequency you have choosen. Many times the frequency is decided by the
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length of wire used on the secondary coil. See below for equations that
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determine frequency by length of wire used on secondary.
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When we find the Reactance , we can then find your needed Inductance
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for the Primary coil.
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3. To determine Reactance of capacitor:
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1
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X(C) = ---------------
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2 x pi x C x F
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X(C) = capacitor Reactance
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C = Capacitor value in microfarads, from equation 2)
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F = Frequency in Mhz (megahertz)
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pi = 3.141592654
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Note: To convert kilohertz to megahertz simply divide by 1000.
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190 Khz = .190 Mhz
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4. To determine the Inductance needed for Primary coil:
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Set X(L) = X(C)
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X(L)
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L = ------------
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2 x pi x F
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L = Inductance in microhenries needed for Primary Coil.
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To get millihenries divide the answer by 1000.
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X(L) = Reactance from equation 3, same as X(C).
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F = frequency in Megahertz. Divide Khz by 1000 to get Mhz.
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pi = 3.141592654
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Now you know the values for your capacitor and primary coil. These
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values will give you the best ringing for your circuit (ie. more bang
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for your buck)! Use the equations below to finnish the project.
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Note: Many people don't go to the trouble to work these equations out.
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They simply slap the parts together and then try to tune. If you work
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the equations out first you will save lots of time in tuning, you will
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at least be in the right ball park! Also, just because you worked it
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out on paper that doesn't mean it will work the first time you plug it
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in. Trial and error is a large part of the Tesla Coil hobby!
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=======================================================================
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CAPACITORS IN PARALLEL:
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|__C1__|
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|__C2__|
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|__C3__|
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Capacitance = C1 + C2 + C3, etc...
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Maximum voltage rating will be equal to the voltage rating of the
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lowest voltage capacitor of the group.
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=======================================================================
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CAPACITORS IN SERIES:
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|__C1__C2__C3__|
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1 1 1
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Capacitance = 1 / --- + --- + ---, etc...
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C1 C2 C3
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The total capacitance of several capacitors in series will always be
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LESS than that of the smallest capacitor.
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Total voltage rating increases with number of capacitors in series.
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Simply add the voltage ratings together.
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When capacitors are placed in series to increase voltage rating they
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should have the same capacitance and voltage rating else voltages will
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divide unevenly, most likely causing failure.
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=======================================================================
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EQUATION 1: PLATE TYPE CAPACITORS
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Capacitance (in microfarads) = (0.224 KA / d) (N-1)
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0.224 x Dielectric Strength x Area of plate
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C = ----------------------------------------- x (Number of plates - 1)
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distance between plates in inches
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=======================================================================
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EQUATION 2: LEYDEN JAR or SALT WATER TYPE CAPACITORS (jar/bottle type)
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2
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C = .0884 k ( pi r + 2 pi r l )
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------------------------------
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1,000,000 t
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C = Capacitance in microfarads
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k = dielectric strength
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r = jar radius in centimeters
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l = height of the jar portion used (in centimeters)
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t = thickness of the jar wall in centimeters
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pi = 3.141592654
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2
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r = r x r (radius squared)
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=======================================================================
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EQUATION 3: FREQUENCY OF A CIRCUIT
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1
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f = --------------------
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__________
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2 pi / L C
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f = frequency in cycles per second
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L = circuit inductance in henries
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C = circuit capacitance in farads
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pi = 3.141592654
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_________
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The symbol " / " means the square root
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For a result "f" in Khz: enter "C" in microfarads, "L" in microhenries
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and multiply result by 1000.
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=======================================================================
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EQUATION 4: INDUCTANCE OF A FLAT PANCAKE COIL
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Picture a 1 inch flat ribbon that is about 30 feet long. Now, roll
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that ribbon into a spiral that has all its sides about 1/2 inch apart.
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Most common material is Aluminum Roof Flashing. Use plastic bolts to
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hold sections of strips together if you have short pieces of ribbon.
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This makes a good mechanical connection (you can't solder aluminum).
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center axis
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| | | | | | | | | | | <---cross section
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| of flat spiral
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|---A----| |---W---| coil.
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2 2
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a x n
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L = ---------------
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8 a + 11w
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L = inductance in microhenries.
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a = average radius in inches as measured from the central axis to
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the middle of the winding.
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n = number of turns in the winding.
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w = width of the coil in inches.
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Note: Make sure you measure "a" from center axis - the very middle
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of your secondary sitting inside of your primary.
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=======================================================================
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EQUATION 5: NUMBER OF TURNS FOR A HELICAL PRIMARY
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_________________________
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/
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N = / L [( 9 x R) + (10 x H)]
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/ --------------------------
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/ 2
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\/ R
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N = Number of turns needed.
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L = inductance in microhenries desired.
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R = radius (inches).
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H = height (inches).
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_________
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The symbol " / " means the square root, in this case of whole
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equation.
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=======================================================================
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EQUATION 5: LENGTH OF WIRE NEEDED FOR DESIRED FREQUENCY OF COIL
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300,000
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L = ------- / 4 x (3 / .9144)
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f
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f = frequency, in Khz, that is desired for coil.
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L = length of wire needed, in feet, for desired frequency.
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/ = divided by.
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Note - 300,000 is the speed of light in Kilometers per second. the
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term "3/.9144" is a conversion factor to turn meters to feet.
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You don't have to understand this. Just thought I would tell
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those who were wondering.
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=======================================================================
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EQUATION 6: FRQUENCY OF COIL
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300,000
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f = ------------------------------
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T x W x pi x (.9144 / 36) x 4
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f = frequency of coil in Khz
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T = number of turns on coil
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W = width of the coil in inches
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pi = 3.141592654
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=======================================================================
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EQUATION 7: CAPACITANCE OF A SPHERE IN SPACE
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R
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C = -------
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9
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9 x 10
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C = capacitance in Farads
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R = radius in meters
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9
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9x10 = 9,000,000,000
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6
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Note: To convert Farads to microfarads simply multiply by 10 or in
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other words by 1,000,000.
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=======================================================================
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EQUATION 8: CAPACITANCE OF A SPHERE SUSPENDED IN A DIELECTRIC
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K x R
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C = ---------
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9
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9 x 10
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C = capacitance in Farads
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R = radius in meters
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K = dielectric constant
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6
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Note: To convert Farads to microfarads simply multiply by 10 or in
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other words by 1,000,000.
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=======================================================================
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EQUATION 9: CAPACITANCE OF A TOROID
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___________________
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/ 2
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C =(1+ (0.2781 - d2/d1)) x 2.8 x / 2 pi (d1-d2)(d2/2)
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/ -------------------
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\/ 4 pi
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C = capacitance in picofarads (+- 5% )
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d1 = outside diameter of toroid in inches
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d2 = diameter of cross section (cord) of toroid in inches
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Equation courtesy of Bert Pool
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=======================================================================
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EQUATION 10: POWER FACTOR CORRECTION FOR NEON SIGN TRANSFORMERS
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Neons typically have an efficiency of about 50%, in that they
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draw twice as much power as they put out. This problem can be
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resolved with the use of power factor correction (pfc) capaci-
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tance across the line. The pfc capacitors used are the same as
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for capacitor starting motors. The voltage rating should be at
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least twice the line current used, and I like a 4x voltage margin
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for long life. The formula used to determine ballpark pfc is as
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follows:
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9
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10^
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C = Corrected kVA ------ 2
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2(pi)fe^
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This should read C = Corrected kVA times (10 to the ninth power)
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over, (2 pi times f times e squared)
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C = required capacitance in microfarads
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f = frequency of applied voltage
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e = applied voltage
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CORRECTED KVA is determined by dividing the volt*amps (watts)
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output of the neon sign xfrmr by 1000
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Equation courtesy of Richard Quick
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=====================================================================
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TESLA COIL SCHEMATIC --------
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| | TC
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--------
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O
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O
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SG SC FCC PC SG P-COIL O S-COIL
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O---------------OOOOO---------> <----- O O
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NST O | | | | O O
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O | | | | O O
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-----O||O * --- --- |--->O O
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O||O O O
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-----O||O * --- --- O O
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110 | O | | | O O
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Volts | O | | | O O
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| O---------------OOOOO---------------------| |
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Gnd Gnd
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NST = Neon Sign Transformer, 110 volts primary, 15,000 volt secondary
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at 30-60 miliamps.
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SG = Safty Gap. A spark gap to insure your transformer doesn't get fried.
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SC = Safty Capacitor. 300-500 picofarad rated at 50 KV.
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FCC = Ferrite Core Choke. This prevents real high voltages from coming
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back towards your transformer. It also seperates the capacitors.
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PC = Primary Capacitor. Normally .01-.02 microfarads rated 50 KV.
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SG = Spark Gap.
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P-COIL = Primary Coil.
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S-Coil = Secondary Coil.
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TC = Terminal Capacitor. The big ball or coffee can on top.
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Gnd = Ground.
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Note: This is one of several possible schematics. It's just the one I
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happen to use.
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=======================================================================
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Bibliography:
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Books:
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-------
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Theory and Applications of Electricity and Magnetism, Charles A.
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Culver, 1947, McGraw Hill Book Company, Inc.
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Concept In Physics, Third edition, Frankln Miller Jr., Thomas J.
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Dillon, Malcom K. Smith, 1980, Harcourt Brace Jovanovich, Inc.
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Tesla Coil Secrets, R.A. Ford, 1985, Lindsay Publications Inc.
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Tesla Coil, George Trinkaus, 1989, High voltage Press @Lindsay
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Publications.
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High frequency Apparatus, Thomas Stanley Curtis, 1916, Lindsay
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Publications.
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Allied Electronics Data Handbook, 1970
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Tesla Coil Design Manual, J.H. Couture, 1992
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Radio Amateur's Handbook, 1972
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Elements of Physics, 1964
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Articles:
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----------
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Popular Electronics, Make Your Own High Voltage Capacitors,
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Anthony charlton.
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=======================================================================
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WARNING:
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Only people who are experienced with High Voltage devices should
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attempt to build Tesla Coils. They can be very deadly if you don't
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know what your doing. Remember, if they find you on the floor
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turning blue and frothing at the mouth - THERE IS NO SECOND CHANCE!
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A FEW Safety Tips:
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1. Don't ever touch the machine when it is pluged in.
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2. Use a safe methode to short out the primary capacitor after the
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machine has been run.
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3. Don't ever get close to a running Tesla coil, the Primary can
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shoot hot white arcs at you that will kill you instantly!
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4. Always have a small fire extinguisher close by.
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5. Always use kickback preventer circuits so you don't send
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15,000 volts back through the wall!
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6. Pets, children, and irresponsible adults should be kept away from
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your machine intirely!!!
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7. Read many books on Tesla Coils and other High Voltage devices
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and learn as much as you can about High Voltage Safety!
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8. Review the FIDO text files compiled by Richard T. Quick II
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=======================================================================
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Special thanks to Bert Pool who caught some glaring errors in the second
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draft and who contributed with an equation of his own.
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I wrote this file because I felt there was a need for some real
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information for those of us who actually build Tesla Coils, as opposed
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to those who just talk of building them (Grin). I will be adding to this
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file from time to time, so watch for updates. I hope it helps you out!
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Jerry Gore, Member of Tesla Coil Builders Association (TCBA),
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International Tesla Coil Society, and the North Dallas
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Texas Tesla Coil Association.
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P.S. Let us not forget the words of Tesla," Let the future tell the
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truth and evaluate each one according to his work and accomplishments.
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The present is theirs, the future, for which I really worked, is mine".
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======================= END OF FILE ===================================
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