Dec 312017

Computer aided design for Tesla Coils. | |||
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TCAD.TXT | 10624 | 4216 | deflated |

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## Contents of the TCAD.TXT file

THEORETICAL ELECTROMAGNETIC STUDIES AND LEARNING ASSOCIATION

522 WEST THIRD STREET

LEADVILLE, CO 80461

(719) 486-0133

COMPUTER AIDED DESIGN OF TESLA COILS

BY

TOBY GROTZ

Coil Tuning & CAE Comparisons Of Three Similar Coils

Software for Tesla Coil design has only recently become available.

Computer Aided Engineering using appropriate software not only helps

during the initial design but helps to refine system operating

characteristics. We have used three programs for Tesla Coil design.

One of the first was developed by Kovak1-7 and was written for

Commodore-64, Apple II-e and Sharp computers. The program has

excellent graphics and contains separate sections on design theory and

the mathematics of Tesla Coil design. The program is supplemented with

a video for VHS or BETA which details design examples and use of the

program. (see TCBA NEWS Vol. 4, #1, pg. 3, 1985) One word of caution:

the calculation for the resonant frequency of the secondary may differ

from measured values by a significant amount. This program provides an

excellent introduction into Tesla Coil design and construction for

amateur experimenters and students beginning their study of Tesla Coil

design, but it does not take into account calculations for the extra

coil.

TSCAD by Robert Jamison1-8 is the most comprehensive and

sophisticated program that we have reviewed to date. The program

features improved scaling for unusual conditions, an expanded entry

range, and comes with a comprehensive manual with multiple hardware

examples. The program, in my opinion, is not for beginners, but for

experienced builders and design engineers. This program is quite

versatile in its ability to allow "what if" inputs. The main screen

which contains the electrical and physical parameters permits easy

entry of new values and allows a designer to quickly change many

parameters leading to a fast and easy design. Help screens and

comments are readily available as well a a built in commentary which

points out design discrepancies and offers suggestions for re-design.

After several sessions of running TSCAD, I remembered the first time I

sat down at a computer to run a Tesla Coil design program. I am

amazed at how far Tesla Coil CAD has come in five years. TSCAD blends

the art of Tesla Coil construction into the science of electrical

design.

TCTUTOR by James F. Corum and Kenneth L. Corum1-9 is a program that

does to Tesla Coil design what the 6502 did for personal computing.

Running on a PC, the program will be appreciated by engineers, hardware

designers, and students of electrical power and RF theory. The program

is attractively and professionally packaged with a three ring binder

that contains program instructions and a comprehensive dissertation,

Tesla Coils - An RF Power Processing Tutorial For Engineers. The

theory of Tesla Coil design begins with elementary principles of

resonance and continues up through graduate level course work. TCTUTOR

is a program that can be used at any level to demonstrate the

principles under study. The program calculates wave forms, spectral

power distribution through the use of a fast fourier transform (FFT),

and performs Smith Chart calculations for the case of the extra coil.

(Technically the Extra Coil is a quarter wave helical resonator and

mathematical analysis is quite complicated) If or when wireless

transmission of power is finally attempted, it is to be expected that

TCTUTOR will play a part in the final design.

Because it is the only program that allows for Extra Coil design and

analysis, we have used TCTUTOR to compare and contrast three of the

largest Tesla Coils built to date. The first, of course was described

by Nikola Tesla in The Colorado Springs notes of 18991-10. The second

and third coils are those built in Colorado and Utah and described

above. Using the measured and assumed values in Table I, print outs

from TCTUTOR show the voltage induced from primary excitation, the

Fourier Spectrum of the induced voltage, and the final output voltage

and extra coil characteristics, for all three cases.

TABLE I

Tesla - 1899 Utah Colorado

Input Voltage (kv rms) 70 44 45

Capacitance in Primary Circuit (C1 uf) .127 .2 .177

Primary Resistance (R1 ohms) 8 * *

Primary Inductance (L1 uh) 57 33 33

Secondary Inductance (L2 mH) 9 9 9

Secondary Resistance (R2 ohms) 10 * *

Secondary Capacitance (C2 pf) 300 * *

Secondary Resonant Frequency (kHz) 97 64 64

Extra Coil Resonant Frequency 92 94 94

Coefficient Of Coupling .6 .6 *

(*) indicates that the quantity was not measured, the default program

value was used in the analysis. R1 & R2 are AC resistances at the

frequency of operation. Since minimal data was available for the Utah

configuration1-11, an assumption of values was based on the fact that

the Colorado system had been built as close as possible to that used in

Utah, which in turn had been built electrically and physically as close

to the the Colorado Springs design as possible. The coil dimensions

were the same and the length of wire used in the primary, secondary,

and extra coil was the same. As a matter of fact, the same wire used

for the Utah experiments was used for the recent experiments in

Colorado.

Figures 1 - 9 show the computer analysis based on values presented in

Table I. The first four figures show the output of TCTUTOR for the

values Tesla used in 1899. Figures 6 - 9 show the Fourier Spectrum and

the peak voltage induced in the secondary for both the Utah ( Figs 6 &

7) and Colorado (Figs 8 & 9) experiments.

FIGURES - FROM TCTUTOR

Fig. 1. Circuit diagram with values used by Tesla in 1899.

Fig. 2. The equivalent lumped circuit of the secondary. 1899

Fig. 3. Induced Secondary voltage vs. time. 1899

Fig. 4. The Fourier Spectrum if the induced voltage. 1899

Fig. 5. The final output from the extra coil with Smith Chart factors,

calculated voltage step up, and estimated spark length. 1899

Fig. 6. Fourier Spectrum, Utah experiments.

Fig. 7. Induced voltage, Utah experiments.

Fig. 8. Fourier Spectrum, Colorado experiments.

Fig. 9. Induced Voltage, Colorado experiments.

PHOTOGRAPHS

1. QUENCH GAP Barrel covering top half is a safety measure in case of

rupture due to ceramic failure while pressurized. (see text)

2. ROTARY BREAK turns at 7110 rpm and breaks 2370 times per second.

3. PRIMARY AND SECONDARY note height of primary above floor, also

standoff insulators and heavy wire used on the upper most turn of the

secondary.

4. EXTRA COIL showing PVC construction and standoffs used on first and

last turns, note also the sloped design used on the upper section.

5. CAPACITORS connected in series, total capacitance, .177 uf.

6. TRANSFORMERS used in step up step down step configuration.

7. SPARKS output from the extra coil.

8. TOWER constructed as described in the article, note size compared to

extra coil.

As stated above, in the initial summary, two reasons for poor coil

performance are given: over loading and poor tuning. As can be seen

from the data obtained using TCTUTOR, the fact that the secondary and

extra coil are tuned so far apart, contributes greatly to degraded coil

performance. The supposition that the secondary and extra coil must be

"detuned"1-12, in order for the system to work cannot be explained by

the author. Any explanations or suggestions to explain this oft

repeated statement would be appreciated.

In the future, more accurate measurements will be made and the coil

will be properly tuned. All parameters will be measured and checked

against the values given in the Colorado Springs notes. The

observation to be made here is the difference between the experiments

of 1899 and those of Utah and Colorado. As can be seen from the graphs

of frequency distribution, Tesla's coil was a masterpiece of fine

tuning.

FOOT NOTES

1-7. Kovak, Ron, "Ball Lightning Research Via Computer Tesla Coil

Design", Astro Electronics Corporation, 1165 Hancock, Boulder, CO,

(303) 444-5447. (Also contains photographs and speculation about Ball

Lightning)

1-8. TSCAD, Robert M. Jamison, 6809 Mayfield, #1554, Mayfield Hts.,

Ohio, 44124.

1-9. TCTUTOR, Corum & Associates, 8551 State Route 534, Windsor, Ohio,

44099, (216) 272-5722.

1-10. Nikola Tesla, Colorado Springs Notes, 1899-1900, Nolit, Beograd,

Yugoslavia, 1978. (Available from the Tesla Book Company)

1-11. Golka, Bob, "Long Arc Simulated Attachment Testing Using A 150KW

Tesla Coil", Golka & Associates, 400 Warren Avenue, Brockton, MA 02403.

1-12. Golka, 1987, 1988.

TESLA BULLETIN BOARD SERVICE (TESLA BBS) Networking, results of

research, on going dialog etc. Supports 300/1200/2400 Baud, Phone

Number 719-486-2775 data, 719-486-0133 voice.

522 WEST THIRD STREET

LEADVILLE, CO 80461

(719) 486-0133

COMPUTER AIDED DESIGN OF TESLA COILS

BY

TOBY GROTZ

Coil Tuning & CAE Comparisons Of Three Similar Coils

Software for Tesla Coil design has only recently become available.

Computer Aided Engineering using appropriate software not only helps

during the initial design but helps to refine system operating

characteristics. We have used three programs for Tesla Coil design.

One of the first was developed by Kovak1-7 and was written for

Commodore-64, Apple II-e and Sharp computers. The program has

excellent graphics and contains separate sections on design theory and

the mathematics of Tesla Coil design. The program is supplemented with

a video for VHS or BETA which details design examples and use of the

program. (see TCBA NEWS Vol. 4, #1, pg. 3, 1985) One word of caution:

the calculation for the resonant frequency of the secondary may differ

from measured values by a significant amount. This program provides an

excellent introduction into Tesla Coil design and construction for

amateur experimenters and students beginning their study of Tesla Coil

design, but it does not take into account calculations for the extra

coil.

TSCAD by Robert Jamison1-8 is the most comprehensive and

sophisticated program that we have reviewed to date. The program

features improved scaling for unusual conditions, an expanded entry

range, and comes with a comprehensive manual with multiple hardware

examples. The program, in my opinion, is not for beginners, but for

experienced builders and design engineers. This program is quite

versatile in its ability to allow "what if" inputs. The main screen

which contains the electrical and physical parameters permits easy

entry of new values and allows a designer to quickly change many

parameters leading to a fast and easy design. Help screens and

comments are readily available as well a a built in commentary which

points out design discrepancies and offers suggestions for re-design.

After several sessions of running TSCAD, I remembered the first time I

sat down at a computer to run a Tesla Coil design program. I am

amazed at how far Tesla Coil CAD has come in five years. TSCAD blends

the art of Tesla Coil construction into the science of electrical

design.

TCTUTOR by James F. Corum and Kenneth L. Corum1-9 is a program that

does to Tesla Coil design what the 6502 did for personal computing.

Running on a PC, the program will be appreciated by engineers, hardware

designers, and students of electrical power and RF theory. The program

is attractively and professionally packaged with a three ring binder

that contains program instructions and a comprehensive dissertation,

Tesla Coils - An RF Power Processing Tutorial For Engineers. The

theory of Tesla Coil design begins with elementary principles of

resonance and continues up through graduate level course work. TCTUTOR

is a program that can be used at any level to demonstrate the

principles under study. The program calculates wave forms, spectral

power distribution through the use of a fast fourier transform (FFT),

and performs Smith Chart calculations for the case of the extra coil.

(Technically the Extra Coil is a quarter wave helical resonator and

mathematical analysis is quite complicated) If or when wireless

transmission of power is finally attempted, it is to be expected that

TCTUTOR will play a part in the final design.

Because it is the only program that allows for Extra Coil design and

analysis, we have used TCTUTOR to compare and contrast three of the

largest Tesla Coils built to date. The first, of course was described

by Nikola Tesla in The Colorado Springs notes of 18991-10. The second

and third coils are those built in Colorado and Utah and described

above. Using the measured and assumed values in Table I, print outs

from TCTUTOR show the voltage induced from primary excitation, the

Fourier Spectrum of the induced voltage, and the final output voltage

and extra coil characteristics, for all three cases.

TABLE I

Tesla - 1899 Utah Colorado

Input Voltage (kv rms) 70 44 45

Capacitance in Primary Circuit (C1 uf) .127 .2 .177

Primary Resistance (R1 ohms) 8 * *

Primary Inductance (L1 uh) 57 33 33

Secondary Inductance (L2 mH) 9 9 9

Secondary Resistance (R2 ohms) 10 * *

Secondary Capacitance (C2 pf) 300 * *

Secondary Resonant Frequency (kHz) 97 64 64

Extra Coil Resonant Frequency 92 94 94

Coefficient Of Coupling .6 .6 *

(*) indicates that the quantity was not measured, the default program

value was used in the analysis. R1 & R2 are AC resistances at the

frequency of operation. Since minimal data was available for the Utah

configuration1-11, an assumption of values was based on the fact that

the Colorado system had been built as close as possible to that used in

Utah, which in turn had been built electrically and physically as close

to the the Colorado Springs design as possible. The coil dimensions

were the same and the length of wire used in the primary, secondary,

and extra coil was the same. As a matter of fact, the same wire used

for the Utah experiments was used for the recent experiments in

Colorado.

Figures 1 - 9 show the computer analysis based on values presented in

Table I. The first four figures show the output of TCTUTOR for the

values Tesla used in 1899. Figures 6 - 9 show the Fourier Spectrum and

the peak voltage induced in the secondary for both the Utah ( Figs 6 &

7) and Colorado (Figs 8 & 9) experiments.

FIGURES - FROM TCTUTOR

Fig. 1. Circuit diagram with values used by Tesla in 1899.

Fig. 2. The equivalent lumped circuit of the secondary. 1899

Fig. 3. Induced Secondary voltage vs. time. 1899

Fig. 4. The Fourier Spectrum if the induced voltage. 1899

Fig. 5. The final output from the extra coil with Smith Chart factors,

calculated voltage step up, and estimated spark length. 1899

Fig. 6. Fourier Spectrum, Utah experiments.

Fig. 7. Induced voltage, Utah experiments.

Fig. 8. Fourier Spectrum, Colorado experiments.

Fig. 9. Induced Voltage, Colorado experiments.

PHOTOGRAPHS

1. QUENCH GAP Barrel covering top half is a safety measure in case of

rupture due to ceramic failure while pressurized. (see text)

2. ROTARY BREAK turns at 7110 rpm and breaks 2370 times per second.

3. PRIMARY AND SECONDARY note height of primary above floor, also

standoff insulators and heavy wire used on the upper most turn of the

secondary.

4. EXTRA COIL showing PVC construction and standoffs used on first and

last turns, note also the sloped design used on the upper section.

5. CAPACITORS connected in series, total capacitance, .177 uf.

6. TRANSFORMERS used in step up step down step configuration.

7. SPARKS output from the extra coil.

8. TOWER constructed as described in the article, note size compared to

extra coil.

As stated above, in the initial summary, two reasons for poor coil

performance are given: over loading and poor tuning. As can be seen

from the data obtained using TCTUTOR, the fact that the secondary and

extra coil are tuned so far apart, contributes greatly to degraded coil

performance. The supposition that the secondary and extra coil must be

"detuned"1-12, in order for the system to work cannot be explained by

the author. Any explanations or suggestions to explain this oft

repeated statement would be appreciated.

In the future, more accurate measurements will be made and the coil

will be properly tuned. All parameters will be measured and checked

against the values given in the Colorado Springs notes. The

observation to be made here is the difference between the experiments

of 1899 and those of Utah and Colorado. As can be seen from the graphs

of frequency distribution, Tesla's coil was a masterpiece of fine

tuning.

FOOT NOTES

1-7. Kovak, Ron, "Ball Lightning Research Via Computer Tesla Coil

Design", Astro Electronics Corporation, 1165 Hancock, Boulder, CO,

(303) 444-5447. (Also contains photographs and speculation about Ball

Lightning)

1-8. TSCAD, Robert M. Jamison, 6809 Mayfield, #1554, Mayfield Hts.,

Ohio, 44124.

1-9. TCTUTOR, Corum & Associates, 8551 State Route 534, Windsor, Ohio,

44099, (216) 272-5722.

1-10. Nikola Tesla, Colorado Springs Notes, 1899-1900, Nolit, Beograd,

Yugoslavia, 1978. (Available from the Tesla Book Company)

1-11. Golka, Bob, "Long Arc Simulated Attachment Testing Using A 150KW

Tesla Coil", Golka & Associates, 400 Warren Avenue, Brockton, MA 02403.

1-12. Golka, 1987, 1988.

TESLA BULLETIN BOARD SERVICE (TESLA BBS) Networking, results of

research, on going dialog etc. Supports 300/1200/2400 Baud, Phone

Number 719-486-2775 data, 719-486-0133 voice.

December 31, 2017
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