Project THOR

In the beginning of the year 1999, I have started a project at the Helsinki University of Technology, High Voltage Laboratory, which has been eventually named "Thor". This project constitutes the thesis of my postgraduate studies for the degree of Licentiate in Technology.

The aim of the project is to design and build a medium-sized Tesla Coil (named Thor too) suitable to perform accurate measurements and research work in general. The task is, therefore, to minimize the number of stochastic and unknown parameters influencing the device functionality. The results of this projects are supposed to facilitate the design and construction of other Tesla Coils to be used for testing of insulating materials, generation of high-voltage pulses, research on natural lightning, and other purposes.

Thor is fed by a stabilized DC power supply, which is required to output 20 kV at 5 kW. As the price of commercially available power supplies with these capabilities exceeds easily $30000, this projects includes also the design and practical construction of such a device.

For a description of the design criteria that led to the selection of the Tesla transformer topology and size, the power supply topology and the spark gap type, please read the Design Guidelines.

Project history and status


Thor technical data

Thor related links

Power supply voltage variable from 0 to 20 kV DC
power 5 kW (i.e. 5 kJ/s)
pulse rate up to 500 Hz
Primary capacitor 0.0967 F
inductance 99.1 H (max)
Secondary height 150 cm
diameter 40 cm
inductance 80.2 mH (DC)
capacitance 74.4 pF*
Top terminal shape toroid
outer diameter 150 cm
cross section 20 cm
capacitance 57 pF**
Spark gap type Rotating, 4 gaps in series
Resonance frequency with top load 65.56 kHz
Output voltage simulated 600 kV max

* including the top terminal capacitance
** approximate

About the degree of Licentiate in Technology (adapted from the Helsinki University of Technology Degree Regulations)

In studies for the degree of Licentiate in Technology, the student shall:

1) become thoroughly familiar with his or her own field of research, and able to apply scientific research methods independently and critically within the research field;
2) become familiar with areas of science and technology related to his or her own research field, and with their research and planning methods, and
3) learn about the development, social significance, environmental effects and scientific theory of the areas of science and technology related to his or her own field of research.

The extent of the Licentiate in Technology degree is 80 credits, of which the licentiate thesis constitutes 35 credits. Postgraduate studies shall be organised which:

1) are more extensive and thorough than the Master's studies in the research area of the degree programme; this is known as the major subject of the postgraduate degree (25 - 30 credits); and
2) cover at least one other research area which supports the major subject; this is known as the minor postgraduate subject (10 - 15 credits).

Teaching to support the research of the postgraduate student shall be organised, at least partly in the form of lectures and seminars.
As an additional minor subject (about 10 credits), a further subject may be selected that complements the major or minor studies.
Postgraduate studies may also include other scientific studies (0 - 10 credits).