My HTC Tesla Coil

The HTC Tesla Coil was commissioned to me by a Finnish museum and is featured in a permanent exhibition since beginning of 2007.
The HTC Technical Manual provides technical details, measurements and schematics.

While resembling pretty much my first Tesla Coil, it uses a number of different solutions.

Push-and-twist secondary mount

The secondary is secured to the general structure through a slotted insert. The base grounding contact is achieved by two copper plates, one with the secondary winding bottom soldered from the pipe inside, the other grounded with a wide copper strap. The insert slot bottom table features 8 springs so that mounting the secondary in place requires only a simple "push and twist" movement.

Upside down primary

The primary winding is mounted below an acrylic table. The wires connecting to it as well as the winding itself are slightly more protected against discharges coming directly from the top toroid. No strike rail is employed.

Full protection of the HTC guts

This time all the HTC supply, RSG, filters, etc. is fully shielded against possible discharges by four grounded panels made out of a thight iron mesh, with aluminum L-profile borders. I didn't notice any reduction in performance by adding this shielding. Anyway, I took a good care not to create any loop or turn by connecting the four sides in a "star topology" to the general HTC ground.

The RSG

The RSG is a much more conventional design. A bakelite disk features a brass ring shorting 6 tungsten electrodes (TIG welding electrodes). The electrodes mounting pieces are made using brass bolts drilled longitudinally. Two radial threaded holes in the head of each of the bolts allow to keep the electrodes firmly in place using Allen screws. Motion is provided by a small 1 hp 230 Vac motor.
The rotor has been hand-balanced using small tuning screws by mounting it first on a brass axle and a jig with decent quality ball-bearings.