Medium Sized Tesla Coil

RATCB Teslathon 2002

most photos are from video

The Medium Tesla coil is 25" tall with a base that is 18" x 24".
The 4"x22" secondary is PVC wound with #26 magnet wire.
The 13 turn, flat-spiral primary is 1/4" copper water tubing, tuned with a clamp.
The toroid is a 12" x 3" spun aluminum from Information Unlimited.
The cap is a 0.015 uF @45 KV Maxwell.
The power supply is a 14.4KV (1.5 KVA rated) Potential Transformer.
Current limiting is provided by a 500 foot roll of 12 Gauge wire.

Multiple rotary spark gaps used.
120 BPS SRSG, 240 BPS SRSG, an ARSG.

Rotary Spark Gaps

The Beast, up close.

It was very damp out and I was getting racing sparks on the secondary.
I had some help from fellow coilers to reduce coupling with a CD case.

Gotta have a target

Maxwell 0.015 uF capacitor and 120 BPS rotary spark gap
The 240 BPS rotor is to the right and above the motor

Maxwell 0.015 uF capacitor and 240 BPS rotary spark gap

240 BPS rotary spark spark gap that requires no Tungsten cutting
and no working with G10, balancing, lathes, and other hard to do stuff

asynchronous rotary spark gap that requires some Tungsten cutting
but not much other hard stuff

Fellow coiler checking for heat buildup in current limiting ballast.
He says "slightly warm".

The ballast. 0.9 Ohms 10.50 mH.

Air core. Current limits to about 25 A. About $20, off-the-shelf, from Home Depot.

This is the Potential Transformer. Weighs in at 95 pounds. Rated at 1.5 KVA.

This is the variac with full-metering and built-in 60A EMI filter.
At maximum voltage, the current limits to about 25 A (with ballast).

It was intended for 240 V and 15 A (4.2 KVA). But I use it at 120 and 30 A.