If one studies the subject one finds the following key design considerations:
- Using hard graphite carbon rods (made like pencil leads) and a voltage of 45 to 60 volts with about 2 to 10 amps DC in a semi-closed
environment (behind glass, with controlled air flow) consumes the least amount of carbon rod.
- DC works best but AC can be used. Current is limited by use of resistor (DC) or Inductance (AC). This is necessary because of the
negative resistance characteristic of the arc.
- With this in mind, for testing Carbon Arc I purchased two surplus small 70 Volt (open circuit) output transformers that worked on 120 Volts
input. Each one weights about 2 lbs. I wired them in parallel for input and output windings (to give more power) and put a 5 ohm power
resistor in series with the 120 volt input winding. The 5 ohm resistor is to give short circuit protection to the transformers. The short circuiting
the output causes the current flow for input winding to be 6 amps.
- By using jumper clip leads carbon poles from small dry cells and pencil led was tested. One could strike an arc by bring the ends together,
and then separate the electrodes to produce a carbon gas plasma wider arc. The pencil led was a bit thin and didn't last long. It would get
red hot along its length while in operation. This indicated it was running way over current for its small size. Lots of white light was produced
when in operation but for a short time.
Offered by Mike.