Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx> Hi Jim,You can of course use other metals, but there are conditions you will run into when using common fasteners. Corona is a product of high voltage devices and is very corrosive. As parts corrode and pit away, there are layers of insulation which build within the pitting. This reduces conductivity (contact surface is diminished). Granted, the coil will work fine for a while (or maybe even a long period depending on the corona emitted and the overall time the system is ran), but it is nice to use highly conductive materials not prone to corona corrosion.
The sparkgap due to it's high current and high voltage will pit very quickly and transfer material between adjacent tubes. Even copper and brass will show the signs. But with the gap, it's easy enough to clean giving the tubes a new face. Thermal conduction is a more important factor for gaps. A thin walled tubing is much faster at heating and cooling. Thicker walled tubing will of course be slower at this. A fan is very helpful for stabilizing the thermal conduction for the power dissipated in the form of heat at the electrodes. The cooler, the better (the whole idea is to have the voltage breakdown as high as possible within the design specs). Heat reduces the voltage required to arc the gap equating to less energy for spark production.
Quenching, without going into a lot of detail, is simply a point in time when the gap stops conducting. In theory, we want the gap to stop conducting within the 1st primary notch (unless quenching too quickly forces losses elsewhere). In most systems, the gap will quench on the 2nd or 3rd primary notch of the ring cycle which begins when the gap conducts and ends when there is no longer enough energy to keep the gap conducting (quench). The ring cycle frequency is the LC circuit frequency of the tank cap and the primary which the gap conduction switches on. The LC circuit is of course resonant with the secondary frequency.
Here is a quick pop up help file from Javatc that will show simulation waveforms and a real scope capture of quenching. This particular help file is for a Javatc output identifying the number of half cycles required for full energy transfer. It will further explain quenching.
http://www.classictesla.com/java/script/out28.html Take care, Bart Tesla list wrote:
Original poster: Jim <branley1@xxxxxxxxxxx> Hi Folks:I do appreciate the great assistance with my tesla coil that I have received from you.Can I get your opinion on a few things?1) Can I use 1" EMT (Electrical Metallic Tubing) for my spark gap instead of 1" copper pipe?2) Can I use zinc coated bolts and nuts for my secondary instead of brass bolts and nuts? Zinc is what most bolts, nuts & washers are coated with.3) What does the term quenching refer to when speaking about spark gaps? Thanks for the informative help! Jim