Hi Scott,The NST is probably the weakest link when it comes to hv transients or even sustained high voltages. This is why the Terry Filter was designed by Terry Fritz. The NST is a transformer that is great to use for coils due to it's voltage and current, but it is of poor construction when it comes to over-volting. Thus, a fileter to prevent those transients is good medicine and Terry Fritz designed such a filter for NST's. Another pill is to run LTR on the cap size. This keeps the bang energy high and keeps the cap from resonating with the transformer which can over-volt the NST. A mains filter is also a plus. I use both a mains filter, and Terry Filter, and I run near LTR for my coils when possible.
If you want to protect your NST, the above are the basics. Here's the Terry Filter data.
http://www.classictesla.com/download/NST_Filter.jpgFor my filter, I simply layed out all the components on a pc board that would fill the area of a plastic box I had. The board included everything except the two large resistors of which I mounted on top of the box.
http://www.classictesla.com/photos/ba45/s2748.jpgYou can see the filter box on top of the NST in that image. Note the two high watt resistors and also note the safety gap center to the resistors. These are all part of Terry's filter circuit. We all do it a little differently. This is what I did.
Take care, Bart Scott wrote:
Hello again guys. The troubleshooting tips I got here on my first post led me to replace my NST and as a result my coil is now resonating, thanks to all. Now that I'm onto tuning, I would like to protect the power supply systems before I do any runs longer than a few seconds. The construction of a safety gap, variable power output, ext. are within my technical grasp, but I would like some advice on a choice of filter.
_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla