Re: SGTC

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Christoph Bohr" <cb@xxxxxxxxxxxxxxx>

Hello DrR, folks.

> Even PT and pole xmfrs need a protection circuit if you want to keep
> the high freq currents out of the secondary windings --- you only
> want 60 Hz current there.  The HF currents form "spiders" tracking
> across the HV windings and can lead to break down of the sec
> winding.  These are caused RF which likes to "track" across insulator
> surfaces.  Not good inside a power xmfr.  Pole xmfrs will tolerate
> some abuse but good design says to eliminate the problem before it
> occurs --- prevention.
OK, with my homemade transformer, I obviously got away without a filter
over the last two years, but your comment sounded my alarm bells.
Now, how would I size a filter for my xformer, measured at 13500V ca 400mA out,
usually running at around 5KVA.( single ended )
I am not the math guy, but I tried to do some calcs and found,
that with a lets say 1nF doorknob and 1KOhm resistance the filter
will cut off around several hundred KHz, isn't that way to high? I would have
aimed for something over several KHz.... am I missing something.
What layout would you suggest, I hoped to get away without another MMC in the
filter, would rahter use some doorknob stype cap there...
Any suggestions are appreciated....

best regards

Christoph Bohr