Re: Arc'ing in my variac

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Edward Wingate <ewing7-at-rochester.rr-dot-com> 

Tesla list wrote:
 >
 > Original poster: Pat Masterson <bat-at-grumman-dot-com>
 >
 > I was tuning my small coil (15/30 NST) and noticed little sparks dancing
 > around the windings of my variac. Is there something fundamentally wrong
 > with the setup, or do I need an RFI filter between the variac and the
 > NST? The variac is an older model, and has no 3rd wire (ground) on its
 > AC line.  -pat

Pat,

It sounds to me like your coil is out of tune and you're getting
kickback into the Variac. Continued operation in that mode will
eventually destroy your Variac and possibly, if you don't happen to have
an EMI filter between the line and the Variac, any other devices you may
have on that line.

Regards,

Ed Wingate RATCB