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RE: simple question (electrical vs. RF ground)
By no means a simple question. "Electrical ground" generally refers to the
3rd terminal on an electrical outlet. This provides a means to ground fault
currents that might otherwise be hazardous to people. It is intended to be
used only during fault conditions. Electrically, it is connected to the
neutral conductor of your power mains, and to an earth ground, at your fuse
box/ circuit breaker box. In a Tesla Coil system, only the variac case
would connect to this ground.
An "RF ground" is an earth ground, similar to the one connected to your fuse
box, but separate and independent, and dedicated for use by one's coil. It
also should have a very short and heavy connection to minimize inductance
between the Tesla Coil secondary base, and the actual ground. In addition
to the secondary base, the NST case, safety gap center terminal, bypass
capacitor ground, fan housing, strike rail, and anything else likely to be
struck by a streamer would be connected to the RF ground.
At first glance, they appear to be the same thing. However, the 3rd
terminal on outlets is generally a very long way, wire-distance and
inductance-wise, from a true earth connection. If your coil is small or, if
your fuse box has an exceptionally good earth ground, AND if your outlet is
in close proximity to your fuse box, you may be able to use the 3rd terminal
as an RF ground as some do. But most prefer to play it safe and use a
separate RF ground.
Regards, Gary Lau
Waltham, MA USA
-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, November 30, 1999 8:23 PM
To: tesla-at-pupman-dot-com
Subject: simple question
Original Poster: LEST2001-at-aol-dot-com
This is such a simple question I'm embarrassed to ask, but
everyone has been
so helpful. What is the difference between RF ground, and an
electrical
ground?
Thank you,
Leslie