Re: Grounding Question

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Emmett,

In my opinion, the Safety gap ground should be connected directly to the NST
case.  The safety gap is intended to protect the NST output bushings with
respect to its center tap which is connected to the case.  This direct
connection, I believe, will provide the best protection.  The Terry filter
ground should also be connected directly to the NST case for the same
reason.

The NST case should then be connected to the RF ground and NOT power safety
gound.  The power safety ground should connect to the ground of your line
filter and stop there.  This seems to be convention and others may have
different reasons for this.  The one I am thinking of is in case there is a
secondary discharge to the primary circuit, the return current will be
allowed to go directly back to the secondary's base and not thru the
transformer and into the safety ground.

The secondary coil's base, as you already stated, should be directly
grounded to earth ground via a grounding rod (aka RF ground) again to allow
return currents of secondary discharges to free space or to other objects
grounded to earth to return directly to the secondary base and not return
thru safety ground.

 > Original poster: "EMMETT SECREST" <secrest2032-at-msn-dot-com>
 >
 > Hello All,
 > I am confused on the proper grounding for my first TC.  If someone would
be
 > so kind as to clear it up for me I would appreciate the help. I know the
 > secondary RF ground should be a separate ground. Where I am confused is
the
 > ground for the safety gap on the Terry Filter.
 > 1.Does the Safety gap ground tie in with the secondary RF ground?

In essense, YES

 >
 > 2.Also I have a ground to the NST from the 120VAC supply. Should this
 > ground also attach to the Safety Gap ground or should the supply ground
 > stop at the NST housing.

Do NOT connect NST case to power ground.
 >
 > I apoligize for asking what is I'm sure a very basic question of such a
 > learned group of people. But if you don't ask you don't learn.
 >
 > I considered not even running a ground to the NST from the supply AC and
 > attaching the NSTchassis, RF,strike rail and Safety Gap grounds all
 > together. MY thinking was that that would protect everything in case of a
 > primary strike from the secondary.

GOOD.  NST chassis, secondary base, safety gap grounds, and strike rail
should all be connected to RF (earth grounding rod) ground.

 >
 > 3. Does it matter if the strike rail is a continuos piece of copper
tubing?
 > I spliced the ends together to add better support to the copper tubing.

YES it matters,  do NOT close the loop of the strike rail otherwise you will
have (in effect) a shorted turn in the vicinity of the primary where the
fields are the strongest.  Induced currents in this loop will suck a lot of
energy from the primary and kill a good part of the field the primary
creates.  Make a gap in the strike rail loop sufficiently wide enough so
arcing across the gap does not occur.

Gerry R
Ft Collins, CO