RE: [TCML] Terry Filter Gound

["Lau, Gary" <Gary.Lau@xxxxxx>]

While connecting the RF ground to the mains ground is "probably" not a good idea (depending upon the power of the coil), it may or may not explain the tingling sensation.  I've not personally experienced it, but I've heard others running VTTC's and solid state TC's, report receiving shocks from a _properly_ mains-grounded Variac case.  This is just because their bodies are capacitively coupled to the top load, and touching the case completes the circuit to ground.  

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of otmaskin5@xxxxxxx
> Sent: Thursday, March 12, 2009 6:25 PM
> To: tesla@xxxxxxxxxx
> Subject: Re: [TCML] Terry Filter Gound
> 
> Looking at your schematic, Gary, now I think I know why I've been getting tingly
> sensations off my variac.? I had the variac case grounded to the house mains
> ground and also connected to the ground on the line filter.? Gotta move the later to
> the RF ground.? Thanks!? Dennis Hopkinton MA
> 
> 
> 
> 
> 
> 
> 
> -----Original Message-----
> From: Lau, Gary <Gary.Lau@xxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Tue, 10 Mar 2009 3:58 pm
> Subject: RE: [TCML] Terry Filter Gound
> 
> 
> 
> NO!  In a midpoint-grounded NST, the NST case and HV winding midpoint connect
> to
> the RF ground, same place as the Terry filter ground.  The mains ground goes
> only as far as the Variac case - things that one would reasonably touch while
> the coil is operating.
> 
> When an NST is used to power a neon sign, it's reasonable to expect that one
> might touch the NST case, so it needs to be tied to earth ground for safety.
> But as the NST case in a Tesla coil circuit must be tied to RF ground, you can't
> have it both ways, so don't touch the NST case while your coil is powered up.
> 
> Schematics of my coils here:  http://www.laushaus.com/tesla/myschematics.htm
> And Terry filter stuff: http://www.laushaus.com/tesla/protection.htm
> 
> Regards, Gary Lau
> MA, USA
> 
> > -----Original Message-----
> > From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> > Behalf Of James Howells
> > Sent: Tuesday, March 10, 2009 3:30 PM
> > To: Tesla Coil Mailing List
> > Subject: Re: [TCML] Terry Filter Gound
> >
> > The NST mains ground goes to mains earth
> > Every thing from the HV side including the safety gap Tery filter goes to
> Actual
> > earth / ground / stake in the soil
> > ________________________________
> > From: Simon Dodd <simon@xxxxxxxxxxxxxxxx>
> > To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> > Sent: Tuesday, 10 March, 2009 19:08:54
> > Subject: [TCML] Terry Filter Gound
> >
> > Hi Guys,
> >
> > I'm a little bit confused about the ground from the Terry Filter.  All the
> schematics
> > and pictures I have seen have indicated connecting the ground of the safety
> gap to
> > RF ground and also running it back to the NST ground.
> >
> > However everything else I have read has stated expressly not to connect the
> NST
> > to the same RF ground as the Tesla coil.  The only thing I can think of is to
> not
> > connect the NST to the mains earth and keep it only on the RF ground.
> >
> > Thanks
> >
> >
> > Simon
> 
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