RE: [TCML] Terry Filter Gound

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

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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