[TCML] Terry Filter Gound
bartb at classictesla.com
Tue Mar 10 19:53:16 MST 2009
I agree and we've said so many times on the TCML.
Bonding is absolutely required (mains to case) in all consumer circuits.
But too often, coilers take this "bonding issue" without common sense
(applying it to everything). A Tesla Coil is not an appliance. You of
course can hook mains ground to the NST case, safety gap, etc. But if
you do, you have just directly connected every high voltage nasty
transient the coil will spit out (and it will in abundance) to every
appliance in your house (Xbox360's, TV's, VCR's, Computers, Washing and
Drying machines, Coffee Pot, Clocks, etc..).
Don't do that. Instead, tie RF ground to the Terry filter safety gap and
to the NST case. This will direct those nasty transients to the
dedicated RF ground. But with that, you must ensure that you never
handle your NST with power applied. This is an important safety rule
that must be maintained.
If your ok with killing your household items, then sure, hook up mains
ground to your NST. No problem. Just don't come crying to me when "bad"
I went though many years never losing anything in my house (because I
didn't have a lot to lose I guess). But eventually, I lost a sound card,
a video card, and an Xbox360 (just my personal experiences). Others have
killed various electronics. "Separating" mains ground from hv garbage in
a TC system is highly recommended. One of the best ways to do this is
without a direct connection.
Lau, Gary wrote:
> 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 at pupman.com [mailto:tesla-bounces at pupman.com] 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 at yesbossmusic.com>
>> To: Tesla Coil Mailing List <tesla at pupman.com>
>> 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.
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