Re: Filters for non - NST primary

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Kurt Schraner" <k.schraner@xxxxxxxxxxx>

Hi,

this is my version of a crude "Terry filter" for 
my big coil B&W (please view in fixed font; hope it will work):


          10m RG213 ...C=1nF
       ----------------------  .5k/200W        Prim C
  HV o-------------------------RRRRRRR--.-----.---¦¦-->
       ----------------------           ¦     ¦
                                        ¦     ¦
4PT's/16kVeff (P~12kVA)                  o     ¦   Prim L
                                 safety o   SRSG

          10m RG213 ...C=1nF            ¦     ¦
       ----------------------           ¦     ¦
  HV o-------------------------RRRRRRR--.-----.------->
       ----------------------  .5k/200W
         RG213 shield /


Without the resistors, I had some heavy 
overvoltage effects at the PT's, probably by 
Blumlein transmission line effects, repeatedly 
mentioned by D.C.Cox(Dr.R) on this list (I hope, 
he don't condemn me for not taking off the shield 
;-)). But the R's made everything smooth! Instead 
of looking at the RG213 cables as transmission 
lines, I just took them as 10m-long capacitor, lumped elements...

BTW: I was honoured to display my bigger coil 
"Black & White" on July 14th at the University of 
Bern festivities for Einstein. Bern 1905, the 
place and year, when Einstein developed and 
published some of his most important theories 
about modern physics. For the coil see:
http://home.datacomm.ch/k.schraner/B&Wbei EinsteinBE.jpg
http://home.datacomm.ch/k.schraner/16425Stadt20050716_1.pdf

Best Regards,
Kurt

----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, October 14, 2005 4:55 AM
Subject: RE: Filters for non - NST primary


> Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
>
> Charging current is far higher from a pig and would probably fry the
> resistors.  Also, should the cap selection or other variables cause the
> charging voltage to go too high, the MOV's would quickly fry.
>
> As far as pigs on the web using chokes, all I can say is don't believe
> everything you read on the web.  Pigs are bulletproof compared to NST's
> and need no external protection, but you can add chokes if you think
> they look nice.
>
> Regards, Gary Lau
> MA, USA
>
>
> > Original poster: FIFTYGUY@xxxxxxx
> >
> > In a message dated 10/13/05 10:17:51 AM Eastern Daylight Time,
> > tesla@xxxxxxxxxx writes:
> >
> >  > The Terry filter is only for NSTs.
> >
> >      How come? Why would it be unsuitable for a pig, MOT, PT, etc.? I
> > don't see how it could hurt.
> >      IIRC the pig setups I've seen on the Web *do* use the filtering
> > chokes on the secondary lines. I understand weird resonances and
> > other problems can occur with shunted transformers, such as NSTs,
> > when using filter chokes. Has anybody determined if they are of
> > harm/benefit on the larger systems?
> >
> > -Phil LaBudde
> >