Re: 3 phase pole pig (fwd), Richie's Site back up (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 2 Nov 2007 17:40:32 -0500
From: David Dean <deano@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: 3 phase pole pig (fwd), Richie's Site back up (fwd)

On Friday 02 November 2007 03:05:45 pm you wrote:
> ---------- Forwarded message ----------
> Date: Fri, 02 Nov 2007 15:02:19 +0200
> From: Tomas Stankevic <Tomas.Stankevic@xxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: 3 phase pole pig (fwd), Richie's Site back up (fwd)
>
> Really good site!
> In the 6 pulse design there are 3 separate transformers used, but I am
> going to have one 3phase unit. Is there a difference about it?
Not really. Only from what I can tell you will not have a "N" brought out of 
the case to ground.  You can ground the "n" terminal and not reference the 
high voltage side. Or if the case can be opened you might be able to  
swap "n" with "N" internally.  In any case, you do NOT connect the high 
voltage neutral (N) with the low voltage neutral (n) in a Yy (wye to wye for 
us US electricians) three phase transformer. Ritchie's site shows both 
neutrals connected to ground. That is the normal way of doing things when you 
use three transformers. A three phase transformer is, for all intents and 
purposes, three single phase transformers sharing a single core.  The 
magnetic flux is linked through all three sets of coils, and any imbalance in 
source or load will result in possibly destructive neutral currents with both 
neutrals connected together. So in a three phase transformer only one set of 
windings (hi voltage or low voltage but not both) may be referenced to 
ground. You could of course ground either end of the DC output, or if you use 
a filter capacitor you could put two caps in series and use the midpoint for 
ground to give a + and - supply. Other than the grounding thing there is no 
difference between using three single phase or a single three phase 
transformer in the six point rectifier circuit.

> I am 
> almost sure that it's not going to be any zigzag or smth. In Lithuania
> there are usually 10kV to 0,4kV
> 3 phase transformers with 120deg angle between phases. I dont know what
> other configurations might be.
>
> What about a ballast for it?
>

If you go DC ballast in the input side of the transformer is not really 
needed. A charging inductor  between DC output and spark gap for a 
conventional coil, or one of the interesting rotary gap arrangements that 
have been discussed a time or two would work out just fine. Note however that 
depending on the service/breakers etc. you _might_ have an inrush current 
problem when you power up the transformer as the core is magnetized. If that 
proves to be, then one of the "soft start" solutions would be in order.  If 
you use an energy storage or "filter" capacitor the inrush current will be 
increased and may well become problematic requiring some means of inrush 
current limiting.
 
> Tesla list wrote:
> > ---------- Forwarded message ----------
> > Date: Thu, 1 Nov 2007 19:49:36 -0700
> > From: Jim Mora <jmora@xxxxxxxxxxx>
> > To: 'Tesla list' <tesla@xxxxxxxxxx>
> > Subject: RE: 3 phase pole pig (fwd), Richie's Site back up
> >
> > Richie's most excellent site.
> >
> > http://www.richieburnett.co.uk/dcresist.html
> >
> > Check the 6 pulse design.
> >
> > Jim Mora
> > Ojai, Ca.
> >
> >
> > -----Original Message-----
> > From: Tesla list [mailto:tesla@xxxxxxxxxx]
> > Sent: Thursday, November 01, 2007 3:33 PM
> > To: tesla@xxxxxxxxxx
> > Subject: Re: 3 phase pole pig (fwd)
> >
> >
> > ---------- Forwarded message ----------
> > Date: Thu, 1 Nov 2007 16:15:00 -0500
> > From: David Dean <deano@xxxxxxxxxxxxxxxx>
> > To: Tesla list <tesla@xxxxxxxxxx>
> > Subject: Re: 3 phase pole pig (fwd)
> >
> > On Thursday 01 November 2007 08:52:53 am you wrote:
> >> ---------- Forwarded message ----------
> >> Date: Thu, 01 Nov 2007 00:06:33 +0200
> >> From: Tomas Stankevic <Tomas.Stankevic@xxxxxxxx>
> >> To: Tesla list <tesla@xxxxxxxxxx>
> >> Subject: 3 phase pole pig
> >>
> >> Hi, I am going to get a 3 phase 25 kVA pole pig. Can I use all 3 phases
> >> to have maximum power? How could I do this?
> >>
> >> Tomas
> >
> > Hi Tomas
> >
> > Can you give some specs. on the transformer?
> >
> > I understand three phase is pretty common in Europe.   If you have a
> > three phase service it would be reasonably easy. You fed it three phase
> > in and rectify the three phase output and use it to power a DC coil.
> > Configuration would depend on how the transformer is wired internally.
> >
> > I remember seeing where someone had made three identical Tesla coils and
> > ran
> >
> > them in close proximity from a common three phase source, each on a
> > different
> > phase. The three toploads arced together to form a "Y". I seem to
> > remember someone else doing something similar with a solid state device.
> >
> > later
> > deano