RE: What do I do ?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Rich & DJ" <rdj@xxxxxxxxxxxx>

Thanks Gerry
I think I am getting to workable solution, my little cheap DVM is
reading a voltage that would be expected then as I raise it the gap
fires, at that point the voltage drops dramatically. That is why I
reported the 140v when it s/b 220 to 240. Would I be better off with a
standard panel meter than the DVM when try to read the input at the
transformer. I have a complex voltage supply system and can feed the
transformer from O to approx 300v.I am using a 0 to 140 Variac ,
120/208/277 , step up trans , then the ballast, the HV trans has
208/220/240 taps. It sounds like a mess but my 240 Variac is tied up on
something else.

Rich

Subject: Re: What do I do?

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Rich,

I would suspect so.  The problem might be if you cut the gap too
wide, it would be hard to close it again.  I personally would try to
play with a shorted secondary first to see if your current levels can
be obtain.  You might experiment with the number of turns on the
secondary being shorted. I would not, however, take turns off of the
primary as this could cause the core to saturate.  In this
application, volts per turn and core area are the major factors
determining where saturation occurs.

Gerry


>Original poster: "Rich & DJ" <rdj@xxxxxxxxxxxx>
>
>Can a gap be added with a saw??? This is an old Jefferson and does not
>have an EI core and no visible shunts.
>
>Rich
>
>Subject: Re: What do I do ?
>
>Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
>
>I suspect the problem is the NST with primary only.  The inductance
>would be high with little current going thru it if you removed the
>secondary and didn't add any gap to the EI core.  The current allowed
>would be the same as the current thru a working NST of the same
>design with the secondary opened (probably not much current).  When
>you added a secondary using 7 turns of 10 gauage (presumably
>shorted), this allowed current to flow thru the primary.
>
>Gerry R
>
> >Original poster: "Rich & DJ" <rdj@xxxxxxxxxxxx>
> >
> >I am trying to get a transformer and ballast set up with just a
> >spark gap for now. It is multi gap copper tube set up, 8 tubes
> >total, 5 tubes in use @ .050 each .200 gap.
> >The first ballast try was with a roll of 12 ga w/steel core and a
> >NST transformer core with just the primary, when I ramped up the
> >supply voltage it would barely fire when I got up to 95% on the
> >voltage at the transformer input. I added 7 turns of 10ga for a
> >secondary on the NST core, now I get good sparks at 60% voltage.
> >Can any one tell me why ?
> >I am using the roll of wire and NST core to limit my transformer to
> >1.95Kva max. It is all trial and error at this end , should I add
> >more turns on the NST secondary until I get null spot.
> >  I am getting actual  8 amp at the input of the transformer at 140v
> > , max s/b 8 amp at 240v.
> >I have a volt and amp meter at the transformer input.
> >I think I would be better off with more volts and less amps or ????.
> >
> >Rich , from the middle of Missouri
> >
> >
>
>