RE: [TCML] BPS Testing

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

Hi Bart,

As if things weren't complex, chaotic, and muddy enough, one further thing to ponder is whether the gap breakdown voltage does in fact remain consistent from bang to bang.  I have often wondered if in a static gap, if one bang closely follows another, if the likely greater concentration of ions (really not sure of their persistence) or just hot gasses or O3/NOx may affect and lower the subsequent bang's breakdown voltage. It's something that I can do with my scope and fiber optic probe, but just gotta get a round tuit...

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of bartb
> Sent: Wednesday, March 12, 2008 9:35 PM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] BPS Testing
>
> Hi Gary,
>
> Lau, Gary wrote:
> > As I had mentioned, I had measured the NST's short circuit current and found it
> to be not far from the faceplate rating of 60mA (I don't recall the exact number).
> Low voltage side (primary?) short circuit current???  I don't think that winding
> resistance measurements would indicate much.  I have not tried measuring the
> open-circuit voltage as I have no reason to suspect that it differs significantly from
> the faceplate rating.
> >
> Well, then it's certainly a 60mA unit. I like to measure my NST's data
> as much as possible to know what I'm working with, especially for these
> type of situations. Winding resistance does tell us impedance
> information, although it doesn't change a lot from the face place
> equated impedance (but a little). Gerry Reynolds helped iron out the NST
> impedance with Javatc allowing users to measure winding resistances
> (which almost everyone can easily do) and helps get just a little closer
> to reality.
>
> Today I looked at the nearest break to break occurrence with my 15/60
> test. The break occurred 1.1ms after the quench of the first break. This
> would require a 400mA continuous charge to get back up to the arc
> voltage in order to break 1.1ms later. That just seems much to ask from
> an NST and I'm not sure ferro resonance will do that (maybe). I know
> ferro resonance causes extreme voltages in cables and equipment, but
> there is usually a good reason for it (it's just not that easy to find
> the reason and that's where it gets difficult). Transformer saturation
> is one of those situations that can cause it.
>
> I also looked at the entire 12.7 second measurement data today and
> counted number of "soon after" breaks. I don't have the info in front of
> me, but it was something like 83 occurrences. If I removed those 83 from
> the total 998 breaks during that period, bps equated to 72. There is
> something here that's real. It shows that charge time of caps up to the
> firing voltage is as it should be, but there are these series of breaks
> that occur soon after for some reason (either ferro resonance or
> possibly a partial discharge and then re-ignition). It has to be one of
> those two reasons.
>
> > Looking forward to your 140VAC measurements!
> >
> I'm looking forward to it also.
>
> Take care,
> Bart

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla