I believe there is an air-gap in the core that limits the maximum flux (amp-turns) of the transformer. Be aware that bombarding is done at much higher current than the typical output of a neon-sign transformer.
On Friday, November 29, 2024 at 8:42:32 PM UTC-8 Mark Moulding wrote: > Well, Terry, that was very interesting. I just went out to the shop and > measured the resistance of the secondary of my neon sign transformer to > ground, and sure enough it was definitely non-infinite (about 50k from one > side, and greater than the 2M maximum of my cheap garage DVM on the > other). I personally was still using it safely, because I clamped one side > of the secondary directly to the workpiece, and the other I held at the end > of a 14" plastic rod - but still... > > What do you mean by "shunt limited"? I always believed that the current > limiting was by virtue of the inductive impedance of the many turns in the > secondary - basically the same as a fluorescent lamp ballast. Is there > some other mechanism at work? > > On Thursday, November 28, 2024 at 6:56:37 PM UTC-8 Mac Doktor wrote: > >> >> On Nov 26, 2024, at 3:15 PM, Mark Moulding <[email protected]> wrote: >> >> Those transformers are dangerous as hell, because one side of them is >> ground (plus nearly a full amp or so available current - 1 kW, right?) - >> super easy to get a path through YOU to ground. I've done "fractal art" >> (nothing to do with actual fractals, of course), but I used a neon sign >> transformer - isolated, and only around 15 mA of current - and switched it >> with a momentary foot pedal. It would still have been an exceedingly bad >> day to get across it, but I probably would have survived. I was extremely >> careful... >> >> >> For those who aren't aware, neon sign transformers are current limited >> using shunts. Also, the secondary is center tapped to ground so the >> potential from one wire to ground is only half that of the full secondary. >> Or something like that. 8D >> >> >> Terry Bowman, KA4HJH >> "The Mac Doctor" >> >> https://www.astarcloseup.com >> >> “...the book said something astonishing, a very big thought. The stars, >> it said, were suns but very far away. The Sun was a star but close >> up.”—Carl Sagan, "The Backbone Of Night", *Cosmos*, 1980 >> >> >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/6519584e-5071-4681-9c98-a1543a9b33c9n%40googlegroups.com.
