Hi Eric, yes, a fuse makes perfect sense.
Jogi's Rohrenbude has also some HV regulated supplies on his site, most are build with semiconductors and are shortcircuit protected.
In a perfect world where I have endless time I would certainly build such a power supply. But for the moment I am looking for an easy way to safely get what I want, and those PTC fuses Michel mentioned are quite nice for that purpose I guess. So I hope you don't get this the wrong way: I know those circuits at Jogi's website are gold, but I do not have so much time, and I would like to focus on Nixie tubes and their building. (And, let's face it, I am not going to short my power supply for longer than a second or so by accident anyway)
Thanks, Jens
eric -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of jb-electronics Sent: donderdag 10 mei 2012 12:14 To: [email protected] Subject: [neonixie-l] Linear HVPS with a Variac Hi folks, for my Nixie tube making I need a power supply with a little more juice than the 300V @ 10mA Traco module I have been using until now. This is what I came up with: I have a nice 400W variac, so if I connect that to a transformer back-to-back circuitry (serving as a voltage amplification as well as galvanic seperation), this - after rectification and a smoothing cap, of course - gives me an adjustable voltage of U_out_max = SQRT(2) x 230V x (15 : 9) = 542V DC . Using some kind of gear on the variac knob will allow a reasonably accurate adjustment of the output voltage. For the back to back transformers I would like to use 16VA versions, supplying me with I_max = 16 VA / 542 V x SQRT(2) = 42 mA . Any mistakes so far? Anyway, I was wondering what happens if you short the output of this setup for a short time (< 10 seconds). The transformers I would like to use are NOT short-circuit-protected. But I suppose for such a short time this is not critical, is it? I will include a voltmeter and amperemeter, and if the amperemeter measures a current above a specified value (let's say 40mA) it will shut down the output voltage using a relais. This is not a perfect over-current protection, but the easiest one I can think of at these voltages. This whole setup is still in the planning, but it is the simplest design I could imagine. Is there any major flaw in my design that I did not think of? Thanks for your input, it is much appreciated. Jens -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
-- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
