Re: High Voltage Transformer
Posted by Wes Martin on 3/27/2007, 8:20 pm, in reply to "Re: High Voltage Transformer"
Yeah, I had a sneaky suspicion that the rating was in peak volts. So in fact, my 70kv tranny is probably closer to 49.9kv(rms) at rated load. Makes sense. So.. I suspect that with no load, the peak voltage on the secondary could potentially rise to something much higher! Of course this would probably cause internal shorting inside the tranny, so I should probably not do this. Well, OK I admit. I did. And left it running for a few minutes, albeit with only about 80vac on the primary. I had some rather long strikes from the thing! But never any internal shorting that could be detected (it is submerged in Voltesso 35, in a glass one-piece 1945 fish aquarium that allows me to see every part of the tranny). I wonder if full 120v with no load would ruin it? That Voltesso is good for 35kv/mm; I almost want to try it! ;-). Perhaps I should leave well enough alone. i did have some fun with it and a 12v battery, though! I pulsed some DC through the primary and got some fantastic lighting from the thing! I better cut that out too! ;-)|
Thanks for the information, Bert! These are serious transformers, and I want to do what I can to ensure I am knowledgeable about them (so as not to ruin them, or myself)! Cheers, -Wes.
: --Previous Message--
: One last question for anyone who might know about these 70kv / 100kv
: transformers from x-ray units.. This 70kv unit I have here; does this
: thing actually put out 70kv, or is that the rating after the diode
: rectifier?? I have no way of directly measuring these insanely high
: voltages, but with 60vac measured directly across the primary connections
: (using a resistive ballast) I can draw an arc about three inches long.
: Theoretically, that would be approximately 35kv (assuming 120vac gives the
: full 70kv) - and assuming of course the physical winding ratio is really
: 583:1!! Are these things really capable of 70kv (or 100kv)? Does there
: exist a xfrmr that really put out 100kv?? I seem to be getting mixed
: messages on the internet about this. Thanks again! -Wes.
: Hi Wes,
: Unlike most transformers (that are rated in RMS volts), X-ray transformers
: are rated for peak volts at a given current load. This is because the peak
: voltage rating reflects the maximum energy of the x-rays that can be
: created (which, in turn, determines penetrating power of the resulting
: The peak output voltage is independent of whether the output is rectified
: or filtered (unless a voltage doubling circuit is used). Rectification
: (with no capacitive filtering) will improve the duty cycle and thus the
: total x-ray power available. Adding a filter capacitor will reduce the
: "spread" between maximum and minimum x-ray energies, but again
: will not increase peak voltage.
: The distance an arc will jump is really not a very good measure of
: voltage, since the distance you can stretch an arc is strongly dependent
: on the amount of available current. Heck, you can even stretch a high
: current low voltage welding arc for an inch or two.
: The distance that a spark will initially jump between identical spheres is
: a considerably more accurate way to roughly measure peak output voltage.
: Here's a table that you may find useful:
: Good luck and please remember to PLAY SAFELY - X-ray transformers can be
: VERY nasty!