RE: X-Ray Transformer HV Power Supply

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Thomson by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dave-at-volantis-dot-org>

I noticed on my X-ray transformer that the tube seems to be built right into
the transformer case.  I was looking for a place to connect the high voltage
output wire and found something that warns of X-rays and some kind of
emission plate instead.  I need to do more investigation before I'll turn it
on.

Dave

 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Monday, May 05, 2003 8:38 PM
 > To: tesla-at-pupman-dot-com
 > Subject: Re: X-Ray Transformer HV Power Supply
 >
 >
 > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
 > <dhmccauley-at-spacecatlighting-dot-com>
 >
 >
 > Thanks for the great info.  This transformer is coming right out
 > of a dental
 > x-ray head and isn't nearly as heavy as your 1000 lbs behometh!
 > The whole assembly is about 50 lbs so the transformer probably isn't that
 > big.  I'm not sure how useful this transformer will be (maybe run
 > only 1-5mA
 > continuous?), but it will be
 > fun to take this thing apart and experiment a bit with the transformer.
 >
 > Thanks
 >
 > The Captain
 >
 >
 >  > Captain,
 >  >
 >  > I have a 140 kVP, 500 mA x-ray transformer that tips the scales at
 >  > nearly 1000 lbs. and I am just using it to drive a wicked Jacob's lad-
 >  > der. It had the rectifier assembly inside it when I got it but
 > the recti-
 >  > fiers quickly burnt out when I started shorting the outputs, even with
 >  > the input to it well ballasted. I finally had to pull the core out the
 > tank
 >  > and take out the rectifiers and just use it as an AC HV supply. The
 >  > diodes that come in these x-ray trannies are very physically small
 >  > for the > 100 kV at several hundred mAs that they can put out. Of
 >  > course they are designed to be submerged in oil during operation
 >  > and for very low duty cycle (usually < 1 second for the x-ray expo-
 >  > sure). It seems to me that you would almost have to have your rec-
 >  > tifier assembly submerged in oil just like the transformer but that
 >  > it would require a considerably more robust rectifier for continuous
 >  > power supply/ and or capacitor charge duty. I have 11 of those 5 kV,
 >  > 2 amp hockey puck style diodes that I am currently using (all of them)
 >  > as  rectifier for my (2) seriesed 7200 volt PTs that I use to charge my
 >  > (2) 10 kV, 100 uF coin shrinker/can crusher caps. I think this style
 >  > of diode would probably work for rectifying an x-ray trannie's output
 >  > if you had enough of them (like at least 40 per leg) and they were al-
 >  > so submerged in oil.
 >  >
 >  > One thing you need to be well aware of when dealing with x-ray trans-
 >  > formers is that their output voltage is very high and has
 > enough current
 >  > to be EXTERMELY DANGEROUS. Mine will easily jump the ~ 8" gap
 >  > at the nearest approach of the sparking rails of my Jacob's ladder and
 >  > as I run the variac up, it begins corona hissing like 100 angry rattle
 >  > snakes before the 8" gap finally breaks down. This hiss sounds quite
 >  > wicked and could also be compared to the sound of frying bacon. I can
 >  > actually feel the "electric wind" in my face or on the back of my hand
 >  > through the grounded chicken wire cage around it when the voltage is
 >  > turned up to the point just before spark breakdown between the Jacob's
 >  > ladder rails (probably at least 2 ft. away from the nearest HV
 > terminal,
 >  > with the grounded chicken wire cage between me and the HV terminal)
 >  > This is certainly not for your beginner HV experimanter ;^0
 >  >
 >  > Be safe,
 >  > David Rieben
 >  >
 >  >
 >  >
 >  >
 >  >
 >