RE: X-ray Power Supplies (fwd)

[<sroys@xxxxxxxxxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 24 Sep 2004 14:32:22 -0500
From: Carl Litton <Carl_Litton@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: RE: X-ray Power Supplies (fwd)

Thank you, Peter.  (and to others responding) Great site and pictures.
OK on the ballast; I have MOT's stacked up like cordwood around here.
Short the primary leads to each other and put the secondary in series
with the HV output, no?


We, of course, had to open up the behemoth as soon as it was off of the
truck.  Lots of oil, but no discernable capacitor?


HUGE iron-core toriodal transformer at the bottom - incredible and in
perfect appearing condition (new looking actually).  A second medium
sized transformer (or inductor or something) just under the lid.  8 rows
of 10 rectifying diodes (presumably given the fact that output can also
be read on DC scale).  No capacitor though?



Grime removed from spec plate to reveal:

Bennett X-ray Corp. Model T-835
Mfd.  December 1976
Volts:  220
Max rating m.a.:  330
KVP:  125
****Amp MOM:  2
****Amp L.T.  132


****???uncertain meaning


7 lug terminals on top (of which only the first 3 are understood -
primary input).  They are labeled:

P,   PC,  G,   FC,   FF,   FB,   M1,   M2 



*****I put 1.0 +/- 0.5 VAC across the primary and read both 492 VAC and
858 VDC on the secondary!  *****  Wow.


This is truly a non-trivial find.



Carl Litton
901-374-5747

-----Original Message-----
From: High Voltage list [mailto:hvlist@xxxxxxxxxx] 
Sent: Thursday, September 23, 2004 9:34 PM
To: hvlist
Subject: Re: X-ray Power Supplies (fwd)

Original poster: <sroys@xxxxxxxxxxxxxxxxx>



---------- Forwarded message ----------
Date: Fri, 24 Sep 2004 08:59:20 +0800
From: Peter Terren <pterren1@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: X-ray Power Supplies (fwd)

X-ray supplies are a lot of fun. They need to be ballasted and I use a 
single MOT on my mobile x-ray transformer which uses only about 17kv AC 
transformer with a dual voltage doubler to get 100kV. Dental x-ray 
transformers are great for a small supply at 60kv in a tiny package and
with 
a doubler can give a spark longer than the transformer.  I also have a
125kV 
head which I have yet to put in oil again to get it going.
Components such as diodes, caps and resistors all present their own 
challenges. They are extra lethal, particularly with the capacitor.

Pics on my site
Peter (Tesla Downunder)
http://tesladownunder.iinet.net.au/Other_HV_stuff.htm#100kV


> From: Carl Litton <Carl_Litton@xxxxxxxxxx>
> We just acquired a donation today of what I am told by the owner of
the
> x-ray repair shop is the power supply to an old 'Frankenstein' era
x-ray
> machine containing a large transformer and a capacitor that reportedly
> hold a very large charge for a couple of days -- all covered in oil.
>
> It is an olive drab steel box 2' cubic weighing a little less than
> 200lbs. with 2 large holes in the top looking down into some clear oil
> and submerged metal.  Large cables come out of the top.  220 VAC input
> to primary and spec. plate reads that secondary output is 120 KVP
> (assuming that to be Kilovolts Peak) at a current of 330 m.a.
>
> Now, I need to know about such devices as this is seriously beyond my
> little (relatively) 39 lb. 15 kV NST's  and appears that it could
> actually be dangerous ;).
>
> Anyone with experience on hi-powered x-ray transformers  - would you
> please direct us to any articles or information on care and feeding of
> such a device and caveats about any salient differences one encounters
> with this type of power supply compared to the usual MOTs, NSTs,
> ignition coils, etc.
>
> [I'm sure more folks will add their thoughts, but XRay transformers
are DC
> devices and will kill you very quickly.  100kVDC is nothing to be
> careless with - your first mistake could very well be your last.  As
> Richard hull would suggest, make sure you always have a friend there
with
> a long 2x4 to push your body off the terminals and put the fires out
(with
> a non-H2O based fire extinguisher!)  SRR]
>
> Carl Litton
> Hilton Hotels Corporation
> 901-374-5747