Re: X-Ray Machine Transformer

To: tesla-at-pupman-dot-com
Subject: Re: X-Ray Machine Transformer
From: "David Dean" <deano-at-corridor-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sat, 01 May 1999 23:30:05 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme
Don't let them junk it!
The rectifiers are great. I bought one out of an industrial X-Ray machine about
three years ago- didn't know what it was- thought it might be something I could
use to rectify my A/C welder so as to make better use of DC rods but...It took
130 volts just to forward bias the thing so it sat on a shelf 'till last year
when I thought it would be useful for a DC T.C. supply. Now after I took it
apart I find it has a string of 27 diodes in series. They are about the same as
microwave oven diodes as far as I can tell, but the PIV rating is probably
higher. The diodes were connected in series without any equalization resistors
or capacitors at all. Connection was by welding, not solder. The diodes were
then folded up into a compact bunch and slid into a brittle black plastic tube
of some kind. The tubes had metal end caps that snapped into holders like the
cartridge type fuses use. The bridge was inside a tank which was filled with
oil. I have divided the string of 27 into 4 strings of 6 (with 3 left over to
play with) to make a bridge to use with my pole pig. (Hopefully someday I will
get time to finish the project I started last June, a 12" x 48" sec. DC powered
T.C.)
The capacitors in that thing may be usable as T.C. pulse caps in their own
right- some caps sold on the NET for that purpose are in fact X-ray machine
caps. At any rate the voltage rating would be high enough.
As to the transformer itself, the voltage is a bit high but you could
always use
a variac to bring it into range.
If you wanted to build a DC T. C. just stick a large variac on the AC input, or
a step down transformer and you have a readymade power supply. The only problem
I can see with that is the filter caps might be of too small a value at say
20kV
DC. But if you had a way to insure the voltage never got too high you might be
able to swap the caps for some with a higher capacity and lower voltage rating
and then use the X-ray caps in the T.C. pri circuit if their value is close
enough.
Anyway, take it home. If you don't use it I am sure someone else would love to
have it.
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Saturday, May 01, 1999 8:05 AM
Subject: X-Ray Machine Transformer


>Original Poster: David Trimmell <davidt-at-pond-dot-net>
>
>I have a question. I could get an old X-Ray machine form my work, if I
>wanted to lug it home. It is a Siemens, 125kV, and the dial goes up to 500
>mA, full size medical machine. Does anyone here have any experience with
>medical x-ray equipment? The transformer is, of course, what really
>interests me, its probably about 350 pounds, rated at 220 primary, 125 kV
>sec.  It is really quite bulky compared to the new high tech units we have
>here, dial knobs and all on the control unit, compared to digital controls
>on the new ones. I keep the computers going here, and do not know anything
>about this type of equipment. Is there anyway to modify the transformer to
>put out less voltage? I suppose it has a nice fullwave bridge to get the DC
>output for the Tube. Would it have any potential for T-coil service?
>Potentially valuable parts? Should I just let them junk it?
>
>Regards,
>
>David Trimmell
>