RE: Dental X-ray transformer

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

Original poster: "Loudner, Godfrey by way of Terry Fritz <twftesla-at-qwest-dot-net>" <gloudner-at-SINTE.EDU>

Hello Mark

For experimenting with x-rays, a complete unit consisting of a tubehead and
control panel would be a steal for $150. But I suspect that its the
transformer in the tubehead that your after. Because its from the 1960's,
the transformer is most likely to operate at 60Hz with an input about 80 to
120 volts, and an output about 56kVp to 90kVp at 10MA to 15MA. A few of the
older units have small transformers which operate at around 20kHz with
output of 10kVp to 15kVp, but the voltage is boosted to about 70kVp using
diodes and capacitors in a voltage multiplier circuit. In this situation,
you would need the control box which supplies the 20kHz. These voltages are
too high and the currents to small to supply a tesla coil without taking
extraordinary preparations. Even if you reduced the output to say 15kVp, the
current might drop to only a few MA. To get at the transformer, you would
have to open the tubehead. The oil inside might be PCBs, and there is also
the danger of coming into contact with very toxic beryllium salts on the
x-ray tube window which will ruin you health if you ingest them. Unless you
are really knowledgeable, you should not open a tubehead. 

Of course, the unit might only be the transformer itself, which saves you
from the nasty work of opening a tubehead. I have seen such exposed
transformers on ebay sell for about $170. I have three identical 60Hz
General Electric tubeheads of the older type which I got for $5 from a
junkyard. I will not open the tubeheads until I am sure that they contain no
PCBs. I suspect that the winners thought they had a super transformer for
tesla work---I know that they were disappointed. For tesla work, I would not
waste my money on such a transformer. If you are willing to spend $150, you
should be able to find a good HV transformer. I would not count on ebay to
find a good transformer, except for NSTs.  The bidding get too high, and
there is also the shipping charges.  

Godfrey Loudner 

> -----Original Message-----
> From:	Tesla list [SMTP:tesla-at-pupman-dot-com]
> Sent:	Sunday, May 27, 2001 10:22 PM
> To:	tesla-at-pupman-dot-com
> Subject:	Dental X-ray transformer
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <A123X-at-aol-dot-com>
> 
> Would $150 be too much for a 1960's dental X-ray unit? I might be able to 
> find out more about it. 
> 
> Mark  
>