Re: x-ray transformer questions

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

Original poster: "Bert Hickman" <bert.hickman-at-aquila-dot-net> 

Hi Jack,

It's too bad it's not a GE X-ray transformer, since NONE of GE's X-ray or 
medical transformers ever contained PCB's. Also, your X-ray repair tech 
appears to be correct - see the following thread for some more interesting 
information:
http://www.industrycommunity-dot-com/myforum/mike_gray/messages/41.html

Check the Pupman Tesla List archives for "PCB's" - you'll find a number of 
posts that mention some simple tests for PCB's (does the oil burn or does 
it float on water? If so it's not PCB's). The odds are fairly good that 
your transformer contains mineral oil.

Best regards,

-- Bert --
-- 
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Tesla list wrote:

>Original poster: "Jack Vandam" <snotoir7674g-at-mindspring-dot-com>
>Thanks for the info.  Unfortunately, I wouldn't be able to obtain the
>measurements you speak of without opening up the transformer.  Not knowing
>for sure whether or not PCBs are present, it's going to stay closed until I
>find out for sure.  However, I will save this info for future reference in
>the event I do open up the transformer.
>Jack
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Saturday, September 25, 2004 1:47 PM
>Subject: Re: x-ray transformer questions
>
>  > Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
>  >
>  >
>  > Most of the larger units, such as yours, have a 7.5 - 10 kVA core.
>Measure
>  > your core dimensions and I can give you a better estimate.  Core cross
>  > section is one of the most important factors with regard to the magnetic
>  > flux.
>  >
>  > The 7.5 - 10 kVA rating is approx 75% duty cycle but can be exceeded for
>  > short periods of time such as charging up large Marx bank caps, etc.
>  >
>  > If you plan to run it constant, they you would be wise to operate at 5-6
>kVA
>  > as a maximum.
>  >
>  > The reason the power levels are not specified is because different types
>of
>  > buck/boost reactors (external) were used with these xmfrs, so ratings
>depend
>  > on heat rise vs. time.  You could determine the proper rating by operating
>  > the xmfr in sec short circuit condition and carefully monitoring the core
>  > temp with a thermister.  Many modern multimeters have these probes.
>  >
>  > Core temp vs. time will give you a reasonable estimate of how much power
>you
>  > can operate at.  Core temp should not exceed 180 degrees F. (max) for most
>  > applications.  You can carefully dry off a section of core and wipe clean
>  > with a solvent.  Then, using conductive epoxy, attach your thermister.  Be
>  > sure to keep this conductive epoxy away from the HV coils.
>  >
>  > Keep the core temp below 175 degrees F. with long run times and you should
>  > be ok.
>  >
>  > This was our approach on a large X-ray xmfr we used to charge a 100 kV
>Marx
>  > bank.  It worked out to approx 12.5 kVA for short duty cycles less than
>25%.
>  >
>  > Be extremely care --- these things are killers.  We attached a large red
>  > rotating beacon to one side of the 220 to ground (120 VAC) so the beacon
>was
>  > on any time HV was on.  Use a relay so it will energize as soon as your
>  > control circuit applies any voltage to the primary of the xmfr.
>  >
>  > Dr. Resonance
>  >
>  >  >
>  >  > Tonight's questions concern a Westinghouse x-ray transformer.  There
>are
>  > two
>  >  > things I'm wondering about with this unit: its specs and input/ output
>  >  > information.
>  >  >
>  >  > Here's what's on the label:
>  >  > cycles 50/60
>  >  > wiring 3D 8939
>  >  > style 981928
>  >  > Volts AC, KVA, and Amps are all blank.
>  >  > Under the word "Westinghouse", there are the following tiny numbers:
>  > 36233-D
>  >  >
>  >  > Can anyone figure out the complete specs with this info?
>  >  >
>  >  > Now for the input connections:
>  >  > XFL, XFC, XFS, G, MA, A, AA
>  >  >
>  >  > Input hookup info?
>  >  >
>  >  > And, finally, there are two high voltage recessed terminals.  One has a
>  >  > single center conductor; the other side has three (their purpose?).
>The
>  >  > diameter of the sockets is 1.25".  I did manage to obtain some high
>  > voltage
>  >  > cable at one point, but the end diameters are too large.  I'm
>considering
>  >  > making new ends out of epoxy or if I could obtain the correct size
>cable
>  >  > economically, I would go with that.
>  >  >
>  >  > Dimensions are about 13.5x17x15 inches and it must weigh at least 250
>lbs
>  > I
>  >  > would guess.  Not sure what I'm going to use it for, but my purpose
>right
>  >  > now is to just find out about it and get it going, using an appropriate
>  >  > variac for current limiting of course.
>  >  >
>  >  > If anyone has any info on this or a similar unit, I would appreciate
>your
>  >  > sharing of it.
>  >  >
>  >  > Thanks,
>  >  > Jack
>  >  >
>  >  >
>  >  >
>  >
>  >
>
>.