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RE: Re-configuring X-Ray Transformers



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

Hi Jack

Allen did a similar project at http://allencoilpage.home.att-dot-net . The
transformer should be clamped to a frame that is welded to the lid of the
tank. When you hoist out the transformer, the transformer can be unclamped
from the frame. It is best to hoist the transformer enough to allow for the
removal of the oil. Then lower the transformer back into the tank so that
more oil can drain from the windings. I allow one week for residual oil to
drain, and the process is aided by tilting the tank with blocks in a variety
of locations during the week. Now you won't have an oily mess on your hands.
Store the oil in absolutely clean, airtight 5 gallon containers. 

Now you will encounter a serious problem! At the bottom of each HV coil is a
thin lead. One lead is connected to the ground terminal on top of the tank.
The other lead is connected to the MA terminal on top the tank. A little
spark gap with the tank should be attached to the MA terminal. A milliampere
metering outfit in the control panel is connected across the ground and MA
terminal. Otherwise, your transformer is center grounded to the tank. There
is no super stand off insulation between the bottom of the HV windings and
the primary or core. If you to operate the two HV windings in parallel, you
are bound to have arcing to the primary or core. I cannot recommend that you
operate the transformer with the HV windings in parallel. You will have to
operate the HV windings in series by connecting the bottom leads together.
X-ray transformers are just not designed to have the bottom of the HV
windings floating high above the tank. 

The above must be tempered with the statement that if you wind the HV coils
down to 15kV to 25kV, that just might be low enough for the bottom
insulation to hold up. But what I have seen in my three x-ray transformers
does not encourage me enough to say go for 15kV to 25kV. 

Godfrey Loudner        

   


> -----Original Message-----
> From:	Tesla list [SMTP:tesla-at-pupman-dot-com]
> Sent:	Sunday, January 27, 2002 1:39 PM
> To:	tesla-at-pupman-dot-com
> Subject:	Re-configuring X-Ray Transformers
> 
> Original poster: "Jack King by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <speakernut-at-yahoo-dot-com>
> 
> Greetings,
> 
> Being the proud recipient of a few large x-ray trannys
> and controllers, I am desirous of converting them
> downward in output voltage for practical use. I've
> read threads of re-winding and so on, but nothin to do
> with what I propose specifically...Any of you tried
> this?
> 
> Anyway, I'm figgerin' on hoisting "Bertha" (125 KV -at-
> appx 500 ma) out of her oil bathtub, removing the
> diodes, hv relays and other "unneccessary" wares.
> Next, I plan to REMOVE somewhere around 60% of each
> side of her secondary, lift the midpoint connection,
> then paralell the two secondary windings, in phase.
> 
> I'm shootin for somethin between 15-25 KV -at- about an
> amp output with about 30% duty cycle. At least one of
> them will be used as a bombarding transformer for my
> neon plant.
> 
> As for the control cabinet: well I'm thinking of
> reworking that too, Keeping the large autotransformer,
> and then ADDING a second autotrans, modified as a
> series reactor...The autotransformers look to be made
> of decent core material and are an easilly accessible
> square core design (thank you Shimada), Question: on
> this second inductor, do I want to "break" the core?
> or 
> not?....I suppose it all depends on the "L" value of
> the inductors and a few other formulas I should review
> in the ARRL handbook.
> 
> Assistance and COmments Please:
> 
> THANK YOU
> 
> Jack King
> 
> NeoNut
> 
>