X-Ray Transformer Construction Primary Coil Count

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Cameron Palte
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Real name: Cameron Palte

X-Ray Transformer Construction Primary Coil Count

Post by Cameron Palte »

Hello all,

Recently I have been researching into the theory used in transformer construction particularly how the voltage and current scale from the primary to the secondary (without inefficiencies) etc. I understand how for example if I have a 240v input that I want to increase to 72kV on the secondary I need a 300:1 coil ratio for the secondary to the primary. This means that at the same time the secondary will have 1/300 the current (again assuming no inefficiencies).

However, I have not been able to find anything on how many coils the primary needs. For example if I wanted a 300 to 1 ratio as described above the most cost-effective method would clearly be for the primary to have 1 turn and the secondary to have 300 turns. However, that is never the situation, the primary always has a respectable number of turns on the order of dozens from what I understand.

So my question is for someone looking to build an X-Ray Transformer type device submersed in oil with the same numbers (240v to 72kV and a 1:300 ratio) how would one go about determining the number of ratios the primary coil should have.

Thank you! Let me know if you need me to clarify anything.
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Rich Feldman
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Re: X-Ray Transformer Construction Primary Coil Count

Post by Rich Feldman »

Cameron, it sounds like you haven't been searching very hard, or need to work on your Internet searching skills. If finding an answer takes a dedicated hour, that doesn't mean the Internet way isn't working. It still beats the old way by a lot.

The minimum number of primary turns is determined by the core material and dimensions. Any given core has a maximum volts-per-turn value for 60 Hz sinusoids. The volts-per-turn number goes up in direct proportion to the operating frequency, and is slightly different for square waves. Keywords "saturation" and "flux swing" are relevant.

Here is one really good DIY transformer design tutorial: http://sound.westhost.com/xfmr.htm

If you have a healthy need to do lab work, use a Variac to drive some winding of another transformer. Measure the current as you sweep the voltage from 0 to twice the nominal voltage for that winding, or until the current is too much for the winding under test (whichever comes first).
All models are wrong; some models are useful. -- George Box
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Dennis P Brown
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Re: X-Ray Transformer Construction Primary Coil Count

Post by Dennis P Brown »

Found an interesting site on how to build a high current, high voltage flyback transformer - nice pic's and instruction. This isn't a toy and if built, carries lethal voltage/currents so understanding how to safely handle such a dangerous transformer is solely your responsibility.

Here is the link: http://adammunich.com/fryback-transformer/

Again, while simple this is a very high power transformer that can be deadly.
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Richard Hull
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Re: X-Ray Transformer Construction Primary Coil Count

Post by Richard Hull »

I looked at the site. Claims are made without any backup data. In the end, it is stated that 8kv and the current ..."a lot"!

In my tesla days, on one of my video tapes, We drew 2 foot long arcs from a 60 hz, 1kva, 12kv transformer in the vertical. 12kv will barely jump 1 inch! In the vertical you have ions a plenty and heat rising all aiding to increase spark length far beyond the real gap in the horizontal. Please do not believe that 20kv can ever jump more than a fixed gap 1.5 inch arc in normal cold air. such big arcs are achieved by moving the gap from 1" to much larger widths in concert with high currents heating the air. It is the only reason a jacobs ladder works.

Real measurements of a system under load are rarely given with images, due to a failure on the part of the person making such claims having the instrumentation or the know-how to measure, using a sufficient and proper load in the high voltage high current, regime. Lots of images and bold claims with no instruments in sight.

As shown, this would certainly be a good belt sprayer for a VDG. Perhaps a bit much for same. A good belt sprayer could be fashioned from and near microscopic flyback as even a giant sphered VDG could not fully utilize the current supplied by even a simple rectified, neon transformer.

The issue for a fusor supply is can such a flyback supply a suitable voltage multiplied steady current to a fusor. No one has done it yet.

It is good that folks are looking at high frequency supplies for fusor work as it might be the only way for some to achieve fusion, but it is an up hill battle for most.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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