Altering a Neon Transformer Grounding

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Logan Holler
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Altering a Neon Transformer Grounding

Post by Logan Holler »

Hello all! Its been awhile, I come with a question about our NST (Allanson Neon Transformer 1530BPX120R) and a potential modification. As it stands, we can only rectify half of wave only giving us an output of 7.5 kV since we cannot go full peak to peak, as expected. Our lead electrician had suggested the idea of disconnecting the Earth grounding and allowing the case to become hot, but hopefully letting us capture as much of the 15 kV as can be provided by the NST. Obviously, we would then put the case in a HV safe enclosure if we were to make the case hot.

I hunted around the forums for a few hours and I found Richards paper to Electric Spacecraft Journal which seemed to mention something similar (or I maybe reading it wrong and he did this exact idea) in the 'Further thoughts on the application of neon transformers' section wherein he made the case hot as well. In that paper Richard had mentioned that the insulator would become physically hot and had the potential to be a fire hazard which would mean some form of cooling would most likely need to be investigated with it. While I know it is generally not advised to tamper with the pre-built transformers I was wondering if anyone had done so and posted about it somewhere where I missed it. Or any other thoughts regarding this are accepted (including telling us its just a bad idea to try).

Thanks!
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Richard Hull
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Re: Altering a Neon Transformer Grounding

Post by Richard Hull »

You could certainly do that. The second person to ever do fusion a month after me back in 1999 was my fellow engineer friend in Texas, Scott Little. Scott did this 15kv neon trick with a 60ma transformer and backed it with a 20ufd 25,000 volt capacitor. YIKES!! He hit the full 21kv to his fusor and did fusion, detected with his 3He neutron system. The capacitor was the largest item in his system.

Nothing will get physically hot. When I say hot it means not safe/high voltage. you will be forced to ground one knob on the transformer. Hopefully the insulation on the other knob which is normally exposed to only 7.5kv will hold as well as the core iron to the winding top that is all of a sudden at 15kv and not 7.5kv. The metal case of the transformer will be at 7,500 volts. You will be forced to only half wave rectify the voltage, of course.

I suggest you ground the knob at the end of the transformer where the 120 volt goes it to avoid having 15,000 volts near the line/neutral connection.

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
Logan Holler
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Re: Altering a Neon Transformer Grounding

Post by Logan Holler »

Thank you Richard!

I sent this forward and we will be talking about it next week as a possibility! If I may ask, when you mentioned the fire concerns, I am thinking that is a product of overloading the one half of the system? While that is my main concern, I just want to make sure I am not forgetting something else that may ignite. I should mention that our transformer is filled entirely with a quartz/epoxy slurry so we wont be able to get in and modify anything inside the case (either for improvements or safety).

Once again, many thanks!
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Richard Hull
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Re: Altering a Neon Transformer Grounding

Post by Richard Hull »

Any possible fire hazard would be related to external arcing if case arcs to a combustible material or internal arcing setting the asphalt tar insulation within the case on fire or softening it to become a liquid running out of the case to catch fire. Highly unlikely as you would not be getting much output voltage with internal or external arcing.

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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Dennis P Brown
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Re: Altering a Neon Transformer Grounding

Post by Dennis P Brown »

As I understand previous posts on this subject, the rather big concern for any NST x-former is the problem of continuous current or lack there of - the reason the person used a huge cap was a NST can not sustain continuous high current due to its design. A NST has a high start up current then saturates and the current falls to a rather low value. Or at least as I recall so it isn't useful except for holding a plasma for a demo fusor.
Rex Allers
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Re: Altering a Neon Transformer Grounding

Post by Rex Allers »

Logan,

I'm not sure what you are planning to try will work with this neon transformer. I searched for 1530BPX120R and found this seller's link...
https://ballastshop.com/1530bpx120-alla ... b-addition

Is that the one you have? Does it have a LED indicator and some kind of reset switch?

Size-wise it looks like a tradition transformer (not a switcher supply) but the listing talks about fault sensing in the unit.
  • There is a secondary circuit ground fault protection (SGFP) circuit built in to avoid arc to ground
  • The is a an LED display making setting and diagnostics easier
  • Dimensions are same as the UL506 models eliminating need to change casings, raceways or existing signs
  • Has a 30-minute by-pass button switch which works like the UL506 models
  • There are 3 automatic resets designed to eliminate nuisance tripping for more continuous service
If there is a traditional transformer inside (is it heavy?) and you are able to find a way to lift the center connection, these monitors may need to be disabled too. I don't know how they are implemented so have no idea how that would be accomplished.

The old-school simple neon transformers with no protective internal circuits are getting very hard to find.

-----
Dennis,

I think your description of neon transformer behavior is a bit garbled.

They can provide their rated output voltage at no load (zero or tiny current). As the load increases (effective resistance of the load drops) the transformer will eventually be able to make the rated current but at that point the output voltage will have sagged quite a bit below the rated voltage.

It behaves a bit like a stiff voltage source with a large value resistor in series to the output terminals.

Richard has covered all this in great detail in his FAQs.
Rex Allers
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Dennis P Brown
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Re: Altering a Neon Transformer Grounding

Post by Dennis P Brown »

Certainly forgetting details since I was drawing from past memory and don't bother with those boat anchors except for diode testing; bottom-line is correct, they are not suitable for a fusor even if the center tap is removed.
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Richard Hull
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Re: Altering a Neon Transformer Grounding

Post by Richard Hull »

The giant capacitor used by Scott allowed for sag on the neon and holding the voltage up during one half cycle at higher than normal load current. almost no one here has such a capacitor or is likely to obtain one. Heroics with neon transformers like Scott's example is just ludicrous. Only he could do it as he had the stuff on hand. and that capacitor stored instantly lethal energies. Scott knew this and acted accordingly. One week after he did fusion his system was dismantled and was never reassembled. He needed his turbo and vacuum system for normal work he had sidelined.

There is no way possible to lift the center tap on a standard old heavy, iron cored neon transformer due to the solid chunk of asphalted/tar filled steel case. Such an effort is doomed from the start for any number of viable reasons.

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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