Hacking NST to get Fusor Power Supply

[Jack Williams]

So I'm curious. My impression is that a 15kv@60mA neon sign transformer can't just be hooked up to a 3 stage voltage multiplier to get the ~30kv@20mA, but why is that? Wouldn't this be a relatively simple way to get easily detectable fusion? Even with lower current or voltage models you could hook up several transformers in parallel and/or add more stages to get fusion power. I have no experience in fusors so please correct me if I am wrong.

[Benjamin Walsh]

A few things. Normally I wouldn't respond to something like this, but it might spare you some flak from other members of the forum who are tired of posts like this. Not that I blame them....

1. Please use your real name on this site. Thats posted pretty much everywhere. You can go into your settings to change your username. How to do this is in a FAQ or guide somewhere.

2. Speaking of FAQs: they contain the answer to your question, along with tons of other very useful information. Please check them out. The answer to this specifically is in the Voltage Multiplier FAQ by Richard Hull, and is probably mentioned in several others. Very handy.

3. Please post in the "Please Introduce Yourself" section.

I think that's it. Good luck in any fusion efforts.

[Rich Feldman]

Welcome, Joe.
It's all in the FAQs, or findable with a few hours of browsing.

First of all:
if it's a NST then the 15,000 volt number on the nameplate is the open circuit voltage,
and the 60 mA number is the short circuit current. You can't get anywhere near both at the same time.

Second: the midpoint of secondary winding is tied to the core and to the case. Primary and secondary insulation are designed accordingly.

Exercise for you: Find an online voltage multiplier design tool, or analog circuit simulator. Design a VM with complementary 7500 volt power sources, that delivers 30 kV across a 1.5 megohm load with one end grounded. How big, physically, are the capacitors? What's the input current?

I bet someone skilled in the art could demonstrate fusion with a multi-NST-based power supply. Do you want to learn that skill?

[Connor Givans]

Since a neon sign transformer is a center-tapped system, you could build a full-wave cockroft walton multiplier instead of the more common half-wave units. This could allow you to increase the input voltage by a factor of 3 instead of 2 on the first stage, et cetera.