Conductive Fluid Switch Idea.

[William]

The switch problem is interesting. I’m wondering if a conductive fluid switch could be constructed. I’m picturing fluid flowing through multiple ducts to simultaneously fill a large gap area. The fluid could be controlled with a high-pressure differential of helium gas on either side, which could be oscillated for continuous cyclic operation. The fluid could be tangentially circulated for cooling. I know developing such a switch is out of the question short term, but is perhaps a good long term solution. Maybe not possible to get such a switch to operate at 200 hz though. The scale would have to be such that the interface between the gas and fluid would remain intact – that is no bubbles in the fluid and no droplets in the gas. The dynamics are outside my current knowledge. Can anybody either shoot this down or prop it up? Thanks.

[KeithPickering]

The switch has to go from fully-off to fully-on in something like 20 nanoseconds. This pretty much rules out all normal physical processes, and fluid flow is most especially ruled out.

[Aeronaut]

Are there any realistic options such as perhaps diamond switches that could handle the load in a single unit or at most 4 switching units per capacitor? Also, what are the odds of the present switching technology becoming reliable right out of the box? I can’t help but believe that the switching and capacitor industries are way overdue for a Six Sigma grade rude awakening.

[Breakable]

LPP ruled out diamond switches (if I remember correctly) because none had experience making powerful enough.
William is talking about something similar to
http://en.wikipedia.org/wiki/Ignitron
which for some reason are not used (response time?)

[jamesr]

Can somebody tell me why there needs to be more than one switch?

They are all wired to the anode on the other side of the switches. One big switch has to handle the whole current load, but it completely eliminates synchronization issues.

[Aeronaut]

jamesr wrote: Can somebody tell me why there needs to be more than one switch?

They are all wired to the anode on the other side of the switches. One big switch has to handle the whole current load, but it completely eliminates synchronization issues.

I often wonder the same thing, James. On a similar note is how few caps I can get reliable ignition from. As far as I know, 2MA is too much current for today’s manufacturing technology. General Atomics sells 4 caps in 1 case that begs for a single switch and a torpedo-shaped core which contains all the wear and inspection parts for a quick and reliable service interval.

[KeithPickering]

jamesr wrote: Can somebody tell me why there needs to be more than one switch?

They are all wired to the anode on the other side of the switches. One big switch has to handle the whole current load, but it completely eliminates synchronization issues.

There are no commercially available plasma switches that can handle the current requirements. Hence the need for multiple switches that must fire simultaneously.

[jamesr]

KeithPickering wrote:
There are no commercially available plasma switches that can handle the current requirements. Hence the need for multiple switches that must fire simultaneously.

I guess that then begs the question – What would it take to design a switch that can handle the load?

[Aeronaut]

jamesr wrote:

There are no commercially available plasma switches that can handle the current requirements. Hence the need for multiple switches that must fire simultaneously.

I guess that then begs the question – What would it take to design a switch that can handle the load?

And the associated question- How difficult would it be to scale our existing switching technology to the 2-3MA range? Do we really need to start from scratch?

[AaronB]

Right now, there are 12 capacitors, each with its own switch, used for powering each pulse. The diamond switch will be used in Phase 2 to collect energy from the ion beam after a pulse. The diamond switch will have to allow current to flow into capacitors as the ions are approaching the coil and slowing down, and then quickly turn off so the coil and capacitors don’t expend the collected energy to re-accelerate the ions. Perhaps as time goes by and further development happens, we can use a single capacitor bank with two diamond switches, one for initiating the pulse and the other on the capture side. Maybe on FF-2.

[Brian H]

AaronB wrote: Right now, there are 12 capacitors, each with its own switch, used for powering each pulse. The diamond switch will be used in Phase 2 to collect energy from the ion beam after a pulse. The diamond switch will have to allow current to flow into capacitors as the ions are approaching the coil and slowing down, and then quickly turn off so the coil and capacitors don’t expend the collected energy to re-accelerate the ions. Perhaps as time goes by and further development happens, we can use a single capacitor bank with two diamond switches, one for initiating the pulse and the other on the capture side. Maybe on FF-2.

It’s just “rock” science! 😉 :cheese:

[Author]

Posts