Electrochemistry: Liquid Power Resistor for 2000VAC

[D from BC]

This is Sandia's Z-pinch fusion machine. All the final HV stuff is in
a big swimming pool, insulated by pure water.

http://zpinch.sandia.gov/Z/Images/z.jpg

http://www.sandia.gov/media/images/jpg/Z02.jpg

"When the accelerator fires, powerful electrical pulses are delivered
by 36 transmission cables protected by insulation techniques developed
over the last 30 years. Highly synchronized laser-triggered switches
allow the stored energy to be discharged simultaneously through the 36
cables, each as big around as a horse and 30 feet long, arranged like
spokes of a wheel and insulated by water. The enormous electrical
pulse of 50 trillion watts strikes a complex target about the size of
a spool of thread."

John

Cool..
Looks like something out of a sci-fi movie..

 

[JosephKK]

iic resistivity of pure water is 18.2Mohm cm^2/cm at 25C

^^^^^^^^^^
It won't stay pure when you place the resistor pack within, let
alone when you apply voltage.

 

[JosephKK]

lol..
Too laborous but 0.25W resistors are cheap.

If I were to do that, I might just glue them all to a heat sink instead
of using a fan.

That would give you insulation breakdown problems.

 

[D from BC]

That would give you insulation breakdown problems.

True..
Two parameters in conflict, thermal coupling and electrical isolation.
I probably thought of using nonconductive thermal epoxy.

 

[pimpom]

True..
Two parameters in conflict, thermal coupling and electrical
isolation.
I probably thought of using nonconductive thermal epoxy.

Did you see my suggestion to fix the resistors with epoxy to a
plastic box and then put some water in the box?

 

[Sarason]

I'm setting up a test circuit and I need a 100k resistor that can handle
2000VAC for a few seconds.

I was going to run off to the local surplus shop but got the idea of
making a liquid resistor. Saves a trip.

I added some salt to water and got 100kohm. Copper electrodes (all I got
at the moment).

Question is... Will this stay 100kohm +/- 10kohm up to 2000VAC?
My circuit only needs to run for 5 seconds.

iows...Does salty water resistance vary with voltage?

Of course it does, look up any high school text on electro-chemistry.
Acid dissociation constant is a good phrase. Electrovalency etc.
Wikipedia has a reasonable article.