High Power water capacitors
High Power water capacitors
(OP)
Distilled water has a great breakdown voltage, a great Er=80 and is cheap, but has great power losses due electrolitic current. It is possible to avoid it by placing a thin polietilene layer on plates surfaces or icing it?





RE: High Power water capacitors
RE: High Power water capacitors
Thank you for your question.
Without knowing the specifics of your application, is deionized water a possibility?
Deionized water, as the name suggests, is water with ions stripped out of it by a continual filtration process such as a bed of resin beads. A company like Culligan might still be in the business of providing these tanks of resin beads for deionization of water.
Here is a Wikipedia link about deionized water:
http://en.wikipedia.org/wiki/Deionized_water
Bob Stowe
President,
Foundation R&D, Inc.
www.frd-inc.com
RE: High Power water capacitors
was Al2O3
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: High Power water capacitors
My idea is to build a powerful and little capacitor for pulse application. The problem is that electrolisys of a big capacitor make impossible to manage great capacity because great currents and dangenous hydrogen appears.
I would need a 1 kjoule cap and 1 megavolt would be 2.8m3 but losses would be 100 megawatts
If made with transformer oil it would be 100m3 and losses would be about 16kW
Water data:
Er=80
Breakdown voltage: 1e8 V*m
Resistivity: 182 ohm*m (A friend measured 6000)
Transformer Oil data:
Er=2.2
Breakdown voltage: 4e7 V*m
Resistivity: 1E13 ohm*m
RE: High Power water capacitors
2nF 1 MV will be )*^&$&%#$# BIG !!!!
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: High Power water capacitors
This sounds like an explosion which has found a place to happen.
respectfully
RE: High Power water capacitors
1kjoule is serious. Now I am building a very little 50 joule capacitor bank (with 4 electrolitic 470uF 311V only. They are rated for 22A, 100Hz, I am not sure they support short cut discharge. It begins to be serious.
I am now looking for lowest priced and volume to stored energy for next capacitor bank for pulse testing. There are some possibilities: a compulsator and oil capacitors (it seems water ones does not work)
I think that water has a very big energy store capability due charge is transferred with ions instead of electrons
Note, I had a typing error, theorical water resistivity is 182kohm, nor 182 ohm.
RE: High Power water capacitors
RE: High Power water capacitors
The secret to using water capacitors was to charge the capacitors up fast and immediately discharge them.
If the capacitors were charged too long an explosion would result as mentioned by waross.
RE: High Power water capacitors
RE: High Power water capacitors
Even deionized water resistivity is poor compared to the resistivity of capacitor oil. So, for any high voltage application except for short uS pulses with very low duty, the resulting power dissipation would quickly boil the water resulting in gas expansion.
However, in non-capacitor applications involving high voltage,
deionized water can be effectively used for cooling of high voltage equipment since the surfaces at high and low potential are not close together.
Bob Stowe
President,
Foundation R&D, Inc.
www.frd-inc.com
RE: High Power water capacitors