Re: Using SF6 for cap..

Tesla List wrote:
> >From kukkonen-at-cc.hut.fiFri Jul  5 11:15:59 1996
> Date: Fri, 5 Jul 1996 09:01:30 +0300 (EET DST)
> From: Kristian Ukkonen <kukkonen-at-cc.hut.fi>
> To: Tesla List <tesla-at-poodle.pupman-dot-com>
> Cc: Tesla mailing list <usa-tesla-at-usa-dot-net>
> Subject: Using SF6 for cap..
> I posted an idea about using SF6 for insulating a "standard" rolled
> LDPE&Al capasitor instead of the oil but got no replies - perhaps because
> it was at the end of a rather flaming CP comment.. The good things I have
> thought about this:
> - no danger of oil burning/exploding around
> - no air-bubbles possible, will replace air everywhere especially
>   when a vacuum is pumped first
> - SF6 can be replaced every once and a while if necessary
> - is not messy/heavy like oil, is heavier than air
> - if cap fails it's easy to fix as there's no oil to mess the setup
> etc..
> Any ideas? Comments? (I know SF6 is toxic)
> I haven't yet found data on how applicable this really is (pressure needed
> etc.) but it might be worth consideration.. I first came to this idea when
> a person working with high-power&voltage electronics (doing installations
> for power-companies) told me that oils are not used much anymore but SF6
> is - this was for xformers, switches etc..
> Just to clarify the design - SF6 is not to be used as di-electric but like
> oil to prevent corona etc..
>   Kristian Ukkonen.


Your Idea sounds nice.  I have used the stuff (SF6) a bit in the past and 
found it to be OK, but many folks aren't set up to handle and pressurize 
capacitor vessels to the required pressure- 2 ATM minimum.  A heavy 
walled PVC would be necessary. Schedule 80 or so might do OK.

Richard Hull, TCBOR