Re: Corrected di-el strength of gas

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "john cooper" <tesla-at-tesla-coil-dot-com> 


 >Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 >What is the source of the list?

The source is the CRC Handbook of Chemistry and Physics 83rd Edition 
2002-2003, page 15-34
 >
 >I'm curious, because air has a widely accepted breakdown voltage of around
 >3kV/mm, and you give 0.97.

You're right on the 3kv/mm, but the 0.97 is the di-electric strength 
relative to nitrogen, not a strict kv/mm measurement.  According to this 
handbook, the kv/mm of air with flat electrodes is 3.00, then it goes on to 
separately list two other kv/mm numbers for air, i.e., 0.4-0.7 & 1.4 
without specifying electrode type or any other conditions.  The references 
for those last two vague km/mm measurements are Kabuki, Yoshimoto, et. al. 
IEEE Trans., DEI-4, 92, 1997 and Al-Arainy, Malik and Cureshi IEEE Trans., 
DEI-1, 305, 1994.


 >----- Original Message -----
 >From: "Tesla list" <tesla-at-pupman-dot-com>
 >To: <tesla-at-pupman-dot-com>
 >Sent: Tuesday, May 04, 2004 6:36 AM
 >Subject: Corrected di-el strength of gas
 >
 >
 > > Original poster: "john cooper" <tesla-at-tesla-coil-dot-com>
 > >
 > > I posted an error for the di-electric strength of air in a previous
 > > response, the 0.4-0.7 for air was kV/mm.  Here's a new partial listing for
 > > some gasses (FWIW gases and gasses are both proper)
 > >
 > > Air, 0.97
 > > Argon, 0.18
 > > Carbon Dioxide, 0.82 - 0.88
 > > Carbon Monoxide, 1.02 - 1.05
 > > Chlorine, 1.55
 > > Helium, 0.15
 > > *Hexafluoroethane, 1.82 - 2.55
 > > Hydrogen, 0.50
 > > Methane, 1.00 - 1.13
 > > Nitrogen, 1.00
 > > Neon, 0.16 - 0.25
 > > Nitrous Oxide, 1.24
 > > *Octafluoropropane, 2.19 - 2.47
 > > *Sulfur Hexafluoride, 2.50 - 2.63
 > > Tetrachloromethane, 6.21 - 6.33
 > >
 > > *used in industry and research as di-electrics
 > >
 > > The di-el strength of a gas is measured as a comparison to Nitrogen - 1.0
 > > It was surprising for me to realize that air, which doesn't provide much
 > > quenching, is rated at 0.97; while Nitrogen, which quenches quite well, is
 > > rated at 1.00  Not much of a difference in rating for a huge difference in
 > > quenching ability.
 > > Neon & Helium could be an interesting alternatives to Argon for inducing
 > > long streamer length although neon is more expensive than helium.  Someone
 > > asked about CO2, they'd be better off with compressed air.
 > >
 > >
 > >
 > >
 > >
 >
 >
 >