[TowerTalk] ferrites & fires

[Chuck Counselman]

At 9:50 AM -0700 6/28/03, Jim Lux wrote:
>UF6 is hideous corrosive stuff....  You're thinking Sulfur 
>Hexafluoride (SF6), very dense (1/2 pound/cu ft!), inert, good 
>insulator for
>HV, but sadly, somewhat expensive and hard to get a hold of.  They 
>use it in Gas Insulated Switchgear (GIS) where lack of flammability 
>and packing
>density is needed (underground substations in cities, for instance).  They
>also use it in lab HV gear where close distances and HV are needed at the
>same time, and they don't want to fool with oil. I don't think it's much
>used for long distance cables, though.


You're right; I meant SF6.  A close friend, also a ham, developed 
high-voltage (about 1 MV, IIRC), DC, gas-filled, underground 
power-transmission lines -- first in the HV lab at MIT, then at two 
big industrial firms in that business.  From time to time I visited 
him in his lab.  It was great fun seeing his man-size toys.  His 
transmission lines were filled with SF6.  It never occurred to me to 
ask where he bought the stuff or what it cost.  He never made it 
sound very special, or precious.

You can get _anything_ in Cambridge, MA.  :-)

73  -Chuck, W1HIS