Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Power Line Insulators



I believe the statements about path length are correct. However, I think
William Beaty was also beginning to get close to another reason for the
regularly spaced undulations. Since there is some leakage along the surface
(and hence a resistance less than infinity for the insulator), the convex
surfaces act somewhat like equipotential surfaces, and the regular spacing
helps make the potential fall in an orderly fashion from the high potential
to the ground.

The insulating towers of large van de Graaff generators or other
high-voltage generators often have properly spaced conductive rings
separated by insulators and connected by high resistances. This sets up a
well defined potential gradient rather than an uncontrolled potential
gradient. If the potential gradient from high potential to ground is well
defined and more gradual, the electric field is not as likely to exceed the
dielectric breakdown of air, and a spark cannot be created and/or cannot
easily propagate.


Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817