How Insulators Are Tested

[Trade Journal]

Publication: The Commoner and Glassworker

Pittsburgh, PA, United States
vol. 27, no. 43, p. 7, col. 3-4

How Insulators Are Tested

Defects in insulators may be due, not to improper constituent parts, but to annealing. They may be discovered by means of polarized light. Each insulator is mounted, for purpose of test, so that when rotated about its pin axis the same thickness of glass skirt is between the polarizer and analyzer, which has previously been arranged so as to allow no light to pass. Stressness in the insulator are shown by varying intensity to light and by color changes, being due to improper annealing. Under service conditions the insulators become heated owing to conductive leakage, and are destroyed if the annealing has not been carefully done.


Researcher notes: 
Supplemental information: 
Researcher:Bob Stahr
Date completed:February 17, 2008 by: David Wiecek;