The Italian Guido Semenza insulator

[Trade Journal]

Publication: Electrical World

New York, NY, United States
vol. 53, no. 3, p. 148-149, col. 2, 1

Umbrella-Type Insulators.

The chief point to be kept in view in designing insulators for very high voltages is to avoid superficial disruptive discharges, especially when the insulators are exposed to heavy rains. The outer petticoat, on the top of which the conductor is secured, extends outwardly to a considerable extent to protect the smaller and lower petticoats from water. When the upper petticoat has got wet, its potential is the same as that of the conductor, wherefore its upper surface is quite inefficient from the point of view of insulation. Moreover, the water drops, falling down from the upper petticoat, when succeeding each other at short intervals, offer an eas