Locke porcelain insulators

[Trade Journal]

Publication: American Electrician

New York, NY, United States
vol. 9, no. 2, p. 71, col. 1-3







The accompanying engravings illustrate some of the latest types of Locke high-potential insulators, which have been designed to meet the requirements incident to the development of high-voltage transmission of power. The several forms shown have withstood tests when set in steel pins, of 70,000 volts for four hours without heating, breaking down or arcing.


High Potential Insulators.


One special type of insulator, shown on the left, is composite in structure, consisting of an inner member of glass and an outer cap of porcelain; still another type is made with both portions of porcelain. By constructing these insulators with the inner member of glass, it is claimed that it is almost impossible to puncture or break down the insulation, glass offering the highest resistance against puncture, while porcelain has extremely high surface resistance. It is also claimed that by making insulators of two porcelain parts, each part may be made thinner and more easily, thus allowing for better vitrification throughout. The two parts are screwed or fused together and are very strong mechanically, as well as electrically.

The insulator on the left is designed to carry currents of from 20,000 to 40,000 volts, and those on the right for currents up to 25,000 volts. The former is used on the Niagara Falls and Buffalo transmission lines, and the latter on a number of circuits throughout the country of from 10,000 to 15,000 volts, on all of which the insulators are said to be giving perfect satisfaction. All of the above insulators are mounted on Locke steel pins with locust tips boiled in paraffine.

The insulators described are made by Fred M. Locke, Victor, N. Y.


Keywords:Fred Locke : U-937 : U-925 : U-940 : M-2121
Researcher notes:The combination insulator in the first photo is M-2121. In the second photo the insulators are U-937, U-925, and U-940; all made by Imperial Porcelain Works.
Supplemental information: 
Researcher:Elton Gish
Date completed:October 7, 2007 by: Elton Gish;