Ohio Brass insulator styles

High-Tension Porcelain Insulators.

In the manufacture of high-grade porcelain for insulators there are required as many as eight different kinds of clay secured from various parts of this country and Europe. One of the secrets of success in manufacturing porcelain for electrical purposes resides in the mixing of the clay; a mixture that is good for one type of insulator is not correct for another, and experience alone dictates the character of the mixture required. After the proper mixture has been obtained and worked through to the point of manufacture, then skilled labor is necessary for the purpose of making up the different types of insulators. Skilled labor is again required in the drying and glazing process and during the burning in the kilns.

Although the glazing itself does not add materially to the dielectric qualities of an insulator, yet it is important for the insulator to have a smooth surface exposed to the weather so as not to collect or hold moisture or dirt. One of the most important features in the production of high-tension insulators is the tests to which they are subjected to insure a proper factor of safety by ascertaining its ability to withstand the voltage assigned to it without breaking down or arcing over under various climatic conditions.

Fig. 1. - Insulator, 5000 Volts : Fig. 2. - Insulator, 60,000 Volts.

The accompanying illustrations show porcelain insulators constructed by the Ohio Brass Company, Mansfield, Ohio. It will be observed that while a goon-volt insulator is made in one piece, a 60,000-volt insulator is built up of four pieces. The several parts are held together by the best quality of Portland cement, which is frequently applied before the insulator is shipped from the factory.