Metropolitan Electric span wire insulator

[Trade Journal]

Publication: Electrical Industries

Chicago, IL, United States
vol. 5, no. 8, p. 256-257, col. 2,1

Specialties of the Metropolitan Electric Company.

The accompanying cuts show a span wire insulator and a Lowell lag-screw wrench which are handled by the Metropolitan Electric Company, Chicago. This insulator, Fig. 1., is designed for insulating span wires on overhead construction of electrical railways. It is also well adapted for suspending arc lamps or other work where a strong durable insulator is desired. As a circuit breaker on electric lines it possesses the necessary qualities. The ball is made of tough green glass. It is three inches in diameter and has two grooves running part way around it at right angles to each other. Loops of seven-stranded steel wire, which have previously been dipped in P. & B. insulating compound, pass through these grooves. Perfect insulation is assured. A malleable iron casting is fastened to the end of each loop to which the span or other wire is attached. It is said this insulator will stand a strain of 6,000 pounds and that the most severe changes of weather do not affect its insulation. The practical use of this device has shown its utility under the varying conditions of weather and service.


Fig. 1. Specialties of the Metropolitan Electric Company.


In Fig. 2 is shown the Lowel lag screw wrench. Its usefulness, especially in line construction, is at once apparent. For telephone and telegraph work as well as for all overhead construction this is a most important tool. In fastening the cross-arm to the standing pole this wrench is a handy tool. The insecurity of the footing gives the hands and arms of the workman but partial liberty but sufficient to use this tool advantageously. Different sockets fitting screws of different sizes can be quickly inserted or removed. The wrench is strongly made and very simple. It is used extensively by fire alarm and telegraph constructors. Workmen with this wrench are more apt to turn the screw in than to drive it and better work is therefore secured.


Fig. 2. Specialties of the Metropolitan Electric Company.



Keywords:Strain Insulator : Glass
Researcher notes: 
Supplemental information: 
Researcher:Bob Stahr
Date completed:June 19, 2009 by: Bob Stahr;