Special Transmission Line Towers

Special Transmission Line Towers.

Energy for operating the Syracuse, Lake Shore & Northern Railway, which extends from Syracuse to Fulton, N. Y., is obtained from the generating station of the Ontario Power Company at Niagara Falls. The energy is transmitted over 60,000-volt circuits to a transformer substation in Syracuse where the e.m.f. is changed to 33,000 volts for further transmission to railway substations along the route of the above-mentioned railway. The 33,000-volt, three-phase transmission line crosses the Seneca River at Baldwinsville and the Oswego River at Phoenix. At each of these places it has been necessary to erect special transmission towers for carrying the line across the river. The span at the former place is 900 ft. in length, while that at the latter is 700 ft. A view of one of the spans is shown in Fig. 1, a side view of one of the supporting poles being given in Fig. 2. The tower measures 55 ft. in height to the lowest insulator, the other insulators being placed vertically 5 ft. apart and separated by 9 ft. horizontally. Each of the six cables was erected with a stress of 3000 lb., but the towers have been designed for an estimated maximum strain of 8000 lb. for the highest wind velocity when the cables are covered with sleet. The cable is attached by means of clamps to a saddle which rests on and is supported by six porcelain insulators mounted on wrought-iron pins. For transferring the strain of the cables to the insulators use is made of a 1-in. steel pin so placed on the saddle that there is no twisting moment on the insulators. In case repairs become necessary any one insulator may be removed without disturbing the other five, which continue to support and insulate the cable from the tower.

Fig. 1. — Towers for Span Across the Oswego River. Fig. 2. — Side View of Towers Showing Arrangement of Insulators.

Each tower is built in two parts resembling ladders. These parts are erected separately and bolted together in their final resting-places. These towers were designed and built by the Archbold-Brady Company, Syracuse, N. Y.