Bridge cables fail, thermoplastic elastomer to the rescue
Canadian Plastics
When large rubber-insulated cables for a lift bridge connecting the states of Minnesota and Wisconsin failed after less than two years in service, industrial cable manufacturer Northwire Inc. found a ...
When large rubber-insulated cables for a lift bridge connecting the states of Minnesota and Wisconsin failed after less than two years in service, industrial cable manufacturer Northwire Inc. found a ready solution in replacement cables insulated with DuPont Hytrel thermoplastic elastomer.
Hytrel provides effective electrical insulation and toughness in thin layers, according to DuPont, which allowed the replacement cables to be 40 per cent smaller in diameter than those that failed. “Smaller cable diameter means longer flex life at a given bend radius,” said Ted Beach, director of sales for Osceola, Wis.-based Northwire.
Hytrel is particularly well suited for cables that flex because its combination of high dielectric strength and toughness allows its use in thinner layers than many alternative materials, Beach added.
The old cable, which used ethylene-propylene rubber for insulation, measured 1.86 inches (47 mm) in diameter; the diameter of the replacement cable is 1.1 inches (28 mm). Its conductors are each insulated with 0.010 inches (0.25 mm) of Hytrel.
E. I. du Pont Canada Company (Mississauga, Ont.); www.plastics.dupont.com; 1-800-387-2122