Informational Brochure

Switch Rotor Bearing Design Characteristics A key to the successful operation of a switch over its life is a properly designed rotor bearing. Consideration of materials and proper utilization of those materials is paramount in assuring corrosion, contamination and mechanical stress do not prevent an insulator to rotate and subsequently a switch fails to operate. The drive insulator stack of every switch rotates on a greaseless, maintenance free rotor bearing that contains two sets of stainless steel ball bearings. Weather seals prevent moisture and foreign matter from entering the rotor bearing. The two ball bearing sets are adequately spaced to handle all thrust and radial loading such as conductor weight, ice, short circuit forces and seismic considerations. Design calculations are typically used to verify product designs. Mechanical testing is equally important in validating products in real life. Pascor Atlantic rotor bearing assemblies have been subjected to numerous mechanical tests of 1000 operations or more. Short circuit current tests have been performed up to 142 kA momentary. Seismic tests have been performed to High Level (0.5g) of IEEE 693‐2005. Field history can also tell you a how well a product performs during its lifetime. Current bearing designs have been in place for over 50 years without a single complaint indicating a rotor bearing has failed to operate as intended. Pascor Atlantic’s family of rotor bearings exceeds all criteria that should be considered for a switch application. Materials are adequate to assure long term corrosion resistance. Loading of individual bearings is well below industry standards. Extensive testing over the years has validated the design and a 50 year history without a reported failure goes to further substantiate a true maintenance free bearing for the life of the switch. Galvanized steel shaft

O-ring seals top and bottom

356‐T6 aluminum housing

Double row stainless steel bearing races

Pascor Atlantic Corporation State route 42 • 254 Industry Drive • Bland, VA 24315 Tel: 276-688-3328 • Fax: 276-688-2228 www.pascoratlantic.com