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Placement of Dampers Off Armor Rods

For placements of dampers at suspension shoes with no armor rods, vibrational waves will reflect uniformly, and their wavelengths are often well defined. AFL has performed extensive testing to show that one properly placed damper can offer the proper amount of protection, in this case at the suspension. However, AFL has found that when armor rods or formed wire bushing suspension units are introduced, the vibrational wave can become variable and not be as well defined due to the effects of the rods or suspension attachment. This is likely due to the additional flexural rigidity supplied by the armor rods at the suspension.

A damper placement recommendation can be given to place a single damper over the armor rods, but AFL typically recommends placing two dampers on the bare conductor past the rods. By placing two dampers in a pair, there is better coverage over the aeolian wind range, and it is ensured that at least one damper is not located on a point of no vibrations called a node. This holds true for dead end structures as well where the insulator strings past the dead end can have a similar effect. This is why AFL will typically recommend two dampers be installed at all dead end structures.

Note: Wave forms are not to scale.