Many Motion Control devices have been tested since the first transmission lines were constructed and time has shown Stockbridge dampers are the most effective way to control aeolian vibrations. AFL currently offers two versions of Stockbridge dampers, the 1700 and 1700AA series.
The design of a Stockbridge damper is such that the weights are used to target different resonant frequencies. The weights will shake at the end of the weight at a lower frequency and then on the inside near the clamp at higher frequencies. The messenger wire will vibrate the most at these resonant frequencies and dissipate higher levels of vibrational energy through inter-strand friction/heat.
The 1700 series is AFL’s original damper designs using two of the same weights to target two vibrational frequencies. Conversely, the 1700AA is its newer style of damper that uses two different weights to target four vibrational resonances. The different styles AFL offers are shown below:
Both the 1700 and 1700AA series assemblies are interchangeable and either one can be used when in the matching conductor diameter range. For instance, any conductor that uses a 1706 damper can also use the 1706AA, and the same for the 1707AA and 1708AA. Even though the two designs are slightly different, they have very similar performances across the aeolian wind speed range (2-15mph) and are sure to offer protection from aeolian fatigue.
For more information or test documents, please refer to our Motion Control product page.