MOD2 Spacer Damper

Galloping Protection for Bundled Conductors
Horizontal and Vertical Transmission Lines


Tested to 625kV phase-to-phase, the MOD2 Spacer Damper
controls galloping and rolling of the bundled conductor.
Installed at specified distances, the MOD2 Spacer Damper
system provides proper separation of the bundle, increased
torsional stiffness, effective vibration damping, and galloping
control on twin bundled lines. Galloping control is achieved
by allowing the conductors to twist independently as each
starts to gallop up and down. Twisting is the primary
method for galloping control in all
AR Products.

Expert engineering customizes the product application and
installation to features of the bundled line. This galloping
control system is specified for voltage and line by optimizing
the diameter of the hoop, the size of the clamps that attach
to the conductor, the number of clamps, the spacing of the
spacer dampers, and occasionally the composition of the

Available in models with ring diameters and clamp sizes to fit
a wide range of twin bundles, the MOD2 Spacer Damper
installs over line guards or Armor Rods.

How it works?

Articulating Clamp Feature. Articulated clamps swivel
about the spacer damper ring, allowing the unit to rotate
and twist the conductors while maintaining separation of the
bundles. The design provides stress relief in three degrees

of freedom in high-frequency Aeolian vibration and low-
frequency galloping. When installed on the bundle, this
feature allows clamp articulation at +/-90° from initial

Increased Torsional Stiffness of the Line. Alternating how
Alternating how
the spacer dampers are attached along the line (inside the
bundle|outside the bundle) creates increased stiffness of
the bundle for control of both galloping and rolling.

Strength. A steel spring ring increases the compressive
strength of the unit. By test, it was found that
compressive strength exceeds 1,800 lbs.

Galloping Control.The twisting feature of AR Product line
controls the gallop to safe limits. More than merely
reducing or synchronizing the motion, the MOD2 Spacer
Damper acts to arrest galloping as it is induced. The large
rotation angles effectively change the wind angle of attack
during galloping, a proven technology and method.

Performance Tested

MOD2 Spacer Dampers have been in service for more than
15 years, with no reported failures. The product has been
tested at NEETRAC for strength, corona, RIV and vibration

AR Clamps have been strength tested at Helical Line
Products. Slipping tests found clamp strength to exceed
4000 lbs.


  • Steel Spring Ring | 12” 18” 24” Models
  • Articulating Clamps | Six (6) sizes scaled for conductor sizes with O.D. ranging from <1.0 to 1.80
    Ring assembly may hold 2 clamps to handle a wide range of bundle designs
  • Steel Spring Ring
  • Articulating Clamps

  • 12” 18” 24” and 30” Models
    Six (6) sizes scaled for conductor sizes with O.D. ranging from <1.0 to 1.80
    Ring assembly may hold 2, 3, and 4 clamps to handle a wide range of bundle designs

    Construction and Impact on the line

    MOD2 Spacer Dampers are constructed of a steel spring ring and aluminum clamps for weight and strength. There is minimal
    structural loading on the line because of its low profile, compact design and weight. Two or more clamps are positioned at
    equal intervals around the structural hoop. Distance between the clamps is maintained by the spring covered steel hoop.

    The smooth outer edges of the AR Clamps and the recessed placement of hardware guard against corona. The smooth,
    round inner edges of the clamp and flexibility in Armor Rod choices makes the MOD2 Spacer Damper suitable for a range of
    line voltages and conductor sizes. Total weight is 18 lbs.