Clamp body, keeper: aluminium alloy
Damping weights: steel / hot dip galvanized
Messenger wire: steel grade III / hot dip galvanized (alt. stainless steel A2 on request)
Screw: stainless steel, grade A2-80
Washer: stainless steel, grade 200 HV
Under certain boundary conditions, the wind causes short-wave vibrations to be generated by the wind. These vibrations cause alternating bending stresses, particularly at the suspension and tension support, which are superimposed on the static tensile and bending stresses present in the conductor cable. This can cause damage to the cable in the form of individual wire breaks or even breakage of the entire cable under continuous stress.
Vibration dampers can provide effective protection against vortex-excited cable vibrations if they are correctly dimensioned and installed in the right place. RIBE vibration dampers work according to the Stockbridge damper principle. Dampers are combined friction-resonance-types, preventing dangerous stresses at conductors by consuming energy induced to conductor by wind. They consist of a damper cable with symmetrical or asymmetrical damping masses attached to the ends. A cable clamp located between the damping masses transmits the vibrations from the conductor to the damper cable. Each vibration damper is characterised by its power-frequency curve.
In practice, a broad band of conductor resonance frequencies between 5 and 100 Hz can be expected. For this reason, a vibration damper is required to be as uniformly effective as possible in this frequency band. By designing the damping masses and the length of the damper cables accordingly, 2 to 4 resonance frequencies can develop on the damper, whereby the damper performance does not drop too sharply between the resonance frequencies. RIBE vibration dampers are designed in such a way that they have almost constant damping over a wide frequency band. This generally covers the frequency range of the conductor vibrations in which the dangerous stresses occur. The properties of the vibration damper must match those of the conductor. If this is not the case, damage may occur to the conductor directly at the attachment point of the vibration damper or the vibration damper itself may be destroyed.
RIBE vibration dampers should therefore only be used if a RIBE vibration protection study (""damper study"") is available.
The exact type of vibration damper, the number of dampers per installation location and the exact installation location are determined for you.
Therefore we need following informations from you:
- Nominal voltage
- Number of systems and earth wires
- pole list with details of the spans
- conductor configuration (single cable or bundled cable),
- Area conditions (e.g. flat area, hilly area, mountains),
- conductor route (indication of the compass direction)
- Wind and ice load zones
Information on the conductor cable:
- Structure of the conductor cables (conductor cable and earth cable),
- centre tensile stress (EDS at +10 °C),
- Cable attenuation (if no values are available, we use empirical values).
Information on existing fittings
- Suspension support:
- Type of suspension clamp rod suspension clamp or trough support clamp with or without helical rod)
- helical rod data (technical details: length, wire diameter, direction of lay, etc.)
- Anchor point:
- Type of tension clamp,
- Spacer: rigid or self-damping with existing fastening type (clamp or rod fastening)
Note:
The type of damper, the damper clamp and the number of vibration dampers to be installed are determined by RIBE.
RIBE® vibration damper with the classic screw clamp:
- Perfect adaptation of the clamping channel to the conductor diameter
- Captive clamp cap
Clamp body: aluminium alloy
Damping weights: steel, forged/ hot dip galvanized
Messenger wire: steel grade III/ hot dip galvanized
Helical rods: aluminium-clad steel
Under certain boundary conditions, the wind causes short-wave vibrations to be generated by the wind. These vibrations cause alternating bending stresses, particularly at the suspension and tension support, which are superimposed on the static tensile and bending stresses present in the conductor cable. This can cause damage to the cable in the form of individual wire breaks or even breakage of the entire cable under continuous stress.
Vibration dampers can provide effective protection against vortex-excited cable vibrations if they are correctly dimensioned and installed in the right place. RIBE vibration dampers work according to the Stockbridge damper principle. Dampers are combined friction-resonance-types, preventing dangerous stresses at conductors by consuming energy induced to conductor by wind. They consist of a damper cable with symmetrical or asymmetrical damping masses attached to the ends. A cable clamp located between the damping masses transmits the vibrations from the conductor to the damper cable. Each vibration damper is characterised by its power-frequency curve.
In practice, a broad band of conductor resonance frequencies between 5 and 100 Hz can be expected. For this reason, a vibration damper is required to be as uniformly effective as possible in this frequency band. By designing the damping masses and the length of the damper cables accordingly, 2 to 4 resonance frequencies can develop on the damper, whereby the damper performance does not drop too sharply between the resonance frequencies. RIBE vibration dampers are designed in such a way that they have almost constant damping over a wide frequency band. This generally covers the frequency range of the conductor vibrations in which the dangerous stresses occur. The properties of the vibration damper must match those of the conductor. If this is not the case, damage may occur to the conductor directly at the attachment point of the vibration damper or the vibration damper itself may be destroyed.
RIBE vibration dampers should therefore only be used if a RIBE vibration protection study (""damper study"") is available.
The exact type of vibration damper, the number of dampers per installation location and the exact installation location are determined for you.
Therefore we need following informations from you:
- Nominal voltage
- Number of systems and earth wires
- pole list with details of the spans
- conductor configuration (single cable or bundled cable),
- Area conditions (e.g. flat area, hilly area, mountains),
- conductor route (indication of the compass direction)
- Wind and ice load zones
Information on the conductor cable:
- Structure of the conductor cables (conductor cable and earth cable),
- centre tensile stress (EDS at +10 °C),
- Cable attenuation (if no values are available, we use empirical values).
Information on existing fittings
- Suspension support:
- Type of suspension clamp rod suspension clamp or trough support clamp with or without helical rod)
- helical rod data (technical details: length, wire diameter, direction of lay, etc.)
- Anchor point:
- Type of tension clamp,
- Spacer: rigid or self-damping with existing fastening type (clamp or rod fastening)
Note:
The type of damper, the damper clamp and the number of vibration dampers to be installed are determined by RIBE.
RIBE® vibration damper with helical rod attachment:
- easy installation without tools
- Correct installation easy to recognise from the ground
- lateral force-free and therefore ideal for sensitive fibre optic aerial cables
- minimised bending stress
Helical rod: Weather-proof wear-resistant plastic
Additional information
Purpose of Avibra vibration dampers is to dissipate the wind power input on the ADSS cable to prevent critical conductor stresses. The Avibra vibration damper is composed of a helically formed plastic rod. About one fifth of the overall length of the helix is of smaller diameter. This section is used to attach the damper and provides a completely reliable grip on the ADSS cable so that the damper will not slip even on slopes. The remaining length of the helix has no close contact to the cable. Due to differential motions between ADSS cable and Avibra damper, the ADSS cable vibrations are eliminated.
Installation:
1 damper per 100m span length