Rotational Eddy Current Damper for Low-Speed Vibration Absorption
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Solution Overview
Problem
Existing vibration dampers for tall and slim structures, such as wind turbines, face challenges in achieving adequate damping, especially at low kinetic energies and slow movements, due to insufficient eddy current field forces and high temperature dependence, which limits their effectiveness and increases costs and space requirements.
Innovation Solution
The solution involves converting linear movement of a pendulum absorber into rotational movement, utilizing an eddy current damping system with conductor and magnet elements, where the rotating conductor elements can achieve speeds 2-20 times that of fixed magnet elements, enhancing damping effect and facilitating easier heat dissipation through passive or active cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional eddy current dampers are used with linear movement, then the damping effect is insufficient at low kinetic energies and slow movements, but converting to rotational movement increases the damping effect significantly
Solution Approach 1:
The patent converts linear movement to rotational movement using a crank mechanism with a crank arm and crank axis. This curvature-based conversion allows the pendulum's linear oscillation to be transformed into rotational motion of the conductor element, enabling effective eddy current damping even at low kinetic energies where linear movement would be insufficient.
Solution Approach 2:
The patent introduces a crank arm as an intermediary component between the pendulum mass and the conductor element. This intermediary mechanism mediates the energy transfer by converting the linear displacement of the pendulum into rotational motion of the conductor, thereby enhancing the damping effect without requiring direct linear movement of the conductor through the magnetic field.
2Reliability
If the speed of conductor elements is increased to enhance damping, then heat generation increases, but rotational design facilitates easier heat dissipation
Solution Approach 1:
The rotational design of the conductor element spinning around the crank axis naturally facilitates heat dissipation through the rotational motion itself. The continuous rotation exposes different surfaces to the surrounding environment, enhancing convective heat transfer, while the centrifugal effects generated during rotation also promote heat distribution and dissipation throughout the conductor material.
3Length of stationary object
If pendulum absorbers are used in tall structures, then only small swing distances can be covered due to limited space, but this requires large absorber masses to achieve adequate damping
Solution Approach 1:
The crank mechanism converts the limited linear swing distance of the pendulum into a larger rotational path of the conductor element. By leveraging the rotational motion, the effective path length through the magnetic field is increased, allowing smaller masses to achieve the same damping effect that would require much larger masses in a purely linear configuration.
Solution Approach 2:
The patent changes the motion parameter from linear displacement to rotational velocity. The rotational speed of the conductor element can be optimized to achieve maximum eddy current damping effect, allowing the system to compensate for the limited swing distance by increasing the effective velocity parameter through the rotational conversion mechanism.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach achieves a significantly higher damping effect, up to 4-400 times that of conventional eddy current dampers, with improved temperature independence and reduced heat generation, effectively addressing the limitations of existing systems.
Implementation Method 1
If use is made of an eddy current damping system, in which conductor elements and magnet elements are moved relative to one another by rotation, it is possible to generate a high damping effect
Implementation Method 2
Eddy current dampers are functionally based on the induction of a current in an electrical conductor which is moved by a changing magnetic field. The resultant eddy currents in turn form magnetic fields, which counters the original magnetic field and brakes the movement of the conductor.
Data Source
AI summary
A novel rotation vibration damper and to vibration absorbers having the damper for wind turbines or other high and, relative to the height thereof, narrow installations or buildings. The disclosure particularly relates to vibration absorbers comprising at least one oscillating mass on a pendulum cable or pendulum rod, wherein the mass is caused to vibrate by an excitation frequency which can be damped by a rotation damper and, in particular, a rotating eddy current magnet damper which forms part of the absorber.