Adjustable Mass Load Coupling for Power Train Torsional Frequency Control
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Solution Overview
Problem
Power trains experience excessive torsional vibrations when operating at or near their natural frequencies, which can lead to damage, and existing methods are difficult to implement without substantial modifications to large and heavy turbines and generators.
Innovation Solution
A load coupling device with adjustable masses positioned in an annular array around the flange of a power train's load coupling, allowing for the modification of the moment of inertia and torsional natural frequencies, enabling the power train to operate within safe frequency margins without significant changes to existing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power train operates at or near its natural frequencies, then power generation efficiency is improved, but excessive torsional vibrations occur causing damage
Solution Approach 1:
The patent changes the physical parameters of the load coupling by adding adjustable masses to modify the moment of inertia. This shifts the torsional natural frequencies of the power train, allowing operation at optimal frequencies while avoiding resonant conditions that cause excessive vibrations. The masses can be positioned to achieve desired frequency separation margins.
2Object-affected harmful factors
If the turbines and generators are modified to shift natural frequencies, then torsional vibration problems are reduced, but substantial changes to large and heavy components are required
Solution Approach 1:
The patent introduces an intermediary device - the adjustable mass system on the load coupling - that modifies the torsional characteristics of the power train without requiring changes to the turbine or generator themselves. The load coupling acts as a mediator between the turbine and generator, providing frequency adjustment capability while leaving the primary components unchanged.
Solution Approach 2:
The patent segments the mass adjustment capability into discrete, independently positionable masses on the load coupling. This allows the moment of inertia to be modified in steps by adding or removing masses at specific locations, providing flexible frequency tuning without substantial modifications to the turbine or generator components.
3Object-affected harmful factors
If the moment of inertia of the load coupling is increased by adding masses, then the torsional natural frequencies are shifted away from operational conditions, but the device complexity increases
Solution Approach 1:
The patent makes the load coupling dynamic by providing adjustable masses that can be added or removed based on operational requirements. The mass configuration can be changed to shift torsional natural frequencies to appropriate values for different operating conditions, transforming a static component into an adaptable system.
Solution Approach 2:
The patent performs preliminary frequency analysis to determine the optimal mass configuration before final installation. By calculating the required moment of inertia modification in advance, the masses can be positioned to achieve the desired frequency separation margins, avoiding the need for iterative adjustments after installation.
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
The solution effectively adjusts the torsional natural frequencies of power trains, reducing excessive vibrations and providing adequate frequency margins during operational conditions without requiring substantial modifications to turbines or generators.
Implementation Method 1
The moment of inertia may be adjusted by arranging masses positioned in an annular array around a flange of the load coupling. By removing, adding or changing the masses, the moment of inertia of the load coupling is changed. A change in the moment of inertia moves the torsional natural frequencies for the load coupling and power train.
Data Source
AI summary
A load coupling device for a power train including: a rotatable shaft; a first flange on a first end of the shaft, wherein the first flange is adapted to couple to a first rotating shaft of at a torque producing turbine or a torque driven electrical generator; a second flange on an opposite end of the shaft, wherein the shaft is adapted to couple to a second rotating shaft of the other of the turbine and the generator, and an annular ring extending radially outward from the first flange, wherein the mass of the annular ring is selected to shift a torsional natural frequency of the power train away from an operational condition of the power train. Trim masses may be added to make fine adjustments to the torsional natural frequency of the power train.