Spring Bar Stator Core Attachment for Generator Vibration Control

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Solution Overview

Problem

The existing methods for attaching a generator stator core to a frame often result in vibrations due to magnetic impulses and mechanical fatigue, leading to premature failure, especially in two-pole generators, and face difficulties in field installation due to tight fits between keybars and laminations.

Innovation Solution

The use of spring bars with adjustable components and structural members that provide a vibration-absorbing connection between the generator frame and stator core, allowing for easier insertion and adjustment of donut core sections or individual laminations, and reducing torque amplification during transient events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid keybars are used to attach laminations to the frame, then structural rigidity is improved, but vibrations and mechanical fatigue increase leading to premature failure

Engineering Contradiction:
Improvestructural rigidityVSAvoidgenerator lifespan
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the mechanical parameter of the attachment system from rigid to flexible by introducing spring bars with elastic properties. The spring bars can deflect and absorb vibrations while maintaining structural support, thus reducing mechanical fatigue on the laminations and extending generator lifespan while preserving necessary structural rigidity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring bars are designed to beforehand cushion the mechanical impulses and vibrations that occur during generator operation. By incorporating elastic elements that can deflect under load, the system预先 absorbs shock loads and prevents them from transmitting directly to the laminations, reducing fatigue and preventing premature failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If tight fit between keybars and lamination grooves is used, then vibration absorption is improved, but field installation becomes difficult or impossible

Engineering Contradiction:
Improvevibration reductionVSAvoidfield installation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the dimensional parameter of the keybar-cross section to provide clearance relative to the lamination grooves. This clearance allows the laminations to be easily inserted during field installation while the spring bar's elastic properties ensure that sufficient contact pressure is maintained for effective vibration absorption and secure attachment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The attachment system transitions from a static tight fit to a dynamic flexible connection. The spring bars can deflect and adapt to installation variations, allowing easy field installation while maintaining vibration absorption capabilities through continuous elastic contact between the keybars and lamination grooves.

Inventive Principle:
Principle #15Dynamics

3Force

If rigid attachment is used, then torque transmission is improved, but torque amplification during transient events increases

Engineering Contradiction:
Improvetorque transmissionVSAvoidtorque stress
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The spring bars are designed to beforehand cushion transient torque shocks and magnetic impulses. During transient events, the elastic spring bars can deflect and absorb shock loads, preventing torque amplification and reducing peak stresses on the attachment system and laminations, while still maintaining adequate torque transmission during normal operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the mechanical impedance parameter of the attachment system by introducing elastic compliance. This allows the system to transmit steady-state torque effectively while filtering out transient torque spikes and mechanical impulses, reducing torque amplification and protecting the laminations from excessive stress.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively reduces stator vibrations, minimizes torque buildup during transient incidents, and allows for practical assembly in various generator frames, extending the lifespan of the generator by reducing mechanical stress and facilitating easier installation.

Implementation Method 1

spring bars with adjustable components and structural members that provide a vibration-absorbing connection between the generator frame and stator core

Methodology Applied
Scientific EffectVibration absorption: Damping

Implementation Method 2

spring bars with adjustable components and structural members that provide a vibration-absorbing connection

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2606553B1Arrangement and method for attaching a stator core in a generator frame
Publication Date: 2020.06.03 SIEMENS ENERGY INC
  • EP2606553B1 patent drawingFigure 1~2
  • EP2606553B1 patent drawingFigure 3
  • EP2606553B1 patent drawingFigure 4

AI summary

A generator including a generator frame (2, FIG. 1), frame rings (4) extending from an inside surface of the frame (2), stacked laminations forming a stator core (88) disposed within the generator frame (2), a spring bar (40, FIG. 2) spanning a distance between at least two frame rings (4), a first spring bar end attached to a first frame ring (4) and a second opposing spring bar end attached to a second frame ring (4), at least one bracket (80) attached to the spring bar (40); and a first and a second keybar (84) attached to the bracket (80), each keybar (84) for engaging a corresponding groove within the stator core (88).