Rotating Electrical Machine Coil End Vibration Suppression

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Solution Overview

Problem

Large rotating electrical machines experience significant electromagnetic vibration at the coil end, leading to frictional wear and insulation damage due to asymmetric coil end support structures and nonuniform connection rings, which existing technologies fail to effectively suppress.

Innovation Solution

The introduction of a dummy ring with similar rigidity and mass to the connection ring, made of metal materials, is positioned in alignment with the connection ring to enhance the rigidity and uniformity of the coil end support, lowering the natural frequency and reducing vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coil end support structure is made firmer to suppress vibration, then vibration suppression improves, but structure change is limited due to physical limitations of connection rings and leads

Engineering Contradiction:
Improvevibration suppressionVSAvoidstructure change flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a dummy ring that copies the structural characteristics of the connection ring without performing electrical functions. This dummy ring is positioned at locations where connection rings are not installed, creating a symmetric structure that improves vibration suppression while maintaining the necessary electrical connectivity through the actual connection rings and leads.

Inventive Principle:
Principle #26Copying

2Stability of the object's composition

If connection rings are added to uniformize the structure in the circumferential direction, then structural uniformity improves, but device complexity increases

Engineering Contradiction:
Improvestructural uniformityVSAvoidnumber of connection rings
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The dummy ring replicates the mechanical support function of connection rings in locations where electrical connection is not required. This allows the structure to achieve circumferential uniformity and symmetry for vibration suppression without adding unnecessary electrical connection components, thus avoiding increased device complexity.

Inventive Principle:
Principle #26Copying

3Strength

If the number of connection rings is increased to enhance rigidity, then rigidity improves, but the natural frequency increases causing larger vibration

Engineering Contradiction:
ImproverigidityVSAvoidvibration reduction
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The dummy ring provides additional mechanical support to enhance the rigidity of the coil end support structure. By positioning the dummy ring symmetrically with respect to the connection ring, the overall structural rigidity is improved without creating the natural frequency issues that would arise from adding more electrical connection rings, since the dummy ring does not participate in electrical conduction.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent intentionally creates a symmetric structural arrangement by adding dummy rings to balance the asymmetry caused by the non-uniform distribution of connection rings and leads. This symmetry in the mechanical support structure uniformizes the rigidity distribution in the circumferential direction, lowering the natural frequency and reducing vibration, while the electrical connection asymmetry is maintained where necessary for functional reasons.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3648313B1Rotating electrical machine
Publication Date: 2021.12.01 MITSUBISHI POWER LTD
  • EP3648313B1 patent drawingFigure 1
  • EP3648313B1 patent drawingFigure 2
  • EP3648313B1 patent drawingFigure 3

AI summary

A rotating electrical machine of the present invention comprises a rotor; a stator disposed facing the rotor with a predetermined gap, and including a stator core and a stator coil; a high voltage bushing that outputs electricity from the stator coil to the outside; an electric power line including at least a connection ring extending in a circumferential direction, and connecting the high voltage bushing and one side of a coil end which is an axial-direction end of the stator coil to form an electrical path; and a dummy ring including a metal as a main material, and disposed in alignment with the connection ring in the circumferential direction and in a same circumference as the connection ring.