Rotor Busbar Attachment With Retention Disc Against Centrifugal Separation

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Solution Overview

Problem

Existing electrically excited rotors face challenges in manufacturing convenience and durability due to inadequate winding-to-busbar connections that fail to withstand centrifugal forces during rotor rotation.

Innovation Solution

A method of releasably attaching a busbar to a conductor element of the rotor winding using a binding mechanism, such as encircling and folding, which eliminates the need for expensive tools and provides a secure connection, further secured by a retention disc to prevent separation under centrifugal forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional winding-to-busbar connections are used, then the rotor can be manufactured, but the connection fails to withstand centrifugal forces during rotation

Engineering Contradiction:
Improveconnection durabilityVSAvoidmanufacturing convenience
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The connection is divided into modular components: a retention disc with retention elements, a busbar with engagement features, and a conductor element. This segmentation allows each component to be optimized independently while ensuring the connection can withstand centrifugal forces through the distributed retention mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retention disc and retention elements are pre-installed on the rotor before the busbar is attached. This preliminary action ensures that the retention mechanism is already in place to secure the busbar against centrifugal forces during the attachment process and subsequent operation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If secure winding-to-busbar connections are implemented to withstand centrifugal forces, then connection durability improves, but manufacturing complexity increases

Engineering Contradiction:
Improveconnection durabilityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The retention elements are designed to automatically engage with corresponding features on the busbar through the natural centrifugal force during rotation. The centrifugal force itself becomes part of the locking mechanism, eliminating the need for additional active retention systems and reducing overall device complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The retention disc is integrated with the rotor structure, and the retention elements are combined with the busbar design. This merging of functions into existing components rather than adding separate retention systems reduces the overall device complexity while maintaining connection durability.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If conventional attachment methods are used, then manufacturing process is simple, but the connection fails under centrifugal power

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidconnection strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The retention elements utilize curved or arc-shaped geometries that conform to the rotational motion and centrifugal force distribution. This curvature allows the retention features to engage more effectively under centrifugal loading while maintaining a relatively simple manufacturing process using standard forming techniques.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The attachment mechanism utilizes changes in geometric parameters under centrifugal force - specifically, the outward radial movement and tensioning of the conductor element and busbar under centrifugal load enhances the engagement of retention features, transforming the operational conditions into a strengthening mechanism.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4489267A1A method for attaching a busbar to a rotor winding of a rotor
Publication Date: 2025.01.08 POLESTAR PERFORMANCE
  • EP4489267A1 patent drawingFigure 1
  • EP4489267A1 patent drawingFigure 2
  • EP4489267A1 patent drawingFigure 3

AI summary

The present disclosure relates to a method (100) for attaching at least a first busbar of a transmitting arrangement of an electric motor to a rotor winding of a rotor of said electric motor to enable DC power to be supplied from said transmitting arrangement to said rotor winding, the method (100) comprising the step of releasably attaching (110) a first end portion of said at least first busbar to a conductor element of said rotor winding. The disclosure further relates to a rotor (50) comprising a first busbar (30) having a first end portion (30a) releasably attached to a conductor element (21) of said rotor winding (20).