Stator Bar Connection Using Mechanical Pressing

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Solution Overview

Problem

Brazing operations for connecting stator bars and phase rings in electric machines are time-consuming, costly, and require specialized equipment, posing challenges during maintenance when high-pressure water and specific equipment are not available, and alternative screwed connections are also expensive due to material preparation and strict tolerances.

Innovation Solution

The use of connecting elements with conductive plates and tightening elements, such as bolts, that allow for secure and low-resistance electrical connections without the need for surface preparation or high-pressure application, using conductive materials like copper alloys and protective frames to ensure efficient power transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If brazing is used to connect stator bars and phase rings, then the connection is efficient and reliable, but the maintenance operation becomes time-consuming and expensive due to specialized equipment requirements

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmaintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the thermal brazing process with a mechanical pressing system. A pressing device applies controlled force through a pressing element to create reliable electrical connections between stator bars and phase rings without requiring heat, brazing equipment, or specialized materials. This mechanical substitution eliminates the need for complex brazing operations during maintenance while maintaining connection reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a pressing element as an intermediary component that facilitates the connection between stator bars and phase rings. This pressing element transfers the pressing force uniformly and creates reliable electrical contact without requiring direct brazing between the components, thereby simplifying the maintenance process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If brazing equipment is used for field maintenance, then connections can be made, but the equipment complexity and cost increase significantly

Engineering Contradiction:
Improveconnection easeVSAvoidequipment complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces complex thermal brazing equipment with a simple mechanical pressing device. The pressing device consists of basic mechanical components that can be easily transported and operated in the field, eliminating the need for sophisticated brazing equipment, power supplies, and specialized facilities.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a pressing element that can be easily replaced after use. This disposable or single-use component simplifies the overall system complexity, as the expensive pressing device needs to be used only once per connection, and the pressing element itself is inexpensive and can be discarded or replaced without affecting the main equipment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of repair

If screwed connections are used instead of brazing, then maintenance becomes easier, but the cost increases due to material preparation and strict tolerances

Engineering Contradiction:
Improvemaintenance easeVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of repairVSEase of manufacture

Solution Approach 1:

The patent replaces screwed connections with a pressing mechanism that creates reliable electrical contacts through controlled mechanical force. This eliminates the need for threaded holes, screws, and associated material preparation such as silvering, thereby reducing manufacturing costs while maintaining ease of maintenance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the connection parameter from mechanical threading (screws) to controlled pressing force. This parameter change eliminates the need for strict tolerance requirements and material preparation associated with screwed connections, while still achieving reliable electrical connections that are easy to make and maintain.

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 method reduces maintenance costs and time by providing a reliable, low-resistance electrical connection that can be performed on-site without the need for brazing equipment, ensuring efficient power transmission and reducing operational expenses compared to traditional methods.

Implementation Method 1

The use of connecting elements with conductive plates and tightening elements, such as bolts, that allow for secure and low-resistance electrical connections

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2831983B1Electric machine and assembling method
Publication Date: 2020.02.05 GENERAL ELECTRIC TECH GMBH
  • EP2831983B1 patent drawingFigure 1
  • EP2831983B1 patent drawingFigure 2~3
  • EP2831983B1 patent drawingFigure 4~7

AI summary

The electric machine (1) comprises a stator (3) including stator windings (4), the stator windings (4) comprising stator bars (5) connected each other. The electric machine (1) also includes phase rings (6) connected to the stator windings (4) and a rotor (8). The reciprocally connected parts of the stator bars (5) and/or the stator bars (5) and phase rings (6) are connected though a connecting element (12) comprising portions (17) penetrating the parts of the stator bars (5) and/or stator bars (5) and phase rings (6).