Slip Ring Cooling via Axial Channels

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Solution Overview

Problem

Double-fed wind turbines face operational reliability issues due to excessive temperatures at the slip ring transmission area, which are exacerbated by increased performance demands, leading to higher production costs and inefficiencies in cooling methods.

Innovation Solution

An electrical contact device with a recess for coolant flow between the shaft and slip ring, featuring radial cooling channels in the carrier element and axial cooling channels, along with an air guiding element to direct coolant effectively, allowing for enhanced cooling of the slip ring and brush devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the surface area of the transmission system is increased to accommodate higher transmission currents, then the cooling capability is improved, but the manufacturing costs increase

Engineering Contradiction:
Improvecooling capabilityVSAvoidmanufacturing costs
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention introduces axial cooling channels that extend through the slip ring assembly in the axial direction, adding a new dimension to the cooling approach. This allows coolant to flow through the interior of the slip rings along the axis, providing effective cooling without increasing the radial surface area, thus avoiding higher manufacturing costs while improving cooling capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cooling system is segmented into multiple axial cooling channels distributed throughout the slip ring assembly. Each channel independently guides coolant through specific regions, allowing efficient heat removal from high-current transmission areas without requiring a uniformly large surface area, thereby reducing manufacturing costs while maintaining effective cooling.

Inventive Principle:
Principle #1Segmentation

2Temperature

If radial fans are used to draw in cooling air, then the cooling effect is improved, but the device complexity increases

Engineering Contradiction:
Improvecooling effectVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The invention uses axial cooling channels that guide coolant (air or liquid) through the slip ring assembly using fluid dynamics principles. The coolant flows axially through the channels, creating efficient heat removal through forced convection without requiring complex radial fan mechanisms, thus reducing device complexity while maintaining effective cooling.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Power

If larger slip ring assemblies are used to accommodate increasing transmission currents, then the current capacity is improved, but the manufacturing costs increase

Engineering Contradiction:
Improvetransmission current capacityVSAvoidmanufacturing costs
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The axial cooling channels are integrated directly into the slip ring assembly structure, allowing the assembly to cool itself during operation. The coolant flows through the existing structural elements of the slip rings, providing self-cooling capability that enables higher current transmission without requiring externally added cooling components, thus avoiding increased manufacturing costs while improving power capacity.

Inventive Principle:
Principle #25Self-service

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 operating temperatures, enables smaller slip ring designs, and supports higher performance levels by efficiently cooling the slip ring and brush devices, thereby improving operational reliability and reducing costs.

Implementation Method 1

a recess between the shaft (24) and the slip ring assembly (18) for guiding a coolant flow

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The first cooling channels (38) may be designed as corresponding grooves that are formed in the shaft (24) and/or the slip ring assembly (18). Coolant or cooling air can be conveyed through these first cooling channels

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 3

The support element has a plurality of secondary cooling channels for guiding the coolant, which extend substantially in the radial direction of the shaft

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2887509B1Electrical contacting device for an electric machine
Publication Date: 2021.01.27 FLENDER GMBH
  • EP2887509B1 patent drawingFigure 1
  • EP2887509B1 patent drawingFigure 2~3
  • EP2887509B1 patent drawingFigure 4~5

AI summary

The invention relates to an electrical contact device (10) for an electric machine with a brush assembly (12) comprising a brush (16), a shaft (24) rotatably mounted to the brush assembly (12), and a slip ring assembly (18) fixedly mounted on the shaft (24), wherein the slip ring assembly (18) has a slip ring (22) which is in electrical contact with the brush (16) of the brush assembly (12), and wherein the electrical contact device (10) has a recess (32) between the shaft (24) and the slip ring assembly (18) for guiding a coolant.