Slip Ring Cooling via Suction and Guiding Means

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Solution Overview

Problem

Existing slip ring assemblies in wind turbines suffer from inefficient cooling of brushes, leading to increased wear and unpredictable service life, with prior solutions either dispersing dust or providing inadequate cooling, which can harm generator components.

Innovation Solution

A slip ring assembly design where gas is sucked through guiding means positioned close to the slip ring surface, directing it to cool the surface efficiently and preventing dust from spreading, with filters to manage particles, and a configuration that maximizes gas velocity and contact duration with the slip ring to enhance cooling and reduce wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If air is blown into the housing to cool the brushes, then cooling effect is provided, but dust is spread to the generator causing harmful effects

Engineering Contradiction:
Improvebrush surface temperatureVSAvoiddust spreading
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

Instead of blowing air into the housing (which spreads dust), the invention inverts the approach by sucking air out through a suction means positioned outside the housing. This reverse airflow direction achieves cooling while preventing dust from being dispersed into the generator, directly resolving the contradiction between cooling effectiveness and dust control.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-generated harmful factors

If air is sucked out of the housing to prevent dust spreading, then dust control is improved, but cooling efficiency is insufficient

Engineering Contradiction:
Improvedust containmentVSAvoidbrush cooling efficiency
Core Design Contradiction:
Object-generated harmful factorsVSTemperature

Solution Approach 1:

The invention introduces a guiding means as an intermediary component that directs the suction airflow to follow the slip ring surface closely. This guiding means ensures the air stream maintains optimal velocity and contact duration with the brush surface, maximizing cooling efficiency while the suction means outside the housing continues to contain dust effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If gas velocity is increased to improve cooling, then cooling efficiency improves, but dust may be dispersed more widely

Engineering Contradiction:
Improvecooling efficiencyVSAvoiddust dispersion
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The invention replaces the mechanical blowing system with a suction system that operates outside the housing. The suction means creates a controlled airflow that follows the slip ring surface, maintaining high velocity for effective cooling while the external positioning prevents dust from being mechanically dispersed into the generator interior.

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

4Duration of action of moving object

If cooling duration is extended to improve cooling effect, then brush wear is reduced, but system complexity increases

Engineering Contradiction:
Improvecooling durationVSAvoidsystem complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The suction means is designed to operate continuously throughout the rotation of the slip ring, ensuring the cooling action is maintained throughout the entire operational cycle. This continuous cooling duration maximizes brush life extension without requiring complex intermittent control systems or additional components.

Inventive Principle:
Principle #20Continuity of useful action

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

Substantially reduces brush wear and maintains efficient cooling, preventing dust from harming other components while increasing the service life of brushes and improving overall system reliability.

Implementation Method 1

Gas is sucked into the housing through the inlet via the guiding means and out through the outlet by means of a suction means. The guiding means is positioned at a predetermined distance from the surface of the slip ring for guiding the gas along at least a part of the surface of the slip ring.

Methodology Applied
Scientific EffectConvection cooling: Convection

Implementation Method 2

When the brushes brush against the rings, heat is generated due to the friction.

Methodology Applied
Scientific EffectFriction heating: Friction

Data Source

PatentEP2361455B1Slip ring assembly with cooling
Publication Date: 2013.03.27 VESTAS WIND SYSTEMS AS
  • EP2361455B1 patent drawingFigure 1
  • EP2361455B1 patent drawingFigure 2
  • EP2361455B1 patent drawingFigure 3

AI summary

The present invention relates to a slip ring assembly for providing electricity to or from a rotor rotating in relation to a stator in a generator or an electrical motor. The slip ring unit rotates around a centre axis and has at least one first slip ring with an outer surface, a diameter, and a width. Also, the assembly comprises at least one conductive means, such as a brush, having conductive contact with the surface of the slip ring, and a housing in which the slip ring unit and the conductive means are situated. Furthermore, the assembly has a suction means in connection with the housing for suction of gas from within the housing out through a suction outlet in the housing. In addition, the housing has a suction inlet which is connected with a guiding means. The guiding means has an aperture facing the slip ring surface, and the aperture is positioned at a predetermined distance from the surface of the slip ring so that the gas is able to cool the surface of the slip ring. Also, the invention relates to a generator and a wind turbine having such a slip ring assembly.