Slip Ring Unit Pressurized Cooling for Wind Turbines

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Solution Overview

Problem

Conventional slip ring units in wind turbines face reliability and service life issues due to overheating and contamination from environmental particles, especially in arid areas with high wind speeds, which reduces their effectiveness in transmitting electrical currents.

Innovation Solution

A slip ring unit design that includes a protected sliding contact between a stator and rotor, integrated with an air conveying device and filter to create a pressurized interior environment, minimizing contamination and overheating, using a roller bearing and mechanical or electric drive for the air conveying device, and featuring seals to maintain low air flow and high internal pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the sliding contact is exposed to the environment for cooling, then heat dissipation is improved, but contamination from environmental particles increases

Engineering Contradiction:
Improveheat dissipationVSAvoidcontamination from environmental particles
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent creates a protected interior environment within the housing that is sealed from the external environment. This inert/protected atmosphere prevents environmental particles (dust, sand, etc.) from contaminating the sliding contact between slip ring brushes and slip rings, while still allowing the system to operate in harsh external conditions such as arid areas with high wind speeds.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent employs an air conveying device that introduces filtered air into the housing interior, creating a pressurized environment. This pneumatic system maintains positive pressure inside the housing, preventing unfiltered ambient air and particles from entering through seals or gaps, thus protecting the sliding contact from contamination while enabling controlled cooling.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If the sliding contact is protected from environmental influences, then reliability is improved, but heat dissipation capability deteriorates

Engineering Contradiction:
Improveservice life of slip ring unitVSAvoidheat dissipation capability
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The air conveying device introduces filtered air into the housing interior, creating a controlled pneumatic environment. This pressurized filtered air flow provides cooling to the sliding contact components while preventing unfiltered ambient particles from entering, thus simultaneously improving reliability and maintaining heat dissipation capability.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent introduces filtered air as an intermediary substance between the external environment and the sliding contact. This intermediary provides both cooling (heat dissipation) and protection (preventing contamination) functions, resolving the contradiction between reliability and heat dissipation capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If ambient air is used for cooling without filtration, then heat dissipation is improved, but contamination of the sliding contact increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcontamination of sliding contact
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a filter as an intermediary component in the air path. The filter cleans the ambient air before it enters the housing interior, removing particles and contaminants while allowing the air to continue providing cooling. This resolves the contradiction by modifying the intermediary (air) to provide both cooling and protection functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The air conveying device combined with the filter creates a pneumatic system that delivers cleaned air to the interior. This system maintains cooling efficiency by ensuring continuous air flow while eliminating contamination through filtration, thus resolving the contradiction between cooling efficiency and contamination prevention.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Object-affected harmful factors

If a pressurized interior environment is created, then contamination is prevented, but device complexity increases

Engineering Contradiction:
Improvecontamination preventionVSAvoidcomplexity of air conveying system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The air conveying device performs multiple functions simultaneously: it introduces filtered air for cooling, creates positive pressure to prevent contamination ingress, and can be integrated with the existing motor fan wheel structure. This multi-functionality reduces the need for separate systems and minimizes overall device complexity while achieving contamination prevention.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent integrates the air conveying function with the existing motor structure by utilizing the motor's fan wheel for air intake and conveying. This merging of functions reduces the number of separate components and simplifies the overall system design while still achieving the pressurized protected environment.

Inventive Principle:
Principle #5Merging (Combining)

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

The design enhances the reliability and service life of slip ring units by protecting the sliding contact from environmental influences, maintaining high internal pressure to prevent contamination, and reducing overheating, thus ensuring efficient and long-term operation in harsh conditions.

Implementation Method 1

ambient air can be conveyed through the air conveying device through the filter to separate contaminants and the filtered air can be introduced into the interior, so that a pressure can be generated in the interior of the housing that is above the pressure of the ambient air

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

ambient air can be conveyed through the air conveying device through the filter to separate contaminants

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 3

a roller bearing is arranged between the component groups that can rotate relative to one another

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 4

the one roller bearing or the plurality of roller bearings can each include a seal, so that the air that can escape through the roller bearing is minimized

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP2450571B1Slip ring unit and use of the slip ring unit in a wind power assembly
Publication Date: 2014.03.26 LTN SERVOTECHN
  • EP2450571B1 patent drawingFigure 1
  • EP2450571B1 patent drawingFigure 2

AI summary

The invention relates to a slip ring assembly with a first and a second component group (1, 2) which are rotatably arranged relative to each other about an axis (A). The first component group (1) comprises at least one slip ring brush (1.2) and the second component group (2) at least one slip ring (2.2). The slip ring brush (1.2) and the slip ring (2.2) contact each other in an interior space (1) of a housing (1.1). The slip ring assembly has an air conveying device (1.5) and a filter (1.4), wherein ambient air can be conveyed through the filter (1.4) by the air conveying device (1.5) to remove contaminants, and the filtered air can be introduced into the interior space (1), so that a pressure (pi) can be generated in the interior space (1) of the housing (1.1) which is higher than the pressure (p∞) of the ambient air.