Embedded Shaft Slipring Brush Layout for Compact Exciter Power Transfer

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Solution Overview

Problem

There is a lack of effective brush power transfer mechanisms for separately excited machines, leading to issues such as increased axial length, need for dry environments, and potential for brush wear and frictional losses.

Innovation Solution

A power transfer system for separately excited machines utilizing positive and negative sliprings, brushes, and a hollow shaft with integrated position sensors and a shaft ingress separator, which supports the wires and separates wet and dry areas, reducing the need for additional components and optimizing heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If conventional brush power transfer mechanisms are used for separately excited machines, then power transfer is achieved, but axial length increases and dry environments are required

Engineering Contradiction:

Improveaxial lengthVSAvoidoperational flexibility

Core Design Contradiction:

Length of moving objectVSProductivity

Solution Approach 1:

The patent combines the positive and negative brush assemblies into a single integrated brush carrier structure that rotates with the rotor. This merging of previously separate components reduces the overall axial length while maintaining the necessary power transfer functionality for both field windings simultaneously

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from a static brush arrangement to a rotating brush carrier that moves with the rotor. This dimensional change from stationary to rotating components allows power transfer without requiring the machine to be operated in dry environments, as the rotating carrier can incorporate sealing and lubrication mechanisms

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If conventional brush power transfer mechanisms are used, then power transfer is achieved, but brush wear and frictional losses occur

Engineering Contradiction:

Improvebrush durabilityVSAvoidfrictional losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The brush carrier is designed to rotate with the rotor and automatically position the brushes against the slip rings through centrifugal force and spring pressure. This self-positioning mechanism reduces the need for external adjustment mechanisms and minimizes frictional losses by maintaining optimal contact pressure without requiring additional energy input

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent changes the operational parameters of the brush assembly by incorporating lubrication mechanisms and adjusting contact pressure dynamically. These parameter changes reduce brush wear and frictional losses while maintaining reliable power transfer across the slip ring interface

Inventive Principle:

Principle #35Parameter changes

3Strength

If rotor laminations are pressed onto hollow shaft, then structural integrity is improved, but electromagnetic interference increases

Engineering Contradiction:

Improvestructural integrityVSAvoidelectromagnetic interference

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The hollow shaft acts as an intermediary component between the rotor laminations and the external environment. By maintaining a hollow internal passage, it provides structural integrity while allowing magnetic field lines to pass through uncontaminated, thereby reducing electromagnetic interference with surrounding components

Inventive Principle:

Principle #24Intermediary (Mediator)

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 system reduces axial length, allows higher speed operation, mitigates electromagnetic interference, and eliminates the need for dry environments, while minimizing brush wear and frictional losses.

Implementation Method 1

the rotor laminations are pressed onto the hollow shaft

Methodology Applied

Scientific EffectMechanical Pressure: Mechanical Force

Implementation Method 2

the shaft ingress separator may be included within the hollow shaft, such that the shaft ingress separator is a barrier between wet areas and dry areas

Methodology Applied

Scientific EffectPhysical Barrier: Physical Containment

Implementation Method 3

one or more positive brushes operatively in contact with the positive slipring; one or more negative brushes operatively in contact with the negative slipring

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 4

optimizing heat dissipation

Methodology Applied

Scientific EffectThermal Radiation: Thermal Radiation

Data Source

PatentUS12483100B2Shaft embedded brush power transfer for separately excited machine power

Publication Date: 2025.11.25 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A power transfer system for a separately excited machine includes a positive slipring and a negative slipring. One or more positive brushes and one or more negative brushes. A rotor winding attached to rotor laminations and a stator winding attached to stator laminations, such that the stator winding is outside of the rotor winding. The power transfer system may have a hollow shaft. The power transfer system may also have the negative brush and the negative slipring being exterior to the hollow shaft, and one or more position sensors. A shaft ingress separator may be within the hollow shaft and may act as a barrier between wet areas and dry areas. The power transfer system may also include a positive wire and a negative wire, which may be reversed.