Rotor Spring Migration Prevention via Nested Locking

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Solution Overview

Problem

In turbine generators, the misalignment of components due to spring migration caused by heating and cooling cycles leads to blocked cooling passageways, reducing operating efficiency and causing vibration and downtime.

Innovation Solution

An assembly comprising copper windings with aligned apertures, creepage members, slot springs, amortisseurs, hollow locking members, and wedges is used to secure components within the rotor slot, ensuring continuous cooling gas flow and reducing spring migration through aligned apertures and additional securing mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional spring attachment systems are used in rotor slots, then the structure is simple and easy to manufacture, but the springs migrate outwardly over time due to heating and cooling cycles, causing misalignment of cooling passageways

Engineering Contradiction:

Improvealignment stabilityVSAvoidattachment system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements nesting by placing hollow locking members inside the apertures of槽 springs, and further nesting field retaining rings around the slot springs and locking members. This nested structure prevents spring migration while maintaining compact space utilization within the rotor slot.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The attachment system is segmented into multiple functional components: slot springs for radial pressing force, hollow locking members for positional stabilization, and field retaining rings for axial retention. Each segment performs a specific function, collectively preventing migration while allowing manufacturing of individual simple parts.

Inventive Principle:

Principle #1Segmentation

2Reliability

If components are secured tightly within rotor slots, then spring migration is prevented, but the complexity of the attachment system increases with multiple components

Engineering Contradiction:

Improvecomponent positioningVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The hollow locking members serve multiple functions: they prevent outward migration of slot springs, maintain alignment of cooling passageways, and provide structural support within the rotor slot. This multi-functionality reduces the need for separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The nested arrangement of locking members within spring apertures and retaining rings around springs allows compact integration of multiple functions into a space-efficient structure that is relatively simple to assemble.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Productivity

If slot springs are allowed to migrate outwardly, then the attachment system remains simple, but the cooling passageways become misaligned and blocked

Engineering Contradiction:

Improvecooling efficiencyVSAvoidspring retention mechanism

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The hollow locking members are pre-installed in the rotor slot and the field retaining ring is positioned before final assembly. This preliminary action ensures that when slot springs are installed, they are immediately constrained to maintain proper alignment of cooling passageways, preventing migration before it can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The nested structure of locking members within springs and retaining rings around springs creates a compact retention mechanism that prevents spring migration while minimizing interference with cooling gas flow through the aligned passageways.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Stability of the object's composition

If multiple retention components are added to prevent spring migration, then alignment stability is improved, but the device complexity and assembly difficulty increase

Engineering Contradiction:

Improvealignment stabilityVSAvoidcomponent replacement difficulty

Core Design Contradiction:

Stability of the object's compositionVSEase of repair

Solution Approach 1:

The retention system is segmented into replaceable components: hollow locking members that fit into spring apertures and field retaining rings that can be independently removed and reinstalled. This segmentation allows repair of individual components without replacing the entire attachment system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The hollow locking members and field retaining rings serve multiple functions including mechanical retention and alignment maintenance, reducing the need for additional specialized components that would further complicate repair procedures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10069367B2Modified attachment system for springs in a generator rotor

Publication Date: 2018.09.04 MECHANICAL DYNAMICS & ANALYSIS LLC

AI summary

An assembly for use in a rotor of a turbine generator is provided that includes at least one creepage disposed on an upper load surface of copper windings. At least one slot spring is disposed on the creepage, and at least one amortisseur is disposed on the slot spring. A plurality of hollow locking members are disposed within apertures of the creepage, the slot spring, and the amortisseur. At least one slot wedge is disposed on the slot spring and the plurality of hollow locking members. At least one field retaining ring is disposed against one of the end portions of the rotor body and against the slot wedge.