On-load tap changer compression spring energy storage

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Solution Overview

Problem

The limited mechanical fatigue strength of tension springs in existing on-load tap changers becomes a disadvantage due to increased maintenance intervals caused by the high reliability of vacuum switching cells, leading to the need for springs to be replaced periodically.

Innovation Solution

An on-load tap changer with an energy accumulator featuring compression springs with adjustable force through a threaded pull rod, providing almost unlimited mechanical strength and allowing for continuous adjustment to match varying load switch requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tension springs are used in the energy accumulator, then the on-load tap changer can operate reliably, but the springs have limited mechanical fatigue strength and must be replaced periodically

Engineering Contradiction:
Improveoperational reliabilityVSAvoidservice life of springs
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the type of spring from tension spring to compression spring, fundamentally altering the mechanical stress characteristics. Compression springs have superior fatigue resistance and can endure significantly more loading cycles without failure, directly addressing the limited service life issue while maintaining operational reliability

Inventive Principle:
Principle #35Parameter changes

2Productivity

If maintenance intervals are increased to take advantage of vacuum switching reliability, then operational efficiency improves, but the tension springs become a limiting factor due to their finite fatigue strength

Engineering Contradiction:
Improvemaintenance intervalVSAvoidspring durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By transitioning from tension to compression springs, the patent enables extended maintenance intervals because compression springs can withstand significantly higher cycle counts. This parameter change in spring type directly supports longer operational periods between maintenances without compromising spring reliability

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the energy accumulator is designed for specific load switch types, then performance is optimized, but adaptability to different switch types is reduced

Engineering Contradiction:
Improveswitching performanceVSAvoidcompatibility with different switches
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent designs the energy accumulator with compression springs and an adjustable threaded rod mechanism that can be configured for different switching applications. This universal design allows the same basic structure to serve multiple load switch types and vacuum interrupter configurations, enhancing adaptability while maintaining optimized performance through adjustable spring preloads and geometries

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

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 solution enables extended maintenance intervals and adaptability to different load switch types, ensuring reliable operation with both mechanical and vacuum switching systems by using compression springs that are highly durable and resistant to breakage.

Implementation Method 1

an energy accumulator (150) in the form of a compression spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP1991998B1On-load tap changer with an energy storage mechanism
Publication Date: 2013.01.16 MASCHFAB REINHAUSEN GMBH
  • EP1991998B1 patent drawingFigure 1
  • EP1991998B1 patent drawingFigure 2

AI summary

The invention relates to an on-load tap changer having an energy storage mechanism for changing over, without any interruptions, between different winding taps of a tap-changing transformer on load. According to the invention, the energy storage mechanism has one or more compression springs, which are tensioned at the beginning of a changeover operation. In comparison with the tensile springs used to date with such energy storage mechanisms, the compression springs have markedly greater long-term strength.