Overvoltage Protection Device with Mechanical Arresting Mechanism

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Solution Overview

Problem

Existing overvoltage protection devices with mechanical disconnection devices face issues of high costs due to the need for multiple disconnecting devices and insufficient electrical separation caused by solder threads during thermal overload, as well as the constant mechanical force applied to solder connections, which limits surge current capacity and material efficiency.

Innovation Solution

The design features parallel conductor sections that attract each other under surge current, reducing the mechanical load on the solder point and allowing for a lower spring force in the disconnecting device, while using a pair of current-dividing metal brackets and a wedge-shaped slider to ensure safe, tension-free separation without solder threads, and encapsulating varistors in a housing with specific material requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solder is used to secure connection elements in the closed position, then the connection is reliable, but the solder point is constantly subjected to mechanical force-side load which limits surge current capacity

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmechanical force on solder point
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The connection elements utilize the surge current itself to generate the necessary contact pressure through electromagnetic forces, eliminating the need for constant mechanical preloading on the solder joint. The system serves itself by using the electrical current to create the mechanical pressure needed for reliable connection during surge events.

Inventive Principle:
Principle #25Self-service

2Power

If multiple disconnecting devices are used to increase surge current carrying capacity, then the surge current capacity increases, but the costs increase

Engineering Contradiction:
Improvesurge current carrying capacityVSAvoidnumber of disconnecting devices
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

Multiple connection elements are combined into a single integrated disconnecting device structure, where parallel conductor sections work together to handle high surge currents. The design merges the functions of multiple separate disconnecting devices into one unified component that achieves the same surge current capacity without requiring multiple separate units.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If solid slides are used for separation, then the separation is simple, but solder particles are entrained forming solder threads which cause insufficient electrical separation

Engineering Contradiction:
Improveseparation simplicityVSAvoidelectrical separation quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention uses a thin, flexible separating element that can cleanly part the connection elements without disturbing the solder joint. This thin film-like separator moves through the connection elements during separation, preventing solder particles from being entrained and forming threads, thereby achieving clean electrical separation.

Inventive Principle:
Principle #30Flexible shells and thin films

4Power

If conductor sections are dimensioned for high surge current capacity, then the surge current capacity increases, but the material costs increase

Engineering Contradiction:
Improvesurge current capacityVSAvoidconductor material quantity
Core Design Contradiction:
PowerVSQuantity of substance

Solution Approach 1:

The conductor path is segmented into multiple parallel sections that share the surge current load. By dividing the current path into parallel branches, each conductor section can be dimensioned more economically while the combined parallel structure achieves the required total surge current capacity, reducing the total quantity of conductor material needed.

Inventive Principle:
Principle #1Segmentation

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

This design achieves high surge current capacity with reduced material costs, minimizes the thermal sensitivity of the solder point, and ensures reliable, tension-free separation by utilizing the surge current to generate contact pressure, preventing solder thread formation and maintaining low permanent load on the solder joint.

Implementation Method 1

Overvoltage protection device with a mechanical disconnection device activated in the event of a thermal overload

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The closed position of the connection elements being secured by a solder or thermally detachable adhesive

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2047487B1Overvoltage protection device with mechanical arresting device activated in the case of thermal overload
Publication Date: 2010.05.26 DEHN SOHNE GMBH CO KG
  • EP2047487B1 patent drawingFigure 1
  • EP2047487B1 patent drawingFigure 2
  • EP2047487B1 patent drawingFigure 3

AI summary

The invention relates to an overvoltage protection device with a mechanical arresting device which is activated in the case of thermal overload, wherein said devices comprise connector elements which can be moved by means of a spring-loaded or pretensioned slider (4) from a closed position to a position in which current is interrupted or voltage is cut off, and wherein the closed position of the connector elements is maintained by a solder material or a thermally detachable adhesive. According to the invention, the connector elements consist of a pair of current-dividing metallic brackets (1, 1'), wherein the ends of said brackets (1, 1') which are directed toward the overvoltage protection element run parallel and include the corresponding contact lug (14) therebetween. The ends of the brackets (1, 1') which are turned away from the overvoltage protection element are connected to each other, enclosing a free space, and have a section (12) for external connector components or connector clamps. The slider (4) with pretensioned spring (2) is set in the free space, wherein the spring pretensioning is directed in the direction of the contact lug (14) of the overvoltage protection element. Furthermore, the slider (4) has a wedge shape and/or sections of the brackets have an inclined surface in order to generate a force component on the parallel ends of the brackets when the slider moves in such a way that said ends of the brackets can be moved away by the contact lug. The aforementioned solder or adhesive connection is formed in the area of the parallel ends of the brackets and the contact lug.