Power Capacitor Protective Device with Removable Barrier

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Solution Overview

Problem

Existing power capacitors face issues with destructive pressure and overcurrent protection mechanisms that prevent their reuse after activation, leading to unnecessary capacitor failure even if electrical parameters meet technical requirements.

Innovation Solution

A power capacitor with a non-destructive pressure and overcurrent protective device featuring a flexible, axially deformable diaphragm and a fuse connected in series, which includes a removable barrier to release gas from an air chamber, allowing for capacitor reactivation by reconnecting the disconnecting system after pressure relief.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hermetic cover is used to seal the protective device, then the protection against external influences is improved, but the membrane cannot properly activate due to pressure equalization

Engineering Contradiction:
Improveprotection reliabilityVSAvoidmembrane activation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The hermetic cover is segmented into a fixed portion and a movable portion. The movable portion can be displaced by the membrane when it deforms under pressure, allowing the membrane to properly activate the protection mechanism while still maintaining hermetic sealing when in the normal position.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a deformable surface with breakaway wire is used for pressure protection, then the capacitor is protected against uncontrolled explosion, but the capacitor cannot be reused after protection activation

Engineering Contradiction:
Improveexplosion protectionVSAvoidcapacitor reusability
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

A fuse is introduced as an intermediary element between the membrane and the capacitor circuit. The fuse can be replaced after activation, allowing the capacitor itself to be reused. The fuse acts as a sacrificial component that protects the capacitor while maintaining the possibility of capacitor reusability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective device transitions from a static, destructive mechanism to a dynamic, restorable system. The movable cover portion and replaceable fuse allow the protection mechanism to be reset and reused, transforming the capacitor from a single-use protected state to a multi-use operational state.

Inventive Principle:
Principle #15Dynamics

3Reliability

If gas accumulation chamber is sealed, then pressure protection is maintained, but gas pressure cannot be released to allow capacitor reactivation

Engineering Contradiction:
Improvepressure protectionVSAvoidcapacitor reactivation
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The cover portion transitions from a fixed sealed state to a movable state that allows gas release. When the membrane deforms under pressure, it displaces the cover portion, opening a passage for gas to escape from the accumulation chamber, enabling capacitor reactivation while maintaining pressure protection during normal operation.

Inventive Principle:
Principle #15Dynamics

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

Enables the capacitor to be safely disconnected and potentially reused if parameters meet technical requirements, reducing unnecessary failures and extending operational life.

Implementation Method 1

The deformable surface, deforming under increased gas pressure, tears the breakaway wire or activates a snap-action mechanism

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

a flexible, axially deformable diaphragm and a fuse connected in series

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The breakaway wire is usually a constricted electric conductor, sometimes containing a fuse element or a fuse connected in series

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 4

The fuse element or the fuse also function as overcurrent protection

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 5

a small arc is formed, leading to the evaporation of a metallic coating around breakdown and the insulation regeneration

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 6

in the space under the flexible, axially deformable diaphragm is formed an air chamber

Methodology Applied
Scientific EffectGas accumulation:

Data Source

PatentEP3021337B1Power capacitor with a protective device
Publication Date: 2020.06.03 ZENEX SP ZOO
  • EP3021337B1 patent drawingFigure 1
  • EP3021337B1 patent drawingFigure 2
  • EP3021337B1 patent drawingFigure 3

AI summary

Power capacitor with a protective device, with at least one winding and a pressure and overcurrent protective device, comprising a flexible, axially deformable diaphragm and a fuse connected in series to the circuit of one of the electrodes of the winding, located in a rigid housing and sealed with resin, characterized in that inside the body of the protective device there is a circular, flexible, axially deformable diaphragm (4), fixedly built in a cylindrical portion of the body (3) of the protective device on the side of the winding, forming an air chamber (14) from the side of the winding, wherein in the side surface of the cylindrical body portion there is a cylinder projection forming an open channel (10) along the side surface, from the side of the air chamber (14), dosed with a removable barrier (13), over which a tube (11) coaxial with the channel under the barrier is built.