Shunt Assembly Constraint Elements Torque Conversion

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Solution Overview

Problem

Low-voltage circuit breakers experience inefficient translation of magnetic repulsion force from shunts into torque for movable contact arms, resulting in suboptimal blow-on performance and fault current withstand.

Innovation Solution

Incorporation of constraint elements proximate bends in shunt assemblies to constrain movement and translate magnetic repulsion force into torque for movable contact arms, utilizing restraint members to impose forces on shunts and direct energy effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible conductors (shunts) are used to connect the movable contact assembly to the rigid conductor, then the circuit breaker can accommodate motion during trip conditions, but the magnetic repulsion force is not efficiently translated into torque of the movable contact arms

Engineering Contradiction:
Improvemotion accommodationVSAvoidtorque generation
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

A constraint element is introduced as an intermediary component between the flexible conductor and the movable contact arm. This constraint element mediates the interaction by providing a pivot point that converts the linear magnetic repulsion force into rotational torque, enabling both motion accommodation and effective force transmission

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible conductor is designed with specific geometric parameters including bends at predetermined locations. These parameter changes in the conductor's shape allow it to accommodate motion while the constraint element leverages these bends to convert linear force into rotational torque through lever arm mechanics

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the shunts are allowed to move freely to accommodate contact arm motion, then adaptability is improved, but blow-on performance and fault current withstand capability deteriorate

Engineering Contradiction:
Improvecontact arm motionVSAvoidfault current withstand
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The constraint element serves as a mediator that controls and guides the motion of the flexible conductor. It allows necessary motion for contact arm movement while preventing excessive or uncontrolled motion that would reduce blow-on performance and fault current withstand capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible conductor incorporates bends at specific locations with predetermined radii and angles. These parameter changes create controlled movement paths that accommodate contact arm motion while maintaining sufficient mechanical coupling to transmit magnetic repulsion force effectively for reliable fault current interruption

Inventive Principle:
Principle #35Parameter changes

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

Enhances the ability of circuit breakers to withstand high fault currents by efficiently converting magnetic repulsion force into torque, improving blow-on performance and maintaining electrical contact.

Implementation Method 1

In response to the fault current, the at least one flexible conductive element is subject to a magnetic repulsion force which tends to straighten the bends of the flexible conductive element

Methodology Applied
Scientific EffectMagnetic repulsion force: Lorentz Force

Implementation Method 2

translate the magnetic repulsion force into a corresponding torque of the movable contact arms of the movable contact assembly

Methodology Applied
Scientific EffectTorque: Torque

Data Source

PatentEP1968093B1Electrical switching apparatus, and conductor assembly and shunt assembly therefor
Publication Date: 2016.03.02 EATON CORP
  • EP1968093B1 patent drawingFigure 1
  • EP1968093B1 patent drawingFigure 2~3C
  • EP1968093B1 patent drawingFigure 4A~4B

AI summary

A shunt assembly is provided for an electrical switching apparatus including a conductor assembly having a load conductor and a movable contact assembly with a number of movable contact arms. The movable contact assembly is movable in response to a fault current. The shunt assembly includes a number of flexible conductive elements each having a first end electrically connected to the load conductor, a second end electrically connected to a corresponding one of the movable contact arms, and a number of bends disposed between the first and second ends. At least one constraint element is disposed proximate a corresponding one of the bends ' and constrains movement of the flexible conductive element in response to the fault current, thereby translating the magnetic repulsion force associated with the fault current into a corresponding torque of the movable contact arms of the movable contact assembly.