Split Core Slot Motor Assembly for Circuit Breakers
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Solution Overview
Problem
The assembly of narrow width channel slot motors in circuit breakers is challenging due to the need to deform the reverse loop conductor, which can lead to unreliable re-bending and stress on the conductor, affecting the integrity and performance of the electrical switching apparatus.
Innovation Solution
A split core slot motor assembly that engages coupling points between the first and second slot motor portions without deforming the reverse loop conductor, allowing for a U-shaped configuration that reduces stress and improves assembly, comprising a housing, separable contacts, an operating mechanism, and a power conductor with a split core slot motor formed by two portions that cooperate to create a base between the conductor and the reverse loop conductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a narrow width channel slot motor is assembled in a conventional loop shape, then the magnetic performance is improved, but the reverse loop conductor must be deformed which causes stress and unreliable re-bending
Solution Approach 1:
The slot motor is divided into two separate portions: a U-shaped portion and a base portion. The U-shaped portion can be assembled around the reverse loop conductor without deformation, and the base portion is separately attached to complete the narrow width channel configuration. This segmentation eliminates the need to deform the conductor while achieving the desired magnetic performance.
2Ease of manufacture
If the reverse loop conductor is deformed to accommodate a conventional slot motor, then the slot motor can be installed, but the conductor experiences stress and potential integrity issues
Solution Approach 1:
By dividing the slot motor into a U-shaped portion and a base portion, the assembly process no longer requires deforming the reverse loop conductor. The U-shaped portion fits around the conductor in its natural state, preserving conductor strength and integrity while still enabling slot motor installation.
3Manufacturing precision
If a conventional loop-shaped slot motor is used, then the magnetic performance is adequate, but the manufacturing complexity increases due to conductor deformation requirements
Solution Approach 1:
The slot motor is segmented into a U-shaped portion that provides the magnetic path and a base portion that completes the narrow width channel. This segmentation simplifies the assembly process by eliminating conductor deformation while maintaining the precise magnetic performance required for effective arc quenching and current limiting.
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 split core slot motor design enhances short circuit interruption performance, reduces the probability of dielectric breakdown, and improves economics by eliminating the need for conductor deformation, while maintaining magnetic performance comparable to conventional slot motors during critical opening phases.
Implementation Method 1
The electrical current interacts electromagnetically with the slot motor to induce a magnetic field in the magnetic material of the slot motor
Implementation Method 2
which, in turns, interacts with the separating contacts and the movable contact arm to accelerate the contact opening process
Data Source
AI summary
A circuit breaker includes a housing, separable contacts, an operating mechanism structured to open and close the separable contacts, a power conductor comprising a first conductor and a second reverse loop conductor, the second reverse loop conductor carrying one of the separable contacts; and a split core slot motor. The split core slot motor comprises a first slot motor portion having a number of coupling points, and a second slot motor portion having a number of corresponding coupling points. The coupling points of the first slot motor portion engage the corresponding coupling points of the second slot motor portion to form the split core slot motor. Both of the slot motor portions cooperate to form a base of the split core slot motor. The base is disposed between the first conductor and the second reverse loop conductor.