Circuit Breaker Subassembly Rotor Isolation
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Solution Overview
Problem
Existing multipole circuit breakers face issues with contact resistance variation due to deflection of cross pins and reduced dielectric strength between poles, leading to increased mechanism size and undesired energy distribution.
Innovation Solution
A circuit breaker subassembly with a multi-pole rotor assembly support that isolates the operating mechanism from contact arms, using a non-conductive one-piece rotor with blind holes and coaxial extension springs to reduce contact resistance variation and enhance dielectric strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cross pins are used to drive rotors for each phase, then the operating mechanism can be simplified, but deflection of cross pins causes contact depression variation and contact resistance variation between phases
Solution Approach 1:
The patent removes cross pins from the operating mechanism, extracting the source of deflection and contact depression variation. Each phase rotor is driven independently without shared cross pin components, eliminating the mechanical coupling that causes inconsistent contact closure across phases.
Solution Approach 2:
The operating mechanism is segmented into independent phase sections, with each phase having its own rotor drive path. This segmentation prevents the propagation of mechanical errors across phases and ensures consistent contact depression for each phase independently.
2Ease of operation
If openings are provided between separate poles for cross pins, then the operating mechanism can function, but dielectric strength between poles is reduced
Solution Approach 1:
The patent removes cross pins and the associated openings between poles, extracting the compromise between mechanism functionality and dielectric strength. Alternative drive mechanisms are used that do not require inter-pole openings, thereby maintaining full dielectric strength between all pole combinations.
3Use of energy by moving object
If spring size is increased to increase closing energy, then available energy to close contact arms increases, but mechanism size increases
Solution Approach 1:
The patent optimizes spring parameters and arrangement to achieve required closing energy without increasing overall mechanism size. This may involve using higher energy density spring materials, optimizing spring geometry, or arranging springs more efficiently within the existing mechanism envelope.
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 provides consistent contact closure, reduced contact resistance variation, and increased dielectric strength between poles, while maintaining a compact design by isolating the operating mechanism and using extension springs for enhanced closing energy.
Implementation Method 1
An amount of energy available to close the contact arms is typically related to forces exerted by springs included within an operating mechanism of the circuit breaker
Implementation Method 2
A rotor assembly for a multi-pole circuit breaker may be supported on a base of the circuit breaker in a manner that provides electrical isolation between phases of a multi-pole circuit breaker
Data Source
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AI summary
A circuit breaker subassembly (50) is disclosed. The subassembly includes a base (475), an operating mechanism (65), a one-piece non-conductive rotor (105) disposed within the base (475), and a plurality of sets of contact arms (190) supported by the rotor (105). The rotor (105) is disposed in operable connection with the operating mechanism (65) and includes a rotational degree of freedom relative to the base (475) with portions of the rotor (105) disposed between each set of the plurality of sets of contact arms (190) to define separation portions (450). The operating mechanism (65) includes a frame (310) disposed within the base (475), a cradle (340) in pivotal connection with the frame (310), an upper link (350) in pivotal connection with the cradle (340), and a lower link having a first end (410) and a second end (415), the first end (410) in pivotal connection with the upper link (350) and the second end (415) in pivotal connection with the rotor (105) at the separation portions (450).