Extension Handle Stopper for Motor Breaker Misoperation Prevention
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Solution Overview
Problem
Existing motor protection circuit breakers are prone to accidental switching from the ON state to the manual tripping state due to misoperation of the extension handle assembly, necessitating a solution to increase the required force for such transitions while maintaining the ability to switch to the fault tripping state.
Innovation Solution
An extension handle assembly with a stopper mechanism that provides a stopping force during manual tripping to increase the rotation force needed to switch from the ON state to the manual tripping state, and a biasing member to facilitate smooth transitions to the fault tripping state without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the extension handle assembly allows easy rotation from the first position to the second position, then the manual tripping operation is convenient, but accidental misoperation increases
Solution Approach 1:
The stopper is pre-positioned in the housing to abut against the handle during manual tripping, creating a preliminary mechanical barrier that requires additional force to overcome. This preliminary action prevents accidental activation while maintaining intentional tripping capability
Solution Approach 2:
The stopper provides a counteracting force that opposes the handle rotation during manual tripping. This preliminary anti-action creates a deliberate resistance that must be overcome, preventing unintended operation while allowing purposeful tripping when sufficient force is applied
2Reliability
If the stopper provides a stopping force during manual tripping, then accidental switches are reduced, but the force required for operation increases
Solution Approach 1:
The stopping force is applied locally and selectively - the stopper only engages during manual tripping operations (first position to second position) while remaining disengaged during fault tripping operations (first position to third position). This localized application increases force only where needed for safety without affecting normal fault tripping
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 effectively reduces accidental switching to the manual tripping state while ensuring seamless transitions to the fault tripping state, enhancing the reliability and safety of the circuit breaker operation.
Implementation Method 1
a stopper (13), pivotally installed in the housing (11), wherein the stopper is configured to abut against the handle (12) upon the handle (12) rotating from the first position to the second position
Implementation Method 2
further including a biasing member (15) connected between the stopper (13) and the housing (11), wherein the biasing member (15) is configured to push the stopper (13) away from a rotation path of the handle (12)
Data Source
Figure 1~2
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Figure 5~6
AI summary
An extension handle assembly for a motor protection circuit breaker and a motor protection circuit breaker. The extension handle assembly includes: a housing; a handle, installed to the housing; during a manual tripping period of the motor protection circuit breaker, the handle drives the knob to rotate from a first position to a second position, during a fault tripping of the motor protection circuit breaker, the knob drives the handle to rotate from the first position to a third position; a stopper, pivotally installed in the housing, the stopper is configured to abut against the handle upon the handle rotating from the first position to the second position during the manual tripping period of the motor protection circuit breaker, so as to provide a stopping force for a rotation of the handle to increase a force required for the rotation of the handle from the first position to the second position, and the stopper is configured not to abut against the handle upon the handle rotating from the first position to the third position during the fault tripping period of the motor protection circuit breaker, so as not to provide a stopping force for the rotation of the handle.