Circuit Breaker Magnetic Trip Device with Manual Reset Latch
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Solution Overview
Problem
Conventional magnetic trip devices for circuit breakers lack a means to maintain fault information indication until the cause of an accident is removed and reset, posing a risk of electrical safety accidents when the circuit breaker is returned to the ON position before the fault is resolved.
Innovation Solution
A magnetic trip device with an actuator coil part, output plate, micro switch, switch driving lever mechanism, automatic reset mechanism, and driving lever latch that maintains a trip indication state after a trip operation, and a manual reset lever to forcibly release this state, ensuring the circuit breaker remains in a trip indication until the fault is addressed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an automatic reset mechanism is provided to reset the plunger after trip operation, then the circuit breaker can be quickly restored to operational position, but the fault indication is lost and the circuit breaker may be operated before the fault is resolved
Solution Approach 1:
The reset function is segmented into two independent parts: (1) automatic reset of the plunger position via the automatic reset mechanism, and (2) manual reset of the fault indication via the driving lever latch. This allows the plunger to be automatically reset for quick restoration while the fault indication remains preserved until manually cleared, resolving the contradiction between productivity and safety.
Solution Approach 2:
The driving lever latch acts as an intermediary mechanism between the automatic reset mechanism and the micro switch. It decouples the automatic plunger reset from the fault indication reset, allowing the fault signal to be maintained independently until the user manually clears it, thus preventing premature operation while maintaining productivity.
2Device complexity
If the plunger is automatically reset to initial position after trip operation, then the device complexity is reduced, but the ability to maintain fault information is lost
Solution Approach 1:
The reset function is segmented into two independent parts: (1) automatic reset of the plunger position via the automatic reset mechanism, and (2) manual reset of the fault indication via the driving lever latch. This allows the plunger to be automatically reset for quick restoration while the fault indication remains preserved until manually cleared, resolving the contradiction between productivity and safety.
Solution Approach 2:
The driving lever latch is designed to automatically engage and maintain the fault indication state immediately after trip operation, before the user has a chance to reset it. This preliminary action of preserving fault information automatically ensures that even though the plunger is automatically reset, the fault information is not lost.
3Reliability
If a driving lever latch mechanism is added to maintain trip indication, then safety is improved by preventing premature operation, but the device complexity increases
Solution Approach 1:
The driving lever latch mechanism is merged with the existing switch driving lever mechanism, sharing common components such as the rotating shaft and lever structure. This integration minimizes the increase in device complexity while achieving the safety function of maintaining fault indication until manual reset.
Solution Approach 2:
The driving lever latch is designed to perform multiple functions: (1) maintain the fault indication state after trip operation, (2) prevent premature reset of the micro switch, and (3) be manually resettable to clear the fault indication. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
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
Prevents electrical safety accidents by maintaining a trip indication state until the fault is resolved, allowing safe operation by ensuring the fault cause is removed before returning the circuit breaker to the ON position.
Implementation Method 1
an actuator coil part that has a plunger configured to move to an advanced position or a retracted position according to the magnetization or demagnetization of a coil
Implementation Method 2
an actuator coil part that has a plunger configured to move to an advanced position or a retracted position according to the magnetization or demagnetization of a coil
Data Source
Figure 1
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AI summary
The magnetic trip device for the circuit breaker of the invention comprises an actuator coil part having a plunger; an output plate configured to rotate in a first direction; a micro switch configured to output an electrical signal indicating a state of the circuit breaker; a switch driving lever mechanism configured to rotate to a first position for pressing the micro switch and a second position for releasing the micro switch; a driving lever bias spring configured to elastically bias the switch driving lever mechanism to rotate to the second position; an automatic reset mechanism configured to press the plunger to the retracted position; and a driving lever latch configured to rotate to a restraining position for preventing the switch driving lever mechanism from rotating to the first position, and a release position for allowing the switch driving lever mechanism to rotate to the first position.