Electromagnetic Overcurrent Trip Core Layout for Compact Breakers
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Solution Overview
Problem
Existing overcurrent trip devices require larger external dimensions to compensate for reduced conductor volume, leading to increased device size.
Innovation Solution
The overcurrent trip device incorporates a stationary core enclosing the conductor with a movable core and guide plates, eliminating unnecessary space and optimizing electromagnetic force, while using a spring mechanism to adjust and stabilize the operating current value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal trip device is used for overcurrent protection, then it provides basic overcurrent protection function, but it cannot distinguish between overload current and short-circuit current leading to inappropriate tripping
Solution Approach 1:
The trip device is segmented into two independent functional modules: a thermal trip module with a bimetallic plate for overload protection, and an electromagnetic trip module with an electromagnet for short-circuit protection. Each module operates independently with its own tripping mechanism, allowing precise distinction between different fault types without requiring a complex integrated design.
Solution Approach 2:
The patent introduces a solenoid valve as an intermediary component that controls the communication between the electromagnetic trip module and the common trip mechanism. The solenoid valve acts as a gatekeeper, allowing the electromagnetic trip to activate the common mechanism only during short-circuit conditions, while preventing inappropriate activation during overload conditions.
2Reliability
If the electromagnetic trip device activates the common trip mechanism during overload, then the tripping function is triggered, but normal operation is interrupted causing unnecessary power outages
Solution Approach 1:
The solenoid valve is designed with dynamic control capability, allowing it to selectively open or close the communication path between the electromagnetic trip module and the common trip mechanism based on the nature of the fault. During overload conditions, the solenoid valve remains closed to prevent false tripping, while during short-circuit conditions, it opens to enable appropriate protection tripping.
3Reliability
If the thermal trip device takes long to respond to overcurrent, then it provides thermal protection, but it fails to provide rapid protection for short-circuit currents causing equipment damage
Solution Approach 1:
The patent merges the thermal trip module and electromagnetic trip module into a single integrated trip device housing. Both modules share common structural elements and the common trip mechanism, achieving rapid short-circuit protection and thermal protection functions in one unified device without requiring separate protection systems.
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
This configuration allows for a reduction in the size and weight of the overcurrent trip device and circuit breaker, maintaining stable operating current values and preventing variations.
Implementation Method 1
the solenoid valve responds to electromagnetic force to open or close
Implementation Method 2
the trip arm lever rotates counterclockwise due to electromagnetic attraction
Data Source
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AI summary
To obtain an overcurrent trip device which can realize a reduction in the size of the device and a circuit breaker using the same. An overcurrent trip device (100) includes a conductor (3) connected to a main circuit of a circuit breaker (200); a stationary core (1) which is formed so as to enclose the conductor (3) and one portion of which is opened; and a moving core (2) which is disposed in the opened position of the stationary core (1) with a magnetic gap (4) interposed between the moving core and the stationary core (1), is disposed so as to be movable by an electromagnetic force of when an overcurrent flows through the conductor (3), wherein the stationary core (1) is disposed in abutment with the conductor (3), and the moving core (2) is in contact with the conductor (3) when no overcurrent flows through the conductor (3) before in operation.