Overcurrent Tripping Device Lever Mechanism
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Solution Overview
Problem
Existing overcurrent tripping devices are large in size and do not effectively shorten the tripping operation time for fault currents, as increasing the electromagnet core volume to reduce magnetic saturation results in increased device size and mass.
Innovation Solution
An overcurrent tripping device with a fixed core and movable core configuration that reduces magnetic saturation by using a stacked core structure and a lever mechanism to transmit the spring load force, allowing for a compact design and rapid tripping operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the volume of the electromagnet core is increased to reduce magnetic saturation, then the tripping operation time is shortened, but the outer shape and mass of the overcurrent tripping device increase
Solution Approach 1:
The rod is positioned to penetrate inside the fixed core, and the lever is arranged within the space defined by the fixed core and other components. This nesting arrangement allows the tripping mechanism components to occupy the same spatial envelope as the electromagnet core, eliminating the need for additional external space and thereby reducing the overall device size while maintaining the required core volume for rapid tripping
Solution Approach 2:
The fixed core is designed with a partially open structure that obliquely cuts the magnetic field, creating a three-dimensional magnetic path that optimizes magnetic flux distribution. This dimensional optimization allows the magnetic field to be effectively utilized within a compact volume, reducing magnetic saturation without increasing the overall device size
2Loss of time
If the volume of the electromagnet core is increased to reduce magnetic saturation, then the tripping operation time is shortened, but the mass of the overcurrent tripping device increases
Solution Approach 1:
The rod penetrates inside the fixed core and the lever is positioned within the device envelope, nesting the tripping mechanism components within the space already occupied by the electromagnet assembly. This eliminates the need for additional external components and reduces overall device mass while maintaining sufficient core volume for rapid tripping response
Solution Approach 2:
The rod serves dual functions as both a structural support element and a linkage component that transmits motion from the movable core to the tripping mechanism. The lever similarly combines structural and functional roles, reducing the total component count and device mass while maintaining the required tripping performance
3Reliability
If the mechanism to actuate the tripping mechanism is provided outside the electromagnet, then the tripping operation is effective, but the size of the overcurrent tripping device is increased
Solution Approach 1:
The rod penetrates the fixed core and the lever is positioned within the device envelope, nesting the tripping mechanism components within the space already occupied by the electromagnet assembly. This eliminates the need for additional external components and reduces overall device size while maintaining effective tripping operation
Solution Approach 2:
The rod and lever are integrated into the electromagnet assembly as unified structural components. The rod serves as both a support structure and a motion transmission linkage, while the lever combines structural and actuating functions. This merging of functions reduces component count and device size while maintaining tripping effectiveness
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 enables a reduction in the size of the overcurrent tripping device while shortening the tripping operation time for fault currents, achieving faster fault response without increasing the device's outer shape or mass.
Implementation Method 1
when an overcurrent flows through a conductor penetrating the center of the electromagnet, a magnetic flux is generated in the electromagnet
Implementation Method 2
a movable core forming the electromagnet is attracted upward
Implementation Method 3
a return spring for setting a current scale value (current prescribed value to start tripping operation) of the tripping device
Implementation Method 4
a lever connected at one end thereof to the rod, connected at another end thereof to a spring provided outside the fixed core, and configured to rotate about a fulcrum provided between respective connection portions and transmit a load force of the spring to the movable core
Data Source
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AI summary
An overcurrent tripping device (100) includes: a conductor (3); a fixed core (1) surrounding the conductor (3) and being partially open; a movable core (2) having a magnetic gap at a position where the fixed core (1) is open, and movably disposed; a rod (5) penetrating an inside of the fixed core (1), linked to a tripping mechanism at an end projecting to the outside, and fixed to the movable core (2) in a bar shape; and a lever (8) connected at one end thereof to the rod (5), connected at another end thereof to a spring (9) provided outside the fixed core (1), and configured to rotate about a fulcrum and transmit a load force of the spring (9) to the movable core (2). The fixed core (1) has a gap perpendicular to a direction in which the conductor (3) extends, and, in the gap, a plate-shaped fixed core guide (6) having a groove (6c) is fixed and the lever (8) is disposed. The movable core (2) has a gap perpendicular to the direction in which the conductor (3) extends, and a plate-shaped movable core guide (7) which is partially interposed in the groove (6c) and slides is fixed in the gap.