Vacuum Interrupter Windmill Electrode Leakage Current
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Solution Overview
Problem
In vacuum interrupters with windmill-shaped electrodes, leakage current flowing to reinforcing plates and spacers reduces the arc drive force, leading to decreased interruption performance and increased size and weight due to larger electrode diameters.
Innovation Solution
Incorporating support members with high electric resistance, such as cylindrical and disk-shaped portions, between the electrode rods and windmill-shaped electrodes to inhibit leakage current and maintain arc drive force without increasing the device's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reinforcing plates and spacers are incorporated to reinforce windmill-shaped electrodes, then electrode strength and prevention of metal spatter scattering are improved, but leakage current increases which reduces arc drive force and interruption performance
Solution Approach 1:
A magnetic field generating portion is introduced as an intermediary component between the electrode rod and the windmill-shaped electrode. This intermediary generates a magnetic field that directly acts on the arc to provide arc drive force, while the reinforcing plate and spacer are positioned to minimize their impact on the current path. The magnetic field generating portion serves as a mediator that restores the arc drive force that was reduced by the leakage current to the reinforcing structures.
2Reliability
If diameter of windmill-shaped electrode is increased to maintain arc drive force, then arc drive force is improved, but device size and weight increase
Solution Approach 1:
Instead of changing the physical dimension (diameter) of the windmill-shaped electrode to increase arc drive force, the invention changes the physical parameter by introducing a magnetic field. The magnetic field generating portion creates a magnetic field whose strength and distribution can be optimized to provide adequate arc drive force without requiring an increase in electrode diameter, thereby avoiding the associated increase in device size and weight.
3Reliability
If diameter of windmill-shaped electrode is increased to maintain arc drive force, then arc drive force is improved, but device size increases
Solution Approach 1:
The invention transitions from a geometric solution (increasing electrode diameter) to a field-based solution (introducing magnetic field). The magnetic field generating portion produces a magnetic field that extends through the interruption space, providing arc drive force without requiring additional physical volume from enlarged electrodes. This parameter change from spatial dimension to field intensity allows maintaining arc drive force while controlling device size.
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 reinforces the windmill-shaped electrodes, prevents metal spatter scattering, and enhances interruption performance by maintaining arc drive force without increasing the vacuum interrupter's size or weight.
Implementation Method 1
the current density of current flowing through the windmill-shaped electrode is reduced, so that the magnetic flux density of a generated magnetic field is also reduced
Implementation Method 2
the arc drive force proportional to the magnetic flux density is also reduced
Implementation Method 3
in a case where current is interrupted, the fixed-side electrode and the movable-side electrode are opened, whereby arc occurs
Data Source
AI summary
A vacuum interrupter includes: an insulation cylinder; a fixed-side flange; a movable-side flange; a fixed-side electrode rod fixed to the fixed-side flange at one end and having a fixed-side electrode fitting shaft on a fixed-side end surface at another end; a movable-side electrode rod connected to the movable-side flange via a bellows at one end and having a movable-side electrode fitting shaft on a movable-side end surface at another end; a fixed-side windmill-shaped electrode fixed to the fixed-side electrode fitting shaft; and a movable-side windmill-shaped electrode fixed to the movable-side electrode fitting shaft. A fixed-side support member having a fixed-side spacer portion and a fixed-side planar portion is provided between the fixed-side end surface and the fixed-side windmill-shaped electrode, and a movable-side support member having a movable-side spacer portion and a movable-side planar portion is provided between the movable-side end surface and the movable-side windmill-shaped electrode.