Short-Circuiting Electrode Gap Control Across Current Zero Crossings
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Solution Overview
Problem
Existing short-circuiting devices in vacuumized chambers face challenges in maintaining current flow during current zero crossings, leading to potential interruption, especially in DC circuit breakers, while avoiding high contact forces.
Innovation Solution
A short-circuiting device with a movable electrode that moves past a second extended position to slightly touch a stationary electrode, triggered by a circuit that applies a voltage exceeding the gap breakdown voltage, using a Thomson actuator mechanism to control the movement and current flow, ensuring current continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable electrode is moved to an optimized gap position and triggered, then current flow can be controlled, but current interruption occurs at current zero crossings
Solution Approach 1:
The movable electrode is pre-positioned at the optimized gap position before triggering, allowing the current to continue flowing during and after zero crossings without interruption. This preliminary positioning ensures that when the current is triggered, the electrode is already in the correct position to maintain continuous current flow.
2Reliability
If the movable electrode moves towards the stationary electrode, then current flow is maintained, but high contact making forces occur
Solution Approach 1:
The gap distance between the movable and stationary electrodes is changed from a small optimized gap position to a larger distance during operation. By moving the movable electrode away from the stationary electrode after triggering, the contact making force is reduced while maintaining current flow continuity through the extended gap position.
3Reliability
If the movable electrode slightly touches the stationary electrode, then current flow is ensured, but mechanical wear increases
Solution Approach 1:
The rod acts as an intermediary mechanical element between the movable electrode and the actuating mechanism. It allows the movable electrode to achieve the slight touch with the stationary electrode for current flow assurance while the rod absorbs and distributes the mechanical stress, reducing direct wear on the electrode materials.
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
Ensures continuous current flow during and after zero crossings, reduces mechanical wear, and provides high voltage withstand capability, robustness against transients, and fast operation, combining the speed of a spark gap with the endurance of a mechanical switch.
Implementation Method 1
the triggering circuit is configured to apply a trigger voltage between the electrodes exceeding a gap breakdown voltage
Implementation Method 2
the actuating mechanism is a Thomson coil of the Thomson actuator
Data Source
Figure 1~2
Figure 3~4
AI summary
A short-circuiting device (14) comprises a triggering circuit (16), an actuating element (30), a stationary electrode (20) and a moveable electrode (22), where the actuating element (30) is moveable between a first retracted position and a first extended position and joined to the moveable electrode (22) for being moved between a corresponding second retracted position, where there is gap of a first distance between the moveable and stationary electrodes (22, 20), and a second extended position, where the gap has a second lower distance, the triggering circuit (16) being configured to trigger a current to start to flow between the electrodes (20, 22) after the actuating element (30) has been actuated to move from the first retracted position and before reaching the first extended position and the current continues to flow in the gap after a first zero crossing and at least until a second zero-crossing.