Load Break Switch Vacuum Interrupter Pressure Differential
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Solution Overview
Problem
Existing medium voltage load break switches using vacuum interrupters face inefficiencies in current commutation and disconnection processes, requiring improved mechanisms for stable and efficient electrical switching operations.
Innovation Solution
A medium voltage load break switch design featuring a rotating knife and lever system, where the knife transitions through various configurations to manage current flow and interrupter operation, utilizing a vacuum interrupter with a fixed and movable contact, and a lever that rotates to achieve stable positions for both closed and open configurations, leveraging pressure differentials for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum interrupter is used in a load break switch, then electrical disconnection occurs within the vacuum interrupter, but the mechanism requires complex lever systems and continuous force application for stable operation
Solution Approach 1:
The vacuum interrupter utilizes the pressure differential between the vacuum interior and atmospheric exterior to generate self-actuating force. The atmospheric pressure pushes the movable contact against the fixed contact during closing, and the vacuum pressure assists during opening, eliminating the need for continuous external force application and complex lever mechanisms.
Solution Approach 2:
The patent extracts the force generation function from complex external lever systems and relocates it to the vacuum interrupter itself. By utilizing the inherent pressure differential of the vacuum environment, the system generates its own operating forces, simplifying the overall mechanism.
2Ease of operation
If a lever system is used to actuate the vacuum interrupter, then switching operation is achieved, but stable positions require continuous force application
Solution Approach 1:
The vacuum interrupter system uses the pressure differential as a self-sustaining force source. During closing operation, atmospheric pressure pushes the movable contact onto the fixed contact. During opening, the vacuum pressure differential assists the opening motion. This self-service mechanism eliminates the need for continuous external force application to maintain stable positions.
Solution Approach 2:
The pressure differential acts as a counterbalancing force that naturally supports the movable contact in both open and closed positions. The atmospheric pressure counteracts the spring force during closing, while the vacuum pressure assists during opening, creating a balanced system that maintains positions without continuous force.
3Productivity
If the knife rotates about a pivot point to connect and disconnect contacts, then switching function is achieved, but current commutation efficiency is reduced
Solution Approach 1:
The atmospheric pressure force is already present and acting on the movable contact before the switching operation begins. During closing, this pre-existing atmospheric pressure immediately assists the contact engagement, enabling faster and more efficient current commutation without requiring additional force during the critical switching moment.
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 new design provides a stable and efficient mechanism for current commutation and interruption, allowing for seamless transitions between closed, commutation, and open configurations without requiring continuous force application, driven by the pressure differential within the vacuum interrupter, enhancing the operational reliability of the load break switch.
Implementation Method 1
leveraged pressure differentials for operation
Data Source
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AI summary
The invention relates to a medium voltage load break switch. The load break switch comprises a main contact and a knife. The knife is configured to rotate about a pivot point to connect to and be in contact with the main contact and to rotate about the pivot point to disconnect from and be spaced from the main contact. The load break switch also comprises a vacuum interrupter (10). The vacuum interrupter has a fixed contact (11) and a moveable contact (12) that are in a housing of the vacuum interrupter. The main contact is in electrical connection with the fixed contact of the vacuum interrupter. The load break switch also has a lever (20). The lever is configured to rotate about a rotation point (21) of the lever. The main contact is spaced from the lever. A shaft of the moveable contact is aligned along an axis of the vacuum interrupter, and the shaft of the moveable contact is linked to the lever. In a closed configuration of the load break switch the knife is in contact with the main contact and spaced from the lever. In a closed configuration the lever is at a first rotational orientation and the rotation point of the lever is at a first distance from the fixed contact measured in a direction parallel to the axis of the vacuum interrupter and the moveable contact is in contact with the fixed contact, and current can flow through the main contact directly to the knife. Rotation of the knife about its pivot point in a first rotational direction transitions the switch from the closed configuration to a commutation configuration. In the commutation configuration the knife is in contact with the lever and in contact with the main contact, and current can flow through the main contact directly to the knife and flow through the main contact and through the vacuum interrupter to the knife. Rotation of the knife about its pivot point in the first rotational direction transitions the switch from the commutation configuration to an opened configuration. In the opened configuration the knife is spaced from the main contact and spaced from the lever or in contact with the lever. In the opened configuration the lever is in a second rotational orientation and the rotation point of the lever is at a second distance from the fixed contact measured in the direction parallel to the axis of the vacuum interrupter that is greater than the first distance and the moveable contact is spaced from the fixed contact.