Gas Insulated Switchgear Cam Mechanism for Fast Breaking
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Solution Overview
Problem
Existing gas insulated switchgear faces challenges in achieving fast breaking operations without increasing the actuator's volume, as it requires high actuating power and quick separation of contact arms, which is difficult to achieve with existing torque transmission and movement characteristics.
Innovation Solution
The design incorporates a cam mechanism with first and second cam surfaces that provide different movement accelerations and distances, allowing for rapid initial separation and extended distance separation at lower speeds, enabling adjustable movement characteristics of the movable contact arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a large capacity spring is used to increase actuating power, then breaking speed is improved, but the volume of the actuator increases
Solution Approach 1:
The patent applies dynamics by making the torque transmission characteristics variable through the cam mechanism. The cam profile is designed to provide high torque at the initial stage of breaking operation when maximum acceleration is needed, and then gradually reduce torque as the movable contact arm approaches the breaking position. This dynamic torque adjustment allows fast breaking operation without requiring a large capacity spring throughout the entire motion range, thus reducing actuator volume while maintaining breaking speed.
2Speed
If maximum torque is transmitted at the initial stage of breaking operation, then breaking acceleration is improved, but the duration of maximum torque transmission is too short
Solution Approach 1:
The patent changes the torque parameter over time through the cam mechanism design. The cam profile is specifically shaped to maintain maximum torque transmission for an extended duration during the initial stage of breaking operation. As the movable contact arm moves toward the breaking position, the cam gradually reduces the torque transmission. This parameter change approach allows sufficient acceleration time without requiring the movable contact arm to travel an excessively long distance, thereby resolving the contradiction between acceleration duration and breaking speed.
3Loss of time
If the movable contact arm is separated quickly from the stationary contact arm, then fault current interruption time is reduced, but the actuating power requirement increases
Solution Approach 1:
The patent uses dynamics by implementing a time-varying torque transmission mechanism through the cam. During the initial stage of breaking operation when the movable contact arm needs to overcome friction and arc pressure, the cam provides maximum torque to achieve rapid separation and reduce fault current interruption time. As the separation progresses and less force is required, the cam gradually reduces torque transmission. This dynamic power adjustment achieves fast breaking operation without requiring continuously high actuating power, thus reducing the actuator capacity and volume.
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 faster breaking operation with the same actuating power, reducing the time of maximum torque transmission and minimizing torque decrement, thereby enhancing the breaking speed and maintaining sufficient insulating distance.
Implementation Method 1
a cam (120) reciprocating between a closing position and an opening position to move the movable contact arm (160)
Implementation Method 2
a large capacity spring needs to be used
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A gas insulated switchgear (100) includes: an enclosure (102); a stationary contact arm (170) fixedly installed within the enclosure (102); a movable contact arm (160) installed to be moved within the enclosure (102) such that it is brought into contact with or separated from the stationary contact arm (170); a cam (120) reciprocating between closing and opening positions to move the movable contact arm (160); and an actuator (200) moving the cam (120), wherein the cam (120) includes first and second cam surfaces (124a, 124b) , and when the cam (120) moves to an opening position by the actuator (200), movement acceleration of the movable contact arm (160) by the first cam surface (124a) is greater than movement acceleration by the second cam surface (124b) and a movement distance of the movable contact arm (160) by the first cam surface (124a) is smaller than a movement distance by the second cam surface (124b).