High Voltage Folding Disconnect Switch Locking Mechanism
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Solution Overview
Problem
High voltage folding disconnect switches often malfunction due to premature straightening of the blade when encountering ice build-up, leading to misalignment of the break jaw contact pin with the notch in the break jaw contacts, requiring repeated opening and refolding of the switch.
Innovation Solution
A second return spring and trigger lever-locking bar mechanism are introduced to lock the switch blade from straightening until ice build-up is chopped away, ensuring proper alignment of the break jaw contact pin with the notch, and a cam slot mechanism allows the blade to straighten only when the switch is fully closed, ensuring proper contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the switch blade is allowed to fold freely with only a joint spring, then the blade can open and close smoothly, but the blade prematurely straightens when encountering ice build-up, causing misalignment
Solution Approach 1:
The locking mechanism applies a preliminary restraining force against the blade's tendency to straighten prematurely. The lock engages with the cam slot to prevent straightening motion until the blade reaches the correct position, counteracting the harmful effect of ice build-up that causes premature straightening and misalignment.
Solution Approach 2:
The blade is held in the folded position by the locking mechanism until the closing operation begins. The lock releases at the appropriate moment to allow straightening, ensuring the blade is properly positioned before contact is made, thereby preventing misalignment caused by ice interference.
2Reliability
If a locking mechanism is added to prevent premature straightening, then alignment reliability improves, but device complexity increases
Solution Approach 1:
The locking mechanism is integrated with the existing blade structure, using the same pivot points and mounting locations. The lock, cam slot, and trigger lever are combined into a unified assembly that works together with the joint spring and blade geometry, avoiding the need for separate independent components and reducing overall complexity.
Solution Approach 2:
The locking mechanism serves multiple functions: it prevents premature straightening, ensures proper alignment, and can be released by the trigger lever. The cam slot both locks the blade in position and guides its motion during release, combining locking and guiding functions in a single feature.
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
Prevents premature straightening of the switch blade during ice build-up, allowing for effective chopping of ice and proper alignment of the break jaw contact pin, thereby eliminating malfunctions and ensuring reliable electrical closure.
Implementation Method 1
The joint spring is known from the prior art, for example, side break switch, and keeps the blade folded as the switch blade opens and as the switch begins to close
Implementation Method 2
the blade must be closed rapidly to impart a chopping action to break through the ice
Data Source
AI summary
A high voltage folding disconnect switch including a folding switch blade that folds as it opens or closes and which is divided into a fixed blade portion attached to a rotating insulator and a folded blade portion having an electric contact surface engaging a break jaw contact surface. A trigger lever-locking bar is mounted to the fixed blade portion. The trigger lever-locking bar includes a trigger finger for contacting a trigger surface mounted on a stationary insulator. The trigger lever-locking bar has a cam slot for interaction with a cam follower pin that locks the movement of the folding blade so that premature straightening of the blade is prevented until any ice build-up on the switch has been alleviated.