Circuit Breaker Racking Stop Mechanism
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Solution Overview
Problem
In medium voltage circuit breakers, excessive racking-in can cause damage to the breaker and its mechanism, leading to potential equipment damage and safety hazards due to accidental over-rotation during the racking-in process.
Innovation Solution
A mechanism featuring a threaded connecting rod with a non-threaded portion that prevents further rotation once fully engaged, ensuring the circuit breaker is securely stopped from over-racking into the cubicle, using a capture block with internal screw threads and a spring mechanism for secure alignment and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the operator continues rotating the racking-in rod after the circuit breaker is fully engaged, then the rod can be easily manipulated, but the circuit breaker may be over-racked into the case causing damage to components
Solution Approach 1:
The patent applies preliminary anti-action by incorporating a non-threaded portion on the racking-in rod that prevents further rotation after the circuit breaker is fully engaged. This preliminary mechanical stop counteracts the potential harmful action of over-rotation before damage can occur to the electrical contacts or case components
Solution Approach 2:
The non-threaded portion of the rod acts as an intermediary element between the threaded portion and the circuit breaker body. It serves as a mediator that transmits the racking force during engagement but then blocks further transmission of rotational force, preventing direct contact and potential damage between the rod and case components
2Device complexity
If no external stopping devices are used, then the design is simpler and more reliable, but precise control of the racking-in limit is difficult to achieve
Solution Approach 1:
The patent applies self-service by designing the racking mechanism to automatically limit its own travel through the non-threaded portion of the rod. The mechanism serves itself by incorporating the stop function directly into the rod structure, eliminating the need for external stopping devices while maintaining precise control of the racking-in limit
Solution Approach 2:
The patent merges the racking function and the stopping function into a single integrated component - the racking-in rod. By combining these functions, the design achieves precision without adding separate stopping devices, maintaining simplicity while ensuring accurate limitation of racking travel
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 over-racking of the circuit breaker, thereby protecting the equipment and reducing the risk of damage or injury by ensuring precise engagement and preventing accidental over-rotation.
Implementation Method 1
a spring mechanism for secure alignment and operation
Data Source
AI summary
A racked in and out circuit breaker for a cubical housing of electrical switchgear has a back to front, threaded rod mechanism and, at the rear of the cubical a stationary and interior threaded bolt is provided so that when the rod is turned the circuit breaker is mechanically pulled into the cubical and, if turned oppositely, causes the circuit breaker to move out of the cubical housing. A non-threaded section of the rod cooperates with the same bolt so that when it is within the threads of the bolt, further effort at rotating the rod prevents further rearward movement of the circuit breaker.