Remote Circuit Breaker Racking Actuator for Arc Flash Safety
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Solution Overview
Problem
Modular skid frames used in harsh environments face challenges in minimizing damage during relocation and reducing the risk of arc flashes, which can result in injury or death, especially when handling circuit breakers in explosive or ignitable gas environments.
Innovation Solution
The modular skid frame design incorporates hook members for safe lifting and movement, coupling plates for secure joining of adjacent frames, and a remote actuating device for racking circuit breakers in and out without direct operator contact, along with dampening means to cushion transformers during orientation changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circuit breakers are manually racked in and out by operators, then the operation can be performed with simple mechanical means, but operators are exposed to arc flash hazards that can cause injury or death
Solution Approach 1:
A remote actuating device is introduced as an intermediary between the operator and the circuit breaker cradle. The actuator engages with the cradle and mechanically transfers force to rack the breaker in or out, allowing the operator to remain at a safe distance from arc flash hazards while still performing the racking operation
Solution Approach 2:
The manual mechanical racking operation is replaced with a remotely actuated mechanical system. The actuator can be positioned and operated remotely, substituting direct manual handling with an automated or remotely-controlled mechanical intervention that eliminates operator exposure to hazards
2Strength
If skid frames are moved without proper lifting mechanisms, then the structure remains simple, but significant damage can occur to the skid frame during relocation
Solution Approach 1:
Hook members are pre-installed on the skid frame structure at locations designed to bear the lifting loads. These hooks are positioned and sized in advance to handle the weight and distribution of the skid frame components, ensuring that when lifting is required, the structure is already prepared to support the loads without damage
Solution Approach 2:
Hook members serve as intermediaries between the external lifting equipment and the skid frame structure. Rather than directly attaching lifting equipment to the frame, the hooks provide dedicated attachment points that are structurally optimized for lifting, distributing loads appropriately and preventing damage to the frame during relocation
3Strength
If adjacent modular skid frames are joined without proper coupling mechanisms, then the assembly process is simpler, but shear loading between frames can compromise structural integrity
Solution Approach 1:
Coupling plates are provided that combine multiple functions: structural connection between frames, alignment features, and shear load resistance. By merging these functions into a single integrated component, the joint achieves high strength and structural integrity while maintaining relative simplicity in the coupling mechanism
Data Source
AI summary
Disclosed is a device for remotely racking a circuit breaker into and out of a circuit breaker cradle received within a circuit breaker module. The device comprises an actuator configured to rotate a breaker shaft in a first direction and an opposite second direction to rack the circuit breaker into and out of the circuit breaker cradle without the need for an operator to attend in the vicinity of the circuit breaker module.