Front-Access Bus Connector Frame Assembly for Switchgear Maintenance
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Solution Overview
Problem
High voltages and heat in draw out circuit breaker sections of switchgear cabinets can loosen bolted connections, requiring periodic maintenance and re-torque to prevent increased resistance and thermal runaway, especially in compact setups where rear access is difficult.
Innovation Solution
A current transformer bushing and primary bus connector assembly allows for front-accessible mounting and re-torque of hardware, featuring a bayonet-style locking mechanism with internal ribs and locking fins, enabling secure connection of bus conductors without requiring hardware during initial assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the switchgear cabinet is designed with compact footprint to save space, then the cabinet size is reduced, but access to the rear portion for maintenance becomes difficult
Solution Approach 1:
The patent inverts the traditional maintenance access direction by enabling front-side access for torquing bus connections. The frame assembly includes a frame plate with a front opening that provides direct access to the bus connector and bolted connections from the front of the cabinet, eliminating the need for rear access while maintaining secure connections.
2Reliability
If high voltage connections are made to ensure proper electrical connectivity, then electrical performance is improved, but heat generation increases causing loosening of bolted connections
Solution Approach 1:
The patent applies preliminary action by providing a maintenance access path before thermal runaway or connection failure occurs. The frame plate with front opening allows operators to perform preventive torquing of bolted connections during scheduled maintenance, addressing heat-induced loosening before it causes failure.
3Reliability
If periodic maintenance is performed to prevent thermal runaway, then connection reliability is improved, but maintenance time and operational downtime increase
Solution Approach 1:
The patent inverts the traditional maintenance approach by enabling front-side access for all maintenance operations. The frame plate design allows operators to access and torque bus connections from the front of the cabinet, eliminating the need to open rear panels or access difficult-to-reach areas, thereby reducing maintenance time and operational downtime.
Data Source
AI summary
A front-accessible bus-connection mounting frame assembly in a draw out switchgear cabinet is fastened to the back wall of the breaker cabinet. The frame assembly provides for insertion and bayonet mounting of a primary bus connector's cylindrical conductor onto the mounting frame. The primary bus connector is bayonet mounted on the internal ribs of a central cylinder of the mounting frame assembly. The primary bus connector is then fixed in position by bolts front mounted down the central cylinder and out through a bus riser fitted at the back of the mounting frame assembly to establish electrical continuity. The central cylinder further provides a current transformer bushing tube around the primary bus connector and necessary flanges to mount the mounting frame assembly to the back wall and secure the current transformers around the bushing.