Generator Grounding Strap Module With Redundant Shaft Contact
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Solution Overview
Problem
Large rotating shafts in generators face electrical charge buildup, which can lead to damage through discharge through the oil film in bearings, necessitating continuous grounding to prevent such damage.
Innovation Solution
A modular generator grounding strap system with redundant straps and sensors is introduced, where the grounding strap assembly includes a braided metal grounding strap with a redundant strap configuration and sensors to monitor strap integrity and maintain continuous grounding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single grounding strap is used, then the device complexity is reduced, but the reliability decreases due to lack of redundancy
Solution Approach 1:
The grounding system is divided into multiple independent grounding straps (first grounding strap and second grounding strap) that can be separately installed and function independently. This segmentation provides redundancy while keeping each individual strap simple in structure.
Solution Approach 2:
The system incorporates a backup grounding strap that is positioned and ready to provide grounding continuity in advance, before any failure occurs. The biasing assembly ensures the backup strap is pre-loaded and will immediately engage if the primary strap fails.
2Reliability
If sensors are added to monitor strap integrity, then the reliability is improved through early failure detection, but the device complexity increases
Solution Approach 1:
Sensors are integrated into the grounding strap system to continuously monitor the integrity and position of the grounding straps. The sensors provide feedback signals to indicate whether the straps are properly engaged with the rotor shaft, enabling real-time monitoring of grounding status.
Solution Approach 2:
The grounding strap system incorporates self-monitoring capabilities through integrated sensors that automatically detect strap displacement or failure without requiring external inspection systems. The system self-diagnoses its grounding status and can trigger alarms or shutdowns based on sensor readings.
3Reliability
If redundant straps are implemented, then the reliability is improved through fail-safe operation, but the ease of operation decreases due to more complex installation
Solution Approach 1:
The grounding straps are designed with dynamic positioning capabilities, allowing them to move and adapt to rotor shaft position variations during operation. The biasing assemblies provide automatic adjustment mechanisms that maintain optimal contact pressure without requiring precise manual positioning during installation.
Solution Approach 2:
The grounding straps utilize flexible conductive materials that can conform to the rotor shaft surface and accommodate minor misalignments. This flexibility simplifies installation by reducing the precision requirements for strap positioning while maintaining reliable electrical contact.
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
The modular grounding strap system effectively prevents electrical discharge by ensuring continuous contact with the rotating shaft, with redundant straps providing fail-safe operation and sensors monitoring for strap failure, thus protecting the generator bearings.
Implementation Method 1
a biasing assembly that applies a biasing force to the mounting block to maintain contact between the grounding strap assembly and the rotor shaft
Implementation Method 2
shaft grounding devices (SGD) are placed in continuous contact with the rotating shaft as it rotates to provide a discharge path to ground
Data Source
Figure 1~2
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AI summary
A generator grounding module selectively mountable to a support bracket and selectively engageable with a rotor includes a plate member movable along a mounting axis to selectively attach the generator grounding module to the support bracket, the plate member movable between a first position and a second position in which the plate member is substantially fixed with respect to the support bracket. A mounting block is movable along the mounting axis with respect to the plate member, a grounding strap is coupled to the mounting block and is movable between a disengaged position and an engaged position in which the grounding strap contacts the rotor, and a biasing assembly is connected to the plate member and the mounting block and operable to bias the mounting block along the mounting axis toward the plate member, wherein the plate member is fixedly attached to the support bracket when in the second position and the biasing assembly biases the grounding strap into the engaged position.