Rotating Resistor Assembly Mitigates Centrifugal Forces
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Solution Overview
Problem
Generators face challenges in protecting the rotating rectifier assembly and suppression resistors from centrifugal forces, which can lead to instability and reduced maximum obtainable speed of the rotor shaft.
Innovation Solution
A resistor pack assembly is designed with a cylindrical suppression resistor and mounting plates sandwiched between a cover, providing structural support and electrical isolation, while a cylindrical grounding resistor offers a path to ground, preventing charge buildup and enhancing shaft stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If suppression resistors are mounted on the rotating shaft within the rotating rectifier assembly, then voltage and current transients are suppressed and the rotating rectifier assembly is protected, but the rotor shaft speed is limited due to centrifugal forces affecting the mounted components
Solution Approach 1:
The suppression resistors are extracted from the rotating rectifier assembly and mounted separately on the rotor shaft. This separation allows the resistors to be positioned in a location that is less susceptible to centrifugal forces, enabling higher rotor speeds while maintaining protection functionality
Solution Approach 2:
A dedicated mounting structure with mounting plates and fastening mechanisms is introduced as an intermediary between the suppression resistors and the rotor shaft. This intermediary structure provides mechanical support and electrical isolation, allowing the resistors to function effectively without being directly subjected to the harsh rotational environment
2Reliability
If suppression resistors are mounted on the rotating shaft, then an alternate path for voltage and current transients is provided, but structural stability and shaft stiffness are reduced due to the mounted components
Solution Approach 1:
Electrical insulation materials and thin film coatings are used between the suppression resistors and the rotor shaft to provide electrical isolation while maintaining mechanical stability. This allows the resistors to be mounted without compromising the structural integrity and stiffness of the shaft
Solution Approach 2:
The mounting structure is segmented into separate components including mounting plates, fastening mechanisms, and positioning features. This segmentation allows for optimized placement that minimizes interference with the shaft's structural properties while maintaining the protection function
Data Source
AI summary
A resistor pack assembly includes a first mounting plate, a second mounting plate, a cylindrical suppression resistor, and a cylindrical cover. The first mounting plate has a circular face, a first connection terminal, and a second connection terminal. The second mounting plate has a circular face, a third connection terminal and a fourth connection terminal. The cylindrical suppression resistor has a first flat surface and a second flat surface opposite the first flat surface, and is located between the first mounting plate and the second mounting plate, wherein the first flat surface contacts the circular face of the first mounting plate and the second flat surface contacts the circular face of the second mounting plate. The cylindrical cover has an inner diameter aperture, wherein the first mounting plate, the second mounting plate, and the cylindrical suppression resistor are located within the inner diameter aperture of the cylindrical cover.