On-Load Slipring Grinding via Two-Directional Tool Movement
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Solution Overview
Problem
Current methods for slipring grinding in generators require shutdown and low-speed rotations, leading to prolonged downtime and maintenance challenges, especially in high-speed applications like turbo-alternators, where surface deformations cause brush sparking, wear, and erosion.
Innovation Solution
An on-load grinding method using a slip ring grinding machining tool with a grinding stone holder capable of two-directional movement, combining slow longitudinal and fast transversal pendulum movements, controlled by actuators, to adjust and smooth the slipring surface while the generator is operational.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If slipring grinding is performed using conventional methods, then the slipring surface can be ground, but the generator must be shut down and operated at low speed, causing prolonged downtime
Solution Approach 1:
The invention makes the grinding system dynamic by enabling it to operate while the generator runs at normal speed. The grinding tool is mounted on the rotor and rotates with it, allowing the grinding stone to contact the slipring surface while both rotate together at operational speeds, eliminating the need for shutdown and low-speed operation
Solution Approach 2:
The invention merges the grinding operation with the normal generator operation. By mounting the grinding tool on the rotor assembly and using the rotational motion already present during generator operation, the grinding process is combined with the operational state, allowing maintenance to be performed without stopping the generator
2Manufacturing precision
If the grinding stone holder is displaced only in one direction, then the structure is simpler, but the grinding coverage and surface uniformity are insufficient
Solution Approach 1:
The invention adds a second dimension of movement to the grinding stone holder by implementing both longitudinal displacement (along the axis of rotation) and radial displacement (toward and away from the slipring surface). This two-directional movement capability allows the grinding stone to cover the entire slipring surface uniformly, improving grinding quality while maintaining reasonable structural complexity
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
This method significantly reduces downtime, extends brush life, and maintains optimal electrical contact by smoothing the slipring surface, reducing deformations to less than 50 μm, thereby enhancing operational reliability and extending maintenance intervals.
Implementation Method 1
an on-load grinding method using a slip ring grinding machining tool with a grinding stone holder
Data Source
AI summary
This invention relates to methods and materials for slip ring grinding of a generator rotor, without the need of dismounting the slip ring from the rotor of the generator, and allowing the grinding process to be performed whilst the generator is on full-load operation. As such the methods and materials of the present invention differs from current solution. Whilst allowing on-line grinding of the slip ring, the current solutions require low-speed rotations and accordingly operational shutdown of the generator. Allowing on-load grinding, the present invention greatly shortens the downtime of the generator and to perform maintenance on the slip ring beyond the provided standard maintenance schedule.