Fan-Shaped Segment Core Slots for Rotor Slot Clearance
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Solution Overview
Problem
High-speed rotation in rotating electrical machines with fan-shaped segment cores causes circumferential ends to displace radially outwardly, leading to narrow areas in rotor slots and potential damage to rotor windings due to protrusion of slot edges.
Innovation Solution
Designing slots in fan-shaped segment cores to be larger near circumferential ends and progressively smaller toward intermediate portions, or larger than intermediate slots near fastening bolts, to prevent peripheral edges from protruding into adjacent slots during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fan-shaped segment cores are used in rotor core, then the rotor core can be constructed by stacking annular steel plates, but high-speed rotation causes circumferential ends to displace radially outwardly creating narrow areas in slots
Solution Approach 1:
The slot width is made non-uniform along the circumferential direction, with wider slots at the circumferential ends and narrower slots at intermediate portions. This local variation in slot dimensions compensates for the radial displacement that occurs at circumferential ends during high-speed rotation, preventing the formation of narrow areas that would compromise winding insulation.
Solution Approach 2:
The slot width parameter is deliberately varied in the circumferential direction to account for displacement effects. By making slots wider at positions prone to radial displacement and narrower at stable positions, the design maintains adequate clearance between windings and slot edges under all operating conditions.
2Speed
If circumferential ends of segment cores are displaced radially outwardly during high-speed rotation, then the displacement occurs, but slots near circumferential ends shift radially outwardly and circumferentially inwardly producing narrow areas
Solution Approach 1:
The slot dimensions are pre-adjusted during manufacturing to counteract the expected displacement that will occur during operation. By making slots wider at circumferential ends before assembly, the design anticipates and compensates for the radial and circumferential shifts that will happen at high rotation speeds, preventing narrow area formation.
Solution Approach 2:
Different slot widths are applied at different circumferential positions based on their displacement characteristics. Slots near circumferential ends are made wider to accommodate expected displacement, while slots at intermediate portions maintain standard dimensions, creating a non-uniform slot width distribution along the circumferential direction.
Data Source
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AI summary
The present invention provides a rotating electrical machine including a rotor core that does not produce narrow areas in rotor slots even if circumferential ends of fan-shaped segment cores are displaced radially outwardly and circumferentially during operation. In the present invention, slots (16) near circumferential ends of the fan-shaped segment cores (9, 10) are made larger than slots (11) in circumferential intermediate portions of the segment cores (9, 10). With such a configuration, even if the circumferential ends of the segment cores (9, 10) are displaced radially outwardly and circumferentially during operation, the circumferential ends of the segment cores (9, 10) forming the large slots (16) do not protrude into the slots (11) formed in the circumferential intermediate portions of axially adjacent segment cores (9, 10), thereby preventing narrow areas from being produced in the rotor slots.