Rotor Crossover Wire Layout for Compact Wound Field Machines
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Solution Overview
Problem
In wound field rotating electrical machines, the crossover wires wound around the rotor core can come into contact, necessitating an increase in coil film thickness for insulation, which reduces the space factor of the conductor in the slot.
Innovation Solution
The design includes one side crossover wires and other side crossover wires disposed on both sides of the rotor core's axial direction, connecting non-adjacent teeth, thereby avoiding contact and allowing for thinner coil films without compromising insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the coil film is increased to ensure insulation between crossover wires, then insulation reliability is improved, but the space factor of the conductor in the slot is reduced
Solution Approach 1:
The patent introduces a radial dimension for insulation by positioning insulation ribs on the inner diameter surface of the rotor core. Instead of increasing coil film thickness in the axial direction, the insulation is provided in the radial direction between adjacent crossover wires, thereby resolving the contradiction between insulation reliability and conductor space factor.
2Adaptability or versatility
If multiple crossover wires are positioned on the one side end surface of the rotor core, then connectivity between non-adjacent teeth is improved, but the risk of contact between crossover wires increases
Solution Approach 1:
The patent introduces insulation ribs as intermediary structures positioned between adjacent crossover wires on the inner diameter surface of the rotor core. These ribs act as mediators that prevent direct contact between crossover wires while maintaining their connectivity function, thereby resolving the contradiction between adaptability and insulation reliability.
3Reliability
If the coil film thickness is increased, then insulation between crossover wires is ensured, but the compactness of the motor design is reduced
Solution Approach 1:
The patent moves the insulation function from the axial dimension (coil film thickness) to the radial dimension (insulation ribs on rotor core inner diameter). This dimensional shift allows for thinner coil films and smaller motor volume while maintaining insulation reliability through the radially positioned insulation ribs.
Data Source
AI summary
A wound field rotating electrical machine includes: a stator; and a rotor facing the stator in a radial direction. The rotor includes a rotor core including multiple teeth and multiple slots in a circumferential direction, and a coil as a field winding wound around each tooth. The coil includes a one side crossover wire disposed along a one side end surface of the rotor core in an axial direction and connecting two first winding portions wound respectively in a concentrated manner around two of the teeth which are not adjacent to each other, and an other side crossover wire disposed along an other side end surface of the rotor core in the axial direction and connecting two second winding portions that are different from the first winding portions and that are wound respectively in a concentrated manner around two of the teeth which are not adjacent to each other.