Salient-Pole Rotor Insulation for Creepage Distance
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Solution Overview
Problem
The existing cooling structures for salient-pole rotors, which include a ventilation path penetrating the field winding in the radial direction, fail to adequately secure a long creepage insulation distance between the high potential field winding and the grounding parts, such as the rotation shaft and magnetic head.
Innovation Solution
The implementation of a ventilation groove on the inner peripheral surface of the field winding, a ventilation hole in the magnetic head, and a stepped portion at the magnetic head side of the ventilation groove, along with an insulating member and insulation block, forms a ventilation path that allows for effective cooling of the field winding while maintaining a long creepage insulation distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ventilation path penetrating the field winding in the radial direction is provided, then the cooling effect of the field winding is improved, but the creepage insulation distance between the field winding and grounding parts is shortened
Solution Approach 1:
The ventilation path is divided into two separate components: a ventilation groove formed in the field winding and a ventilation hole formed in the magnetic head. This segmentation allows the cooling function to be maintained while the insulation distance is preserved, as the groove and hole are positioned such that they do not compromise the creepage path between high potential and ground potential members.
Solution Approach 2:
An insulating member is introduced as an intermediary component between the field winding and the magnetic head. This insulating member bridges the ventilation groove and ventilation hole, enabling thermal cooling while maintaining electrical insulation. The insulating member acts as a mediator that allows the ventilation path to function without compromising the creepage insulation distance.
2Device complexity
If the cooling airflow is applied only to the outer surface of the field winding, then the insulation structure is simple, but the internal cooling of the field winding is inadequate
Solution Approach 1:
The cooling system is segmented into external cooling (airflow over outer surface) and internal cooling (airflow through ventilation groove and hole). This segmentation enables both simple external cooling structure and effective internal cooling, as the ventilation groove and hole provide a dedicated path for cooling airflow to reach the internal regions of the field winding without complicating the overall structure.
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 configuration ensures efficient cooling of the field winding from the inner side and secures a longer creepage insulation distance, enhancing the reliability of the insulation and preventing thermal degradation.
Implementation Method 1
blowing the cooling airflow into this ventilation path, have been provided
Implementation Method 2
a stepped portion formed at a portion, at the magnetic head side, of the ventilation groove... securing a long creepage insulation distance
Data Source
AI summary
To cool field winding from its inner peripheral side and increase an insulation performance, salient-pole rotor (3) has rotor yoke (12) provided along rotation shaft (11), magnetic cores (13) protruding outward in radial direction from outer peripheral portion of rotor yoke (12) and arranged at regular intervals in circumferential direction, magnetic head (14) provided at radial direction outer side of magnetic core (13), and field winding (15) wound around outer peripheral surface of magnetic core (13) between rotor yoke (12) and magnetic head (14). And, insulating structure of ventilation path of salient-pole rotor (3) has ventilation groove (15a) opening to inner peripheral surface of field winding (15) and penetrating field winding (15) in radial direction, ventilation hole (14a) penetrating magnetic head (14) in radial direction and communicating with ventilation groove (15a), and stepped portion (15b) formed at portion, at magnetic head (14) side, of ventilation groove (15a).