Electric Machine Cooling via Segmented Housing Openings
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Solution Overview
Problem
Existing electrical machines suffer from inefficient cooling, with most of the circulated cooling medium being recirculated in a short-circuit flow rather than being effectively exchanged past the temperature-critical end windings and short-circuit ring, leading to inadequate heat dissipation.
Innovation Solution
The electrical machine design incorporates circumferentially arranged first and second openings in the housing, with a fan having radially extending blades to rapidly draw in and expel the cooling medium, minimizing short-circuit flows and optimizing the flow path to ensure maximum exchange and throughput past the stator windings and short-circuit ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If rotor blades are designed to circulate cooling medium, then cooling medium circulation is achieved, but short-circuit flow occurs and fresh cooling medium exchange is reduced
Solution Approach 1:
The housing is segmented with separate first openings for suction and second openings for blowout, creating distinct flow paths that prevent mixing of incoming and outgoing cooling medium, thereby eliminating short-circuit flow while maintaining circulation
Solution Approach 2:
The fan acts as an intermediary device that actively directs cooling medium from the first openings through the electrical machine components to the second openings, ensuring unidirectional flow and maximizing fresh cooling medium exchange
2Loss of energy
If cooling medium is circulated through the electrical machine, then heat dissipation is achieved, but most cooling medium is recirculated instead of being exchanged
Solution Approach 1:
The cooling medium flow is transitioned from a two-dimensional recirculation pattern to a three-dimensional flow path that enters through circumferential first openings, passes through the components, and exits through second openings, maximizing exposure to heat-generating areas while ensuring fresh medium exchange
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 design enhances cooling efficiency by maximizing the flow of fresh cooling medium to critical areas, reducing short-circuit currents and improving heat dissipation, thereby improving the performance and reliability of the electrical machine.
Implementation Method 1
Due to the rotation of the fan blades with the rotor during operation of the electrical machine, the cooling medium is conveyed outwards in the radial direction
Implementation Method 2
The cooling medium conveyed radially flows in the direction of the end windings. Only a small part of the cooling medium conveyed by the fan is conveyed out of the housing of the electrical machine past the end windings and/or the short-circuit ring
Data Source
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AI summary
The invention relates to an electric machine (2) comprising a rotor (10), a stator (20) with a circumferentially arranged stator winding (22) that consists of an electrically conductive material, and a housing (30) with a first and a second opening (32, 34) extending in a circumferential direction. A ventilator (40) is arranged on the end-face side of the rotor (10), said ventilator being connected to the rotor (10) in a rotationally fixed manner and having radially extending vanes (42). A cooling medium (46) is aspirated from the ventilator (40) via the first opening (32), blown out via the second opening (34) and swiftly conveyed past, at least at sub-regions of the stator winding (22), between said first and second opening (32,34).