Thermistor Fitted in Stator Winding Gap for Accurate Temperature Detection
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Solution Overview
Problem
Conventional thermistor attachment methods in electric rotating machines suffer from low temperature detection accuracy and poor ability to follow sudden changes in stator winding temperature due to mechanical strength issues and improper placement, leading to variations in detected temperatures.
Innovation Solution
A thermistor is fitted into a minute gap among the connecting portions of segment conductors at the stator coil end, ensuring it is fully surrounded by the stator winding for improved accuracy and stability, eliminating the need for additional securing methods like lacing strings or adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the temperature measuring element portion of the thermistor is covered with a protecting member to ensure mechanical strength and oil resistance, then the mechanical strength and oil resistance are improved, but the temperature detection accuracy and ability to follow sudden temperature changes deteriorate due to insulation between the thermistor and stator winding
Solution Approach 1:
The patent uses a thin resin protective layer that provides mechanical strength and oil resistance while maintaining thermal conductivity. This thin film approach allows the thermistor to be protected without insulating it from the stator winding, thus preserving temperature detection accuracy.
Solution Approach 2:
The patent introduces a thermistor holder as an intermediary component that positions the thermistor in the gap between stator windings. The holder allows direct thermal contact between the thermistor and winding while providing structural support and protection.
2Strength
If the temperature measuring element portion of the thermistor is made with sufficient size to ensure mechanical strength, then the mechanical strength is improved, but the ability to fit into the gap between stator windings deteriorates
Solution Approach 1:
The patent divides the protective structure into separate components: a thin protective layer on the thermistor and a separate holder structure. This segmentation allows the thermistor element itself to remain small for fitting into the gap, while the holder provides the necessary mechanical strength and protection.
Solution Approach 2:
The patent employs a thin resin protective layer that provides adequate mechanical strength and oil resistance without adding significant size. This thin film approach maintains the compact dimensions needed for fitting into the limited gap space between stator windings.
3Stability of the object's composition
If the stator winding is made with large wire-diameter or rectangular wire to form segment conductors, then the rigidity of stator windings is improved, but the ability to form a gap adapted to receive the temperature measuring element portion deteriorates
Solution Approach 1:
The patent introduces a thermistor holder as an intermediary component that creates the necessary gap space. The holder is positioned between the thick rectangular wires and provides a dedicated cavity for the thermistor, allowing the stator windings to maintain their high rigidity while still accommodating the temperature measurement device.
Solution Approach 2:
The patent utilizes the radial dimension by positioning the thermistor in the gap between stator windings at the radial outer side of the stator core. This dimensional approach allows the use of thick rectangular wires for rigidity while creating space for the thermistor in the radial gap region.
4Ease of manufacture
If the temperature measuring element portion of the thermistor is installed to hug the stator winding on the front surface of the stator coil end, then the ease of installation is improved, but the temperature detection accuracy and ability to follow sudden temperature changes deteriorate due to insufficient surrounding by stator windings
Solution Approach 1:
The patent uses a thermistor holder as an intermediary that positions the thermistor deep within the stator winding structure. The holder places the temperature measuring element in the gap between windings, ensuring it is surrounded on multiple sides by stator windings that produce heat, thereby improving temperature detection accuracy while maintaining ease of installation through the holder 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 enhances temperature detection accuracy and the ability to track sudden changes in stator winding temperature, reducing variations and improving reliability and workability of the thermistor attachment.
Implementation Method 1
a thermistor for measuring the temperature of the stator winding
Data Source
AI summary
An electric rotating machine includes a rotor, a stator, and a thermistor. The thermistor has a temperature measuring element portion that is fitted in a minute gap defined by connecting portions of segment conductors at a stator coil end. The stator coil end is formed by arranging a plurality of the segment conductors in slots of a stator core to thereby form connecting portions of the segment conductors at the end portion of the stator core. The thermistor is separated from the connecting portions of the segment conductors only by dead air that defines the minute gap.