Neutral Point Bus Bar Layout for Accurate Motor Coil Temperature Sensing
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Solution Overview
Problem
Existing rotating electrical machines face challenges in accurately measuring temperature due to current flow between neutral terminals of different phase windings, leading to inaccurate temperature detection and potential damage.
Innovation Solution
A rotating electrical machine design featuring a neutral point bus bar in an arc shape with a thermistor positioned to face the connection point of the V-phase coil, integrated through molding, allowing temperature measurement regardless of current flow between coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is provided on a connection member that connects neutral terminals of different phase windings, then temperature detection is enabled, but accurate temperature measurement cannot be achieved when current flows between neutral terminals
Solution Approach 1:
The temperature sensor is extracted from the connection member and relocated to the neutral point bus bar at a position not affected by current flow between neutral terminals. This separates the temperature detection function from the current conduction path, allowing accurate temperature measurement independent of current flow conditions.
Solution Approach 2:
The neutral point bus bar serves as an intermediary structure that provides both current conduction and temperature detection functions. By positioning the temperature sensor on the bus bar rather than on connection members, the system uses the bus bar as a stable reference point for temperature measurement that is not influenced by dynamic current flow between phases.
2Reliability
If connection members are used to connect neutral terminals, then electrical connection is achieved, but temperature measurement accuracy deteriorates due to current flow through connection members
Solution Approach 1:
The electrical connection system is segmented into distinct functional components: connection members for current conduction and the neutral point bus bar for temperature reference. This segmentation allows the temperature sensor to be positioned on the bus bar where it is not exposed to current flow, while connection members maintain their current conduction function.
Solution Approach 2:
The temperature detection function is extracted from the connection members and relocated to the neutral point bus bar. This extraction eliminates the interference between current flow in connection members and temperature measurement, as the sensor now resides on a component that provides a stable thermal reference point.
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
Accurate temperature measurement is ensured, preventing damage and enabling effective control, with improved assembly efficiency and reduced cost by direct integration without adhesives.
Implementation Method 1
a temperature detector configured to detect a temperature of the three-phase coil
Implementation Method 2
a neutral point bus bar forming a neutral point of the three-phase coil and formed of a conductive plate
Data Source
AI summary
A rotating electrical machine includes: a three-phase coil including a U-phase coil, a V-phase coil, and a W-phase coil each formed of a flat wire; a neutral point bus bar forming a neutral point of the three-phase coil and formed of a conductive plate; and a temperature detector configured to detect a temperature of the three-phase coil. The neutral point bus bar is formed in an arc shape along an outer periphery of the three-phase coil. One end of one coil in the three-phase coil is connected to a vicinity of a center of the neutral point bus bar in a circumferential direction thereof. One end of each of remaining two coils in the three-phase coil is connected to a vicinity of an end of the neutral point bus bar in the circumferential direction.