Electric Motor Winding Head Temperature Sensor Placement
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Solution Overview
Problem
In electric motors with distributed windings, particularly wave windings, temperature sensors face challenges in accurate temperature measurement due to the rigid design, leading to lower measured temperatures and time lags, as they are not easily insertable between coil layers, resulting in undesirable error influences and reduced performance.
Innovation Solution
A method is introduced where a placeholder is inserted between coil layers to create a gap-shaped recess, allowing the coil layers to be pressed and deformed to form a receiving chamber for the temperature sensor, enabling full-surface contact and accurate temperature measurement at the hottest location inside the winding head, rather than just on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a temperature sensor is inserted radially or axially on the winding head surface, then the sensor can be easily installed, but the temperature measurement accuracy deteriorates because the sensor only contacts the surface at certain points and does not reach the hottest interior location
Solution Approach 1:
A placeholder is inserted between the coil layers before the winding head is impregnated with insulating material. This preliminary placement ensures that the temperature sensor will later be positioned at the optimal location (inside the winding head) for accurate temperature measurement, rather than being installed after impregnation when access would be difficult
Solution Approach 2:
The placeholder acts as an intermediary object that occupies the space between coil layers during manufacturing. It enables the temperature sensor to be positioned correctly by serving as a temporary guide and space-holder, allowing the sensor to reach the interior hottest location without requiring complex post-impregnation installation procedures
2Strength
If the winding head is impregnated with insulating material first, then the structural integrity is improved, but the temperature sensor becomes difficult to insert into the interior location
Solution Approach 1:
The placeholder is inserted between the coil layers before the impregnation process. This preliminary action secures the sensor's future position and ensures that when the winding head is impregnated, the placeholder (and subsequently the temperature sensor) remains accessible and can be properly positioned inside the hardened insulating material
Solution Approach 2:
The placeholder serves as a mediator that bridges the conflicting requirements of structural integrity and sensor insertability. By being present during impregnation, it ensures the insulating material cures around the correct location, and after impregnation, it can be removed to leave a cavity for the temperature sensor, thus maintaining both structural integrity and sensor access
3Area of stationary object
If round coils are used with larger distance between adjacent coils, then the temperature sensor has more installation space, but the power density and compactness of the motor deteriorates
Solution Approach 1:
Instead of creating installation space by increasing radial distance between coils (which would reduce power density), the invention creates space in the axial dimension by inserting the placeholder between coil layers. This allows the temperature sensor to be positioned inside the winding head without requiring larger gaps between adjacent coils, thus maintaining high power density while providing adequate installation space
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 method significantly improves temperature measurement accuracy in wave winding electric motors, reducing error influences and allowing for maximum performance operation by ensuring the temperature sensor measures at the interior hottest location, rather than just the surface.
Implementation Method 1
the first coil layer is then pressed onto a circumferential surface of the placeholder and onto the second coil layer, i.e., in the direction of the second coil layer, and is plastically deformed in such a way that a space, previously present between the lateral surfaces of the two coil layers and the circumferential surface of the placeholder, is reduced, and a contact surface between the lateral surface of the first coil layer and the circumferential surface of the placeholder is enlarged
Data Source
AI summary
In a method for manufacturing an electric motor comprising a rotor and a stator a placeholder for a temperature sensor is inserted in the axial direction between a first coil layer and an adjacent second coil layer of a winding head such that the placeholder is situated in a gap-shaped recess extending between the first and the second coil layers, the first coil layer is then pressed onto a circumferential surface of the placeholder and onto the second coil layer and is plastically deformed such that a space between the lateral surfaces of the two coil layers and the circumferential surface of the placeholder is reduced, and a contact surface between the lateral surface of the first coil layer and the circumferential surface of the placeholder is enlarged. By removing the placeholder, a receiving chamber is subsequently formed in the winding head, into which a temperature sensor is then inserted.