Stator Winding Temperature Sensor with Protective Tab
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Solution Overview
Problem
Resistance-based temperature sensors (RTDs) used in motor and generator stator windings are prone to damage during installation and manufacturing due to stress and pressure, leading to tensile failures, as the thin fiberglass body and large leads do not fit inside the stator core, requiring a 'lead step' that makes them susceptible to damage.
Innovation Solution
A stator winding temperature sensor with a fiberglass body and epoxy laminate material, featuring a thicker 0.040 inch body and an elongated tab to protect the sensing wire coil in the pinch and strike zones, and a visible joint location to facilitate precise installation, reducing the likelihood of damage and failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a thin fiberglass body with large leads is used for the RTD, then the RTD can be installed between coils inside the stator, but the RTD becomes susceptible to damage during motor or generator manufacturing due to stress and pressure
Solution Approach 1:
The patent changes the physical parameters of the RTD by increasing the fiberglass body thickness from thin to 0.040 inch, and modifies the lead configuration by adding an elongated tab. These parameter changes enable the RTD to withstand manufacturing stresses while maintaining installation capability between stator coils.
Solution Approach 2:
The patent uses a composite structure combining fiberglass body material with an elongated tab that encompasses the lead step. This composite design provides both mechanical protection and electrical functionality, allowing the RTD to resist damage during manufacturing while maintaining its sensing capability.
2Strength
If the fiberglass body thickness is increased to protect the sensing wire coil, then the RTD becomes more robust against damage, but the RTD may not fit inside the stator core
Solution Approach 1:
The patent applies local quality by providing enhanced protection (0.040 inch fiberglass body) specifically at critical locations where the sensing wire coil is most vulnerable, while maintaining a compact overall form factor that fits within the stator core. The elongated tab provides localized protection at the lead step without increasing the main body volume.
3Ease of manufacture
If a lead step configuration is used to connect sensing wire coil to lead wire, then electrical connection is achieved, but the lead step becomes a vulnerable point susceptible to damage
Solution Approach 1:
The patent implements beforehand cushioning by designing an elongated tab that encompasses and protects the lead step before damage can occur during manufacturing. This protective structure is built into the RTD design, providing pre-cushioning against the stresses and pressures encountered during motor or generator assembly.
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
The solution increases the strength of the internal sensing wires to withstand pressures up to 120 PSI, with external fiberglass damage visible before internal wire damage occurs, preventing over-stressing and improving manufacturing processes.
Implementation Method 1
A resistance-based temperature sensor, or resistance temperature detection element (RTD), can be used in a number of applications to measure operating temperature based on a sensed change in resistance in one or more wires incorporated into the sensor.
Data Source
AI summary
Disclosed herein, among other things, is a stator winding temperature sensor. According to an embodiment, the sensor includes at least one sensing wire coil adapted to be connected to a stator. The sensor also includes a body, including a core material surrounding at least a portion of the sensing wire coil, and a laminate material over the core material. The body has a thickness adapted to protect the sensing wire coil. The sensor includes a lead wire adapted to connect to an external monitoring device. The sensing wire coil is electrically connected to the lead wire at a lead step portion of the sensor. In addition, the sensor includes a tab extending from the lead wire and encompassing the lead step. The tab protects the lead step and the sensing wire coil in a region where the sensor extends over an end of the stator.