Fiber Optic Temperature Sensor for High-Field Environments
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Solution Overview
Problem
Temperature sensors for electric machines in electromagnetic environments face challenges such as false alarms, high costs, and mechanical vibrations, with existing fiber optic sensors experiencing noise and reproducibility issues due to non-negligible light travel and movement, requiring complex analysis equipment and precise mechanical adjustments.
Innovation Solution
A fiber optic temperature sensor system using a non-conductive temperature-sensitive element with a two-face mirror target that reflects light at 45-degree angles, allowing for calibration against ambient changes and minimizing metallic components, enabling simpler light analysis and robustness against vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a variable air gap principle is used with metallic reflective surfaces and optical fibers, then temperature sensing capability is achieved, but light noise increases and measurement reproducibility deteriorates
Solution Approach 1:
The patent introduces a non-conductive rod as an intermediary element between the optical fibers and the temperature sensing mechanism. This rod serves as a mediator that transmits temperature changes through thermal expansion while preventing direct optical interference between the fibers, thus reducing light noise while maintaining temperature measurement capability
Solution Approach 2:
The patent replaces the metallic reflective surface mechanism with a non-conductive rod that uses thermal expansion to modulate light transmission. This substitution eliminates the harmful optical reflections and interference patterns caused by metallic surfaces while maintaining the temperature-to-light conversion function
2Strength
If metallic or conductive components are used in the temperature sensing head, then structural strength is improved, but electromagnetic interference increases and partial discharge occurs
Solution Approach 1:
The patent employs composite material construction for the sensor housing and structural components, combining non-conductive materials with appropriate mechanical properties. This allows the sensor to maintain structural strength and rigidity while being electrically isolated from electromagnetic fields, preventing interference and partial discharge in high-voltage environments
3Measurement precision
If complex interference pattern analysis equipment is used, then temperature measurement capability is enhanced, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for complex interference pattern analysis equipment by using a non-conductive rod mechanism that produces simple, direct light transmission changes in response to temperature. This reduces the measurement system to basic light detection without requiring sophisticated optical analysis instruments
4Reliability
If precise mechanical adjustment is implemented for minimum lateral friction, then measurement stability is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent employs a non-conductive rod that is freely movable within its housing, allowing it to expand and contract with temperature changes without requiring precise mechanical adjustments or lubrication systems. The design inherently minimizes friction through proper clearance design, achieving measurement stability without complex manufacturing requirements
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 system provides accurate, cost-effective temperature measurement in electromagnetic environments with reduced noise and complexity, utilizing a non-conductive design and simpler light analysis, while minimizing mechanical interference and maintaining precision across a range of temperatures.
Implementation Method 1
a non-conductive temperature-sensitive element (50) disposed so as to interfere with at least a portion of the light received by the receiver when the element undergoes a dimensional change in response to a temperature change
Implementation Method 2
A fiber optic temperature sensor system using a non-conductive temperature-sensitive element with a two-face mirror target that reflects light at 45-degree angles
Data Source
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AI summary
A temperature sensor, capable of operating in electromagnetic and/or electric environments such as electrical generators, motors and transformers and/or in environments where vibratory conditions are frequent or continuous, contains at least one light emitting optic fiber and one light receiving optic fiber and an electrically non- conductive dilatable object which variably occults the emitted light as the object's temperature varies. The light receiving optic fiber transmits light intensity and light intensity changes to an electronic device that may include a photometer and light-to- temperature computing equipment.