scholarly journals High Temperature Resistant Eddy Current Sensor for “in situ” Monitoring the Material Microstructure Development of Steel Alloys during Heat Treatment – Bainite Sensor

2011 ◽  
Vol 25 ◽  
pp. 1605-1608 ◽  
Author(s):  
H. Klümper-Westkamp ◽  
H.-W. Zoch ◽  
W. Reimche ◽  
F.W. Bach
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Eddy Current ◽  
In Situ Monitoring ◽  
Current Sensor ◽  
Microstructure Development ◽  
Material Microstructure ◽  
Steel Alloys ◽  
Eddy Current Sensor

Eddy current sensor for in-situ monitoring of swelling of Li-ion prismatic cells

2015 ◽  
Author(s):  
Yuri Plotnikov ◽  
Jason Karp ◽  
Aaron Knobloch ◽  
Chris Kapusta ◽  
David Lin
Keyword(s):  
Eddy Current ◽  
In Situ Monitoring ◽  
Current Sensor ◽  
Eddy Current Sensor ◽  
Li Ion

scholarly journals Temperature Drift Compensation of Eddy Current Sensor under High Temperature Environment

2018 ◽  
Vol 38 ◽  
pp. 04005
Author(s):  
Ping He ◽  
YunKai Ma ◽  
Hui Chen
Keyword(s):  
High Temperature ◽  
Eddy Current ◽  
Measurement Accuracy ◽  
Compensation Method ◽  
Current Sensor ◽  
High Precision Measurement ◽  
Temperature Drift ◽  
Eddy Current Sensor ◽  
Practical Engineering ◽  
Drift Compensation

Eddy current sensor is an sensor based on eddy current effect. In practical engineering applications, the ambient temperature of eddy current sensor may be up to 135 ℃. The temperature drift of eddy current sensor magnifies the error of displacement detection. In this paper, the main factors that cause temperature drift are analyzed in detail, and the results show that the compensation based on single parameter can not meet the demand of high-precision measurement. For this reason, this paper proposes an external compensation method which applies mathematical fitting to realize compensation for temperature drift. The experimental results show that the measurement accuracy of the external compensation method reaches 0.25% in the working temperature range, which greatly improves the measurement accuracy of eddy current sensor under high temperature.

Tip-Clearance Measurements on an Engine High Pressure Turbine Using an Eddy Current Sensor

2017 ◽  
Author(s):  
V. Sridhar ◽  
K. S. Chana
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Turbine ◽  
Eddy Current ◽  
Health Monitoring ◽  
Tip Clearance ◽  
Current Sensor ◽  
High Pressure Turbine ◽  
Eddy Current Sensor ◽  
Health Monitoring Systems

Gas turbine health monitoring is an important area of research. As the performance of aircraft and power plants increase, they will require better sensors for health monitoring systems to prevent failures. Health monitoring systems help in preventive maintenance reducing unnecessary downtime and maintenance costs. Gas turbine blades are subjected to dynamic loads caused by rotor imbalances, distortions in the intake flows etc. These loads cause low or high cycle fatigues and the blades can fail over time. Tip-timing and tip-clearance systems makes it possible to assess turbomachinery blade vibration by using non-contact measurement systems such as optical, eddy current, hall effect, capacitve etc. The most widely used systems in industry are optical, however, these systems are still largely prone to contamination problems from dust, dirt, oil, water etc. Further development of these systems for in-service use is problematic because of the difficulty in eliminating contamination of the optics. Other systems, although immune to contamination, may not be able to measure both tip-clearance and tip-timing at the same time due to their operating principle. Another limitation is that they cannot be used in high temperature applications such as in a high pressure turbine where the temperatures can reach 1400°C. Eddy current sensors are found to be quite robust and can measure both tip-timing and tip-clearance. They are currently being used for gas turbine health monitoring applications at low temperatures such as in the compressor stage and last stage of a steam turbine. A new high temperature eddy current sensor has been developed in-house at the University of Oxford for application in gas turbine tip-timing and tip clearance measurements to assess blade vibrations. The current sensor is a modified version of the existing eddy current sensor that is able to operate at high temperatures of about 1400°C. The paper presents the development of the sensor and experimental results of tip clearance measurements in the high pressure turbine stage of a jet engine. In the engine tests, two blades were reduced in height to increase the tip-clearance and the measurements were taken at both idle and max operating speeds. The sensor was found to work in these harsh environments and was sufficiently sensitive to accurately determine the tip clearance at these elevated temperatures. Tests were carried out mainly to demonstrate the technique of obtaining good tip clearance measurements and the survivability of the sensors in the high temperature and pressure environment.

Inspection of Surface Rolled Sintered Gears using Eddy-Current Sensor

2013 ◽  
Vol 133 (5) ◽  
pp. 300-306
Author(s):  
Tsutomu Mizuno ◽  
Yuichi Asato ◽  
Sho Goto ◽  
Takashi Watanabe ◽  
Teruie Takemasu ◽  
...  
Keyword(s):  
Eddy Current ◽  
Current Sensor ◽  
Eddy Current Sensor

scholarly journals Eddy Current Sensor System for Tilting Independent In-Process Measurement of Magnetic Anisotropy

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2652
Author(s):  
Frank Wendler ◽  
Rohan Munjal ◽  
Muhammad Waqas ◽  
Robert Laue ◽  
Sebastian Härtel ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Eddy Current ◽  
Digital Signal ◽  
Production Equipment ◽  
Sensor System ◽  
Current Sensor ◽  
Cold Forming ◽  
Eddy Current Sensor ◽  
Two Samples ◽  
Internal Mechanical Stress

Modern production equipment is based on the results of quality control as well as process parameters. The magnetic anisotropy of materials is closely connected to internal mechanical stress by the Villari effect, and also to hardening effects due to plastic deformations, and could therefore provide an interesting basis for process control. Nevertheless, the analysis of anisotropic properties is extremely sensitive to sensor and workpiece misalignments, such as tilting. In this work, a novel eddy current sensor system is introduced, performing a non-contact measurement of the magnetic anisotropy of a workpiece and realizing a separation and correction of tilting effects. The measurement principle is demonstrated with the example of two samples with different magnetic anisotropy values induced by cold forming. Both samples are analyzed under different tilt angles between the sensor axis and the surface of the workpiece. In this work, digital signal processing is demonstrated on the acquired raw data in order to differentiate the effects of tilt and of anisotropy, with the use of preliminary results as an example of two prepared samples.

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