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A wide linear range Eddy Current Displacement Sensor equipped with dual-coil probe applied in the Magnetic Suspension Flywheel.

Fang J, Wen T - Sensors (Basel) (2012)

Bottom Line: The Eddy Current Displacement Sensor (ECDS) is widely used in the Magnetic Suspension Flywheel (MSFW) to measure the tiny clearance between the rotor and the magnetic bearings.Wide clearances must be measured in some new MSFWs recently designed for the different space missions, but the coil diameter is limited by some restrictions.The effectiveness of the linear range extension ability and the dynamic response of the designed ECDS are confirmed by the testing and the applications in the MSFW.

View Article: PubMed Central - PubMed

Affiliation: Science and Technology on Inertial Laboratory, School of Instrumentation Science and Opto-Electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China. fangjiancheng@buaa.edu.cn

ABSTRACT
The Eddy Current Displacement Sensor (ECDS) is widely used in the Magnetic Suspension Flywheel (MSFW) to measure the tiny clearance between the rotor and the magnetic bearings. The linear range of the ECDS is determined by the diameter of its probe coil. Wide clearances must be measured in some new MSFWs recently designed for the different space missions, but the coil diameter is limited by some restrictions. In this paper, a multi-channel ECDS equipped with dual-coil probes is proposed to extend the linear range to satisfy the demands of such MSFWs. In order to determine the best configuration of the dual-coil probe, the quality factors of the potential types of the dual-coil probes, the induced eddy current and the magnetic intensity on the surface of the measuring object are compared with those of the conventional single-coil probe. The linear range of the ECDS equipped with the selected dual-coil probe is extended from 1.1 mm to 2.4 mm under the restrictions without adding any cost for additional compensation circuits or expensive coil materials. The effectiveness of the linear range extension ability and the dynamic response of the designed ECDS are confirmed by the testing and the applications in the MSFW.

No MeSH data available.


Related in: MedlinePlus

The eddy current densities on the surface of the measuring ring. (a) The dual-coil probe with the same direction; (b) The dual-coil probe with the opposite direction; (c) The single coil.
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f10-sensors-12-10693: The eddy current densities on the surface of the measuring ring. (a) The dual-coil probe with the same direction; (b) The dual-coil probe with the opposite direction; (c) The single coil.

Mentions: Because the connection modes of the two coils could not be easily separated in the FEM analysis, the exciting current direction in the two coils is the key factor taken account in the analysis. Combined with the Q-factor calculation results motioned above, the best type dual-coil probe could be defined. As shown in Figure 10, there are the eddy current density distributions on the surface of the measuring object while the different probes are used. The eddy current densities of dual-coil probe with same direction, dual-coil probe with opposite direction and single coil probe are 1.2316 × 105 A/m2, 1.9521 × 105 A/m2 and 1.137 × 105 A/m2, respectively.


A wide linear range Eddy Current Displacement Sensor equipped with dual-coil probe applied in the Magnetic Suspension Flywheel.

Fang J, Wen T - Sensors (Basel) (2012)

The eddy current densities on the surface of the measuring ring. (a) The dual-coil probe with the same direction; (b) The dual-coil probe with the opposite direction; (c) The single coil.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472851&req=5

f10-sensors-12-10693: The eddy current densities on the surface of the measuring ring. (a) The dual-coil probe with the same direction; (b) The dual-coil probe with the opposite direction; (c) The single coil.
Mentions: Because the connection modes of the two coils could not be easily separated in the FEM analysis, the exciting current direction in the two coils is the key factor taken account in the analysis. Combined with the Q-factor calculation results motioned above, the best type dual-coil probe could be defined. As shown in Figure 10, there are the eddy current density distributions on the surface of the measuring object while the different probes are used. The eddy current densities of dual-coil probe with same direction, dual-coil probe with opposite direction and single coil probe are 1.2316 × 105 A/m2, 1.9521 × 105 A/m2 and 1.137 × 105 A/m2, respectively.

Bottom Line: The Eddy Current Displacement Sensor (ECDS) is widely used in the Magnetic Suspension Flywheel (MSFW) to measure the tiny clearance between the rotor and the magnetic bearings.Wide clearances must be measured in some new MSFWs recently designed for the different space missions, but the coil diameter is limited by some restrictions.The effectiveness of the linear range extension ability and the dynamic response of the designed ECDS are confirmed by the testing and the applications in the MSFW.

View Article: PubMed Central - PubMed

Affiliation: Science and Technology on Inertial Laboratory, School of Instrumentation Science and Opto-Electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China. fangjiancheng@buaa.edu.cn

ABSTRACT
The Eddy Current Displacement Sensor (ECDS) is widely used in the Magnetic Suspension Flywheel (MSFW) to measure the tiny clearance between the rotor and the magnetic bearings. The linear range of the ECDS is determined by the diameter of its probe coil. Wide clearances must be measured in some new MSFWs recently designed for the different space missions, but the coil diameter is limited by some restrictions. In this paper, a multi-channel ECDS equipped with dual-coil probes is proposed to extend the linear range to satisfy the demands of such MSFWs. In order to determine the best configuration of the dual-coil probe, the quality factors of the potential types of the dual-coil probes, the induced eddy current and the magnetic intensity on the surface of the measuring object are compared with those of the conventional single-coil probe. The linear range of the ECDS equipped with the selected dual-coil probe is extended from 1.1 mm to 2.4 mm under the restrictions without adding any cost for additional compensation circuits or expensive coil materials. The effectiveness of the linear range extension ability and the dynamic response of the designed ECDS are confirmed by the testing and the applications in the MSFW.

No MeSH data available.


Related in: MedlinePlus