Inductive sensor

About: Inductive sensor is a research topic. Over the lifetime, 2282 publications have been published within this topic receiving 21984 citations.

A novel dual modality sensor with sensitivities to permittivity and conductivity

Abstract: In this paper, an electromagnetic (EM) sensor which can operate simultaneously in capacitive and inductive modalities is developed, and a novel measurement strategy is proposed accordingly. The sensor is composed of two planar spiral coils with large track width, which promotes its capacitive mode. The capacitive coupling is measured in common mode while the inductive coupling is measured in differential mode. In capacitive mode, the sensor is sensitive to the dielectric material distribution, i.e. changes in permittivity; while in inductive mode, it is sensitive to magnetically permeable material and electrically conductive material. Furthermore, it is demonstrated that the sensor can simultaneously measure dielectric and conductive materials. This novel sensor has been designed and implemented. Experimental results verified its effectiveness in dual modality measurement.

Design, realization and field results of an inductive casing collar locator

Abstract: During well logging operations, the depth of a logging tool is usually obtained from measuring the length of the wireline cable that suspends the tool in the well. In some cases, a secondary depth reference is obtained by detecting the collars along the casing pipe which lines the well. For small, untethered sensor platforms neither method is practical. This paper describes an inductive sensor which detects the fine gap on the inside of the casing where two pipe joints come together within a collar. The detector consists of two identical short solenoid coils with a common axis. A wired prototype tool was designed, built and tested in the field. Results from the field trial show clear a signal for the casing collars and are agreement with the results from simulations. The signal trend is in agreement with pipe inspection trends published in the literature.

Counting rectangular objects on conveyors using machine vision

Abstract: Counting the number of objects that are transported on a conveyor belt is frequently encountered in production facilities, airports or post offices. Although most of these tasks may usually be solved by using common photoelectric or inductive sensors, there are cases when objects have to be counted using more complex sensing systems based on machine vision. In this paper, an image-processing algorithm for segmenting, detecting and counting rectangular objects which are being transported on a conveyor belt is presented. The method is specifically designed to detect rectangular objects that can be partly occluded. The application is implemented using OpenCV/C++ library. Two different test scenarios are analyzed in the paper. Experimental results suggest that the proposed method has promising accuracy and it is applicable in real-world applications.

Modelling and Measurement of Magnetically Soft Nanowire Arrays for Sensor Applications.

Abstract: Soft magnetic wires and microwires are currently used for the cores of magnetic sensors. Due to their low demagnetization, they contribute to the high sensitivity and the high spatial resolution of fluxgates, Giant Magnetoimpedance (GMI), and inductive sensors. The arrays of nanowires can be prepared by electrodeposition into predefined pores of a nanoporous polycarbonate membrane. While high coercivity arrays with square loops are convenient for information storage and for bistable sensors such as proximity switches, low coercivity cores are needed for linear sensors. We show that coercivity can be controlled by the geometry of the array: increasing the diameter of nanowires (20 µm in length) from 30 nm to 200 nm reduced the coercivity by a factor of 10, while the corresponding decrease in the apparent permeability was only 5-fold. Finite element simulation of nanowire arrays is important for sensor development, but it is computationally demanding. While an array of 2000 wires can be still modelled in 3D, this is impossible for real arrays containing millions of wires. We have developed an equivalent 2D model, which allows us to solve these large arrays with acceptable accuracy. Using this tool, we have shown that as a core of magnetic sensors, nanowires are efficiently employed only together with microcoils with diameter comparable to the nanowire length.

Investigation of PCB-based Inductive Sensors Orientation for Corona Partial Discharge Detection

Abstract: This paper presents an experimental investigation of two different printed circuit board (PCB) inductive sensors, with meander and non-spiral shapes, to assess their capabilities and best orientation for corona partial discharge (PD) detection. First, simulations with the Ansys HFSS software are performed in order to evaluate the equivalent electrical circuit of the two sensors and their 2d radiation patterns. The meander sensors presented a resonant frequency of 600 MHz, while it was around 1.1 GHz for the non-spiral. The 2d radiation pattern showed that better sensitivity is achieved when the inductive sensor is oriented 90 degrees with respect to the PD source. Experimental tests showed a peak-to-peak voltage of the PD signal detected by both sensors of around 14 mV when the orientation was 90 degrees with a main frequency around 35 MHz. The peak-to-peak voltage dropped to about 5.4 mV and 6.9 mV for the meander and the non-spiral sensors, respectively, with a main frequency of about 33.5 MHz, when the orientation was 0 degrees. The obtained PRPD patterns and the PD signal shapes were quite similar to those provided by a High-Frequency Current Transformer (HFCT) commercial sensor.