Investigation of the Effect of Bonding Points on Metal Surface-Mounted FBG Sensors for Electric Machines

Alalibo, Belema P.; Cao, Wenping; Gbadebo, Adenowo; Aarniovuori, Lassi; Cai, and Kewei

doi:10.2528/pierc19080806

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…The FFT on the stray flux revealed a significant difference in spectral content, but also a consistency in these differences. For instance, when the motor was run at odd frequencies (5, 15, and 25 Hz), the stray flux under the broken rotor condition consistently showed a significant variation in its time varying amplitude, compared to the variations observed when the motor was run at even frequencies (10,20,and 30 Hz). This behavior may have been due to the forced vibration characteristics of the motor at odd frequencies compared to even frequencies, which would require vibration analysis, which is beyond the scope of this work.…”

Section: Fbg-t Fault Severity Discriminationmentioning

confidence: 94%

“…This is mainly because optical fibers are inherently immune to electromagnetic fields; hence the use of terfenol-D in this research, as shown in Figure 2. Prior to carrying out experiments, the effect of the number of bonding points on the metal surface-mounted FBG sensors was investigated and reported in [20], which took account of the impact of the adhesive used.…”

Section: Basic Fbg Sensing Principlementioning

confidence: 99%

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Short Circuit and Broken Rotor Faults Severity Discrimination in Induction Machines Using Non-invasive Optical Fiber Technology

Alalibo

Cao

2022

Energies

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Multiple techniques continue to be simultaneously utilized in the condition monitoring and fault detection of electric machines, as there is still no single technique that provides an all-round solution to fault finding in these machines. Having various machine fault-detection techniques is useful in allowing the ability to combine two or more in a manner that will provide a more comprehensive application-dependent condition-monitoring solution; especially, given the increasing role these machines are expected to play in man’s transition to a more sustainable environment, where many more electric machines will be required. This paper presents a novel non-invasive optical fiber using a stray flux technique for the condition monitoring and fault detection of induction machines. A giant magnetostrictive transducer, made of terfenol-D, was bonded onto a fiber Bragg grating, to form a composite FBG-T sensor, which utilizes the machines’ stray flux to determine the internal condition of the machine. Three machine conditions were investigated: healthy, broken rotor, and short circuit inter-turn fault. A tri-axial auto-data-logging flux meter was used to obtain stray magnetic flux measurements, and the numerical results obtained with LabView were analyzed in MATLAB. The optimal positioning and sensitivity of the FBG-T sensor were found to be transverse and 19.3810 pm/μT, respectively. The experimental results showed that the FBG-T sensor accurately distinguished each of the three machine conditions using a different order of magnitude of Bragg wavelength shifts, with the most severe fault reaching wavelength shifts of hundreds of picometres (pm) compared to the healthy and broken rotor conditions, which were in the low-to-mid-hundred and high-hundred picometre (pm) range, respectively. A fast Fourier transform (FFT) analysis, performed on the measured stray flux, revealed that the spectral content of the stray flux affected the magnetostrictive behavior of the magnetic dipoles of the terfenol-D transducer, which translated into strain on the fiber gratings.

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Section: Fbg-t Fault Severity Discriminationmentioning

confidence: 94%

Section: Basic Fbg Sensing Principlementioning

confidence: 99%

Short Circuit and Broken Rotor Faults Severity Discrimination in Induction Machines Using Non-invasive Optical Fiber Technology

Alalibo

Cao

2022

Energies

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“…The performance of surface strain sensing using FBG technology can be affected by the utilized bonding material and mounting procedure [41]. Different bonding methods have been explored in literature, ranging from application of cyanoacrylate adhesive and epoxy-resin glue [42], [43] to use of polyamide tape [19], [43]. While the former methods can provide increased rigidity and thus load to sensor transfer, they also impose a generally more complicated installation procedure and are fixed with no flexibility in terms of sensor repositioning and re-application.…”

Section: Fbg Strain Sensing Principlesmentioning

confidence: 99%

Double Fed Induction Generator Shaft Misalignment Monitoring by FBG Frame Strain Sensing

et al. 2020

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This study explores the potential for using FBG strain sensing to enable recognition of the shaft misalignment condition in electric machine drivetrains through observation of machine frame distributed relative strain. The sensing principles, design and installation methods of the proposed technique are detailed in the paper. The scheme was applied on a purpose built wind turbine generator representative laboratory test rig and its performance evaluated in an extensive experimental study involving a range of healthy and misaligned shaft operating conditions. The obtained experimental data demonstrate the reported method's capability to enable recognition of generator shaft misalignment conditions and thus its health monitoring. Finally, it is shown that the thermal variation of the generator frame structure inherent to its operation, combined with the FBG sensor intrinsic thermo-mechanical cross sensitivity, has no detrimental impact on the fidelity and usability of the observed strain measurements.

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“…Based on works from [1][2][3][4][5][6] there are recent suggestions that FBG does possess encouraging potential for sensing applications in non-permanent magnet machines especially, induction machine and hydro generators. Applications in power electronics modules, multipoint voltage sensing and machine mechanical parameter monitoring such as bearings [7][8][9][10][11][12] have also been reported. FBG sensing is based on the variation of the refractive indices of the fibre core and cladding due to variations in some sensed parameter.…”

Section: Introductionmentioning

confidence: 99%

FBG-T Sensor for Non-intrusive Broken Rotor Fault Severity Detection in Induction Machines

Alalibo¹,

Cao²,

Ji³

et al. 2022

Lecture Notes in Electrical Engineering

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Fiber bragg gratings (FBG) as optical sensors continue to gain increasing relevance in sensing and instrumentation owing to their numerous advantages including immunity to electromagnetic interference (EMI). This paper experiments on the use of a giant magnetostrictive material, Terfenol-D bonded to an FBG hereafter called FBG-T to detect external flux from electrical machines in a noninvasive manner. A DC motor and two identically rated three phase induction motors, FBG-T were used for rotor cage damage detection in this work. Further damage to the faulty rotor was carried out to observe if the FBG-T would distinguish severity in machine fault condition. Results show that the more severely faulted machine experienced the most Braggshift of about 20pm more than the healthy machine at 5Hz, compared to the less severely faulted machine which showed about 15pm more than the healthy machine. Another striking observation was the consistency in the distinct and deviant path followed by both faulty motor conditions when compared to the healthy motor. The more severe the rotor damage fault was, the larger the divergence from the healthy motor signature. The results do show that the faulty machine with the broken rotor consistently recorded more Braggshifts than the healthy motor at all frequencies. This resulted in a distinct and aberrant sensing profile which detects the fault in a non-intrusive manner. In addition to observed bragg shifts, divergence levels in grating profile from the healthy reference condition was used to succinctly detect the fault severity in the induction motor condition. This is hugely significant because of the non-intrusive nature of the technique given the ease-of-breakage and the challenges faced when FBG installed in machine stator slots are to be replaced. This technique easily overcomes the inevitable requirements of the offline FBG replacement and its associated economic costs including downtime.

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Investigation of the Effect of Bonding Points on Metal Surface-Mounted FBG Sensors for Electric Machines

Cited by 5 publications

References 24 publications

Short Circuit and Broken Rotor Faults Severity Discrimination in Induction Machines Using Non-invasive Optical Fiber Technology

Short Circuit and Broken Rotor Faults Severity Discrimination in Induction Machines Using Non-invasive Optical Fiber Technology

Double Fed Induction Generator Shaft Misalignment Monitoring by FBG Frame Strain Sensing

FBG-T Sensor for Non-intrusive Broken Rotor Fault Severity Detection in Induction Machines

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