Analytical modeling of eddy current brakes with the application of time varying magnetic fields

Karakoc, Kerem; Suleman, Afzal; Park, Edward J.

doi:10.1016/j.apm.2015.07.006

Cited by 42 publications

(30 citation statements)

References 27 publications

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“…With the proper placement of PPA points, a significant increase in braking is obtained. Karakoc [33] also mention that the increase in braking torque due to changes from DC power sources to AC occurs at all speed variations. The improvement at high speeds is wider than at low.…”

Section: Unipolar Axial Ecbmentioning

confidence: 99%

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Mini review on the design of axial type eddy current braking technology

Waloyo¹,

Ubaidillah²,

Tjahjana³

et al. 2019

IJPEDS

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Eddy Current Brake (ECB) is a type of electric braking that uses eddy current to produce braking forces. This article delivers a solid review of the design of Axial ECB, which is very promising for an alternative braking system. Several types of axial ECB are classified and named as a single disk, double disk, and unipolar model. The classification of axial ECB is based on the design of coil placement, which induces axial area of the disk as well as the electromagnet source. A potential issue for the development of axial ECB is also discussed to explore the braking performance improvement of the axial type ECB. It was highlighted that research on how to change the direction of magnetic field vectors by changing the shape of the pole-shoe on the electromagnetic ECB in axial type has not been widely studied. Therefore, this issue would be interesting for future investigation.

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Section: Unipolar Axial Ecbmentioning

confidence: 99%

“…The main problem with ECB braking is the amount of braking that is proportional to the vehicle's speed, even at zero speed, there is no braking. To overcome this, AC power is used [31][32][33]. In the conductor, addition of different metal alloy elements to the conductor produces different performance [34].…”

Section: Unipolar Axial Ecbmentioning

confidence: 99%

Mini review on the design of axial type eddy current braking technology

Waloyo¹,

Ubaidillah²,

Tjahjana³

et al. 2019

IJPEDS

View full text Add to dashboard Cite

show abstract

“…where E is the electric field vector, H is the magnetic field strength vector, D is the displacement flux density vector, B is the magnetic flux density vector, ε is the electric permittivity and µ is the magnetic permeability used to describe the electro-magnetic field in terms of sources [27,28]. These equations are written in vector notation and in differential form as:…”

Section: Basic Physical Background For Modelling Ecsmentioning

confidence: 99%

“…Using a combination of ECS and optical sensors, Guru et al [25] instrumented a low pressure turbine stage of a developmental aero engine to monitor blade vibrations during engine tests. In terms of analytical modelling of eddy current fields, Karakoc et al [26,27] derived an analytical model of an eddy current brake ( ECB) under time varying magnetic fields, and investigated the effect of the time varying field on the braking torque. To predict small fatigue cracks, Rosell and Person [28] performed an eddy current contactless inspection based on a finite element model and experiments.…”

Section: Introductionmentioning

confidence: 99%

Modelling and experimental validation of active and passive eddy current sensors for blade tip timing

Jamia

Friswell

El-Borgi

et al. 2019

Sensors and Actuators A: Physical

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To monitor the vibration of blades in rotating machinery, the contactless method called Blade Tip Timing (BTT) is widely used. Blade vibration and clearance are important diagnostic features for condition monitoring, including the detection of blade cracks. To perform the BTT technique, optical sensors were widely used by industry due to their high accuracy, but the main drawback of these systems is their low tolerance to the presence of contaminants. To overcome this downside, eddy current sensors are a good alternative for health monitoring applications in gas turbines due to their insensitivity to contaminants and debris. This type of sensor has been used by many researchers, predominantly on the experimental side to investigate BTT systems and there is a lack of modelling to support the measurement system design. This paper fills the gap between experiments and modelling for the particular case of a blade rotating past eddy current sensors. Hence the novelty of this paper is the simulation of the BTT application using detailed quasi-static finite element models of the electromagnetic field to estimate the outputs from active and passive eddy current sensors. A test rig composed of a bladed disk with 12 blades clamped to a rotating shaft was designed and manufactured in order to validate the proposed models with experimental measurements. Finally, a parametric study is presented to show the effect of the blade tip clearance and the rotational speed on the accuracy of the BTT measurement. This leads to better understanding of the sources of error in the time of arrival of the blades passing the sensor and hence insight into the blade vibration measurement accuracy.

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“…Source: Inspired by Pohl et al 33 Maxwell's equations (equations (1)-(4)) along with constitutive relations (equations (5) and (6)) and the magnetic and electric material properties of the target are used to describe the electro-magnetic field in terms of sources as 31,32 r 3 H = J + ∂D ∂t ð1Þ…”

Section: Governing Equations For Modeling Of Ecsmentioning

confidence: 99%

Simulating eddy current sensor outputs for blade tip timing

Jamia

Friswell

El-Borgi

et al. 2018

Advances in Mechanical Engineering

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Blade tip timing is a contactless method used to monitor the vibration of blades in rotating machinery. Blade vibration and clearance are important diagnostic features for condition monitoring, including the detection of blade cracks. Eddy current sensors are a practical choice for blade tip timing and have been used extensively. As the data requirements from the timing measurement become more stringent and the systems become more complicated, including the use of multiple sensors, the ability to fully understand and optimize the measurement system becomes more important. This requires detailed modeling of eddy current sensors in the blade tip timing application; the current approaches often rely on experimental trials. Existing simulations for eddy current sensors have not considered the particular case of a blade rotating past the sensor. Hence, the novel aspect of this article is the development of a detailed quasi-static finite element model of the electromagnetic field to simulate the integrated measured output of the sensor. This model is demonstrated by simulating the effect of tip clearance, blade geometry, and blade velocity on the output of the eddy current sensor. This allows an understanding of the sources of error in the blade time of arrival estimate and hence insight into the accuracy of the blade vibration measurement.

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Analytical modeling of eddy current brakes with the application of time varying magnetic fields

Cited by 42 publications

References 27 publications

Mini review on the design of axial type eddy current braking technology

Mini review on the design of axial type eddy current braking technology

Modelling and experimental validation of active and passive eddy current sensors for blade tip timing

Simulating eddy current sensor outputs for blade tip timing

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