The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
J Ponsllinares - One of the best experts on this subject based on the ideXlab platform.
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reliable detection of inDuction motor rotor faults under the rotor axial Air Duct influence
IEEE Transactions on Industry Applications, 2014Co-Authors: Chanseung Yang, Taejune Kang, Doosoo Hyun, Sang Bin Lee, Jose A Antoninodaviu, J PonsllinaresAbstract:Axial cooling Air Ducts in the rotor of large inDuction motors are known to produce magnetic asymmetry and can cause steady-state current or vibration spectrum analysis based fault detection techniques to fail. If the number of axial Air Ducts and that of poles are identical, frequency components that overlap with that of rotor faults can be produced for healthy motors. False positive rotor fault indication due to axial Ducts is a common problem in the field that results in unnecessary maintenance cost. However, there is currently no known test method available for distinguishing rotor faults and false indications due to axial Ducts other than offline rotor inspection or testing. Considering that there is no magnetic asymmetry under high slip conditions due to limited flux penetration into the rotor yoke, the detection of broken bars under the start-up transient is investigated in this paper. A wavelet-based detection method is proposed and verified on custom-built lab motors and 6.6-kV motors misdiagnosed with broken bars via steady-state spectrum analysis. It is shown that the proposed method provides the reliable detection of broken bars under the start-up transient independent of axial Duct influence.
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reliable detection of inDuction motor rotor faults under the rotor axial Air Duct influence
Energy Conversion Congress and Exposition, 2013Co-Authors: Chanseung Yang, Taejune Kang, Doosoo Hyun, Sang Bin Lee, Jose A Antoninodaviu, J PonsllinaresAbstract:Axial cooling Air Ducts in the rotor of large inDuction motors are known to produce magnetic asymmetry, and can cause steady state current or vibration spectrum analysis based fault detection techniques to fail. If the number of axial Air Ducts and poles are identical, frequency components that overlap with that of rotor faults can be produced for healthy motors. False positive rotor fault indication due to axial Ducts is a common problem in the field that results in unnecessary maintenance cost. However, there is currently no known test method available for distinguishing rotor faults and false indications due to axial Ducts other than off-line rotor inspection or testing. Considering that there is no magnetic asymmetry under high slip conditions due to limited flux penetration into the rotor yoke, detection of broken bars under the startup transient is investigated in this paper. A wavelet-based detection method is proposed and verified on custom-built lab motors and 6.6 kV motors misdiagnosed with broken bars via steady state spectrum analysis. It is shown that the proposed method provides reliable detection of broken bars under the startup transient independent of axial Duct influence.
J S Saini - One of the best experts on this subject based on the ideXlab platform.
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heat transfer and friction factor correlations for a solar Air heater Duct roughened artificially with v ribs with symmetrical gaps
Experimental Thermal and Fluid Science, 2016Co-Authors: Rajesh Maithani, J S SainiAbstract:Abstract An experimental study has been carried out for enhancement of heat transfer coefficient of a solar Air heater having roughened Air Duct artificially roughened in the form of V-ribs with symmetrical gaps as turbulence promoter. In present work an experimental investigation of heat transfer and friction of artificial roughness in the form of V-ribs with symmetrical gaps were investigated. The investigation encompassed Reynolds number ( Re ) ranging from 4000 to 18,000, Number of gaps ( N g ) values of 1–5, relative gap width ( g / e ) values of 1–5, relative roughness pitch ( P / e ) values of 6–12, angle of attack ( α ) range of 30–75° and relative roughness height ( e / D ) values of 0.043. For Nusselt number ( Nu ), the maximum enhancement of the order of 3.6 times that of smooth Duct has been obtained, similarly friction factor ( f ) also increases by 3.67 folds of that of the smooth Duct. The rib parameters corresponding to maximum increase in Nu and f were N g = 3, g / e = 4, P / e = 10 and α = 60°. Based on the experimental data, correlations for Nu and f have been developed as function of roughness parameters of V-ribs with symmetrical gap and flow Reynolds number.
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use of turbulators for heat transfer augmentation in an Air Duct a review
Renewable Energy, 2014Co-Authors: Tabish Alam, R P Saini, J S SainiAbstract:Energy and material saving considerations, as well as economic incentives, have led toward making effort for producing more efficient heat exchange equipment such as solar Air heaters, heat exchangers. In order to enhance the heat transfer rate to flowing Air in the Duct of solar Air heater and heat exchangers various turbulence generators viz. ribs, baffles and delta winglets are considered as an effective technique. Investigators reported on various turbulators in literature for studying heat transfer and friction characteristics in a Duct of solar Air heaters and heat exchangers. An attempt has been made in this paper to carry out an extensive literature review of various turbulators investigated for enhancing heat transfer and friction in solar Air heaters and heat exchangers. The correlations developed for heat transfer and friction factor in solar Air heaters and heat exchangers by various investigators have been presented and reviewed.
Yi Jiang - One of the best experts on this subject based on the ideXlab platform.
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Performance analysis of a new kind of heat pump-driven outdoor Air processor using solid desiccant
Renewable Energy, 2013Co-Authors: Xiaohua Liu, Yi JiangAbstract:Abstract A new type of outdoor Air dehumidification processor using solid desiccant is proposed, in which a heat pump and square desiccant plates are combined. Each desiccant plate consists of an Air channel with a honeycomb structure that is coated with desiccant material. The square desiccant plates change positions between the processed Air Duct for dehumidification and the regenerated Air Duct for regeneration. The cooling capacity of the heat pump is utilized to cool the processed Air, and the exhaust heat of the heat pump is used to provide regenerative heat to the desiccant. Several stages can be combined together to gain higher efficiency. The proposed desiccant dehumidifier can achieve a low humidity ratio of the supplied Air and provides low-temperature regeneration. A mathematical model is established to predict the performance of this desiccant processor, and the model shows good agreement with the experimental results. The factors that influence the performance of the processor are then analyzed in order to maximize performance. The simulation results show that the proposed desiccant processor provides regeneration at a low temperature (40–50 °C), and the COP can surpass 4.0 at different processed Air inlet states.
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performance optimization of heat pump driven liquid desiccant dehumidification systems
Energy and Buildings, 2012Co-Authors: Tao Zhang, Yi JiangAbstract:Heat pump driven liquid desiccant dehumidification (HPLD) devices, in which both the cooling capacity from an evaporator and heat from a condenser are utilized, have been developing rapidly in recent years. Because the amount of heat from the condenser is usually more than required for desiccant regeneration, the key to improve the performance of these systems involves effectively exhausting the extra heat. In this paper, two different methods for removing the extra heat are analyzed: adding an Air-cooled assistant condenser in either the inlet or outlet of the regeneration Air Duct, and utilizing a water-cooled assistant condenser that uses cooled water from evaporation of the exhaust Air. These handling processes were compared in terms of their HPLD performance under various operating conditions. Devices using an Air-cooled or water-cooled assistant condenser showed better performance than a basic system without an assistant condenser. For systems with an Air-cooled assistant condenser, the location of the condenser rarely affected the performance: COPsys was an average of about 18% higher than that of the basic system. The system with the water-cooled condenser performed the best out of all the investigated systems: COPsys was about 35% higher than that of the basic system.
Chanseung Yang - One of the best experts on this subject based on the ideXlab platform.
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reliable detection of inDuction motor rotor faults under the rotor axial Air Duct influence
IEEE Transactions on Industry Applications, 2014Co-Authors: Chanseung Yang, Taejune Kang, Doosoo Hyun, Sang Bin Lee, Jose A Antoninodaviu, J PonsllinaresAbstract:Axial cooling Air Ducts in the rotor of large inDuction motors are known to produce magnetic asymmetry and can cause steady-state current or vibration spectrum analysis based fault detection techniques to fail. If the number of axial Air Ducts and that of poles are identical, frequency components that overlap with that of rotor faults can be produced for healthy motors. False positive rotor fault indication due to axial Ducts is a common problem in the field that results in unnecessary maintenance cost. However, there is currently no known test method available for distinguishing rotor faults and false indications due to axial Ducts other than offline rotor inspection or testing. Considering that there is no magnetic asymmetry under high slip conditions due to limited flux penetration into the rotor yoke, the detection of broken bars under the start-up transient is investigated in this paper. A wavelet-based detection method is proposed and verified on custom-built lab motors and 6.6-kV motors misdiagnosed with broken bars via steady-state spectrum analysis. It is shown that the proposed method provides the reliable detection of broken bars under the start-up transient independent of axial Duct influence.
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reliable detection of inDuction motor rotor faults under the rotor axial Air Duct influence
Energy Conversion Congress and Exposition, 2013Co-Authors: Chanseung Yang, Taejune Kang, Doosoo Hyun, Sang Bin Lee, Jose A Antoninodaviu, J PonsllinaresAbstract:Axial cooling Air Ducts in the rotor of large inDuction motors are known to produce magnetic asymmetry, and can cause steady state current or vibration spectrum analysis based fault detection techniques to fail. If the number of axial Air Ducts and poles are identical, frequency components that overlap with that of rotor faults can be produced for healthy motors. False positive rotor fault indication due to axial Ducts is a common problem in the field that results in unnecessary maintenance cost. However, there is currently no known test method available for distinguishing rotor faults and false indications due to axial Ducts other than off-line rotor inspection or testing. Considering that there is no magnetic asymmetry under high slip conditions due to limited flux penetration into the rotor yoke, detection of broken bars under the startup transient is investigated in this paper. A wavelet-based detection method is proposed and verified on custom-built lab motors and 6.6 kV motors misdiagnosed with broken bars via steady state spectrum analysis. It is shown that the proposed method provides reliable detection of broken bars under the startup transient independent of axial Duct influence.
R P Saini - One of the best experts on this subject based on the ideXlab platform.
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use of turbulators for heat transfer augmentation in an Air Duct a review
Renewable Energy, 2014Co-Authors: Tabish Alam, R P Saini, J S SainiAbstract:Energy and material saving considerations, as well as economic incentives, have led toward making effort for producing more efficient heat exchange equipment such as solar Air heaters, heat exchangers. In order to enhance the heat transfer rate to flowing Air in the Duct of solar Air heater and heat exchangers various turbulence generators viz. ribs, baffles and delta winglets are considered as an effective technique. Investigators reported on various turbulators in literature for studying heat transfer and friction characteristics in a Duct of solar Air heaters and heat exchangers. An attempt has been made in this paper to carry out an extensive literature review of various turbulators investigated for enhancing heat transfer and friction in solar Air heaters and heat exchangers. The correlations developed for heat transfer and friction factor in solar Air heaters and heat exchangers by various investigators have been presented and reviewed.
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development of correlations for nusselt number and friction factor for solar Air heater with roughened Duct having arc shaped wire as artificial roughness
Solar Energy, 2008Co-Authors: S K Saini, R P SainiAbstract:An experimental study has been carried out for enhancement of heat transfer coefficient of a solar Air heater having roughened Air Duct provided with artificial roughness in the form of arc-shape parallel wire as roughness element. Increment in friction factor by provided with such artificial roughness elements has also been studied. The effect of system parameters such as relative roughness height (e/d) and arc angle (α/90) have been studied on Nusselt number (Nu) and friction factor (f) with Reynolds number (Re) varied from 2000 to 17000. Considerable enhancement in heat transfer coefficient has been achieved with such roughness element. Using experimental data correlations for Nusselt number and friction factor have also been developed for such solar Air heaters, which gives a good agreement between predicted values and experimental values of Nusselt number and friction factor.