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Hirofumi Akagi - One of the best experts on this subject based on the ideXlab platform.

  • mechanism of Shaft End to End voltage generation by asymmetry in an inverter driven motor
    Electrical Engineering in Japan, 2013
    Co-Authors: Yusuke Asakura, Hirofumi Akagi
    Abstract:

    Summary This paper deals with the Shaft End-to-End voltage resulting from asymmetric stray capacitances in an inverter-driven motor. The origin of the voltage can be any of the following: a ground leakage current, dielectric breakdown in the bearings, and asymmetric stray capacitances on the stator windings. The third origin seems to be related to the differential-mode current, but the details of the relationship have not been clarified. In this study, differential-mode tests are carried out on an ungrounded motor rated at 400 V and 15 kW, and Shaft End-to-End voltage generation by the asymmetric stray capacitances is theoretically discussed. Finally, a winding model is presented for the purpose of understanding the mechanism responsible for the Shaft End-to-End voltage. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 185(1): 48–56, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22415

  • mechanism of Shaft End to End voltage generation by asymmetry in an inverter driven motor
    Ieej Transactions on Industry Applications, 2012
    Co-Authors: Yusuke Asakura, Hirofumi Akagi
    Abstract:

    This paper deals with the Shaft End-to-End voltage resulting from asymmetric stray capacitances in an inverter-driven motor. The origin of the voltage can be any of the following: a ground leakage current, dielectric breakdown in bearings, and asymmetric stray capacitances on stator windings. The third origin seems to be related to the differential-mode current, but the details of the relationship have not been clarified. In this study, differential-mode tests are carried out on an ungrounded motor rated at 400V and 15kW, and the Shaft End-to-End voltage generation by the asymmetric stray capacitances is theoretically discussed. Finaly, a winding model is presented for the purpose of understanding the mechanism responsible for the Shaft End-to-End voltage.

  • identification and discussion of the origin of a Shaft End to End voltage in an inverter driven motor
    IEEE Transactions on Power Electronics, 2010
    Co-Authors: Umar Tabrez Shami, Hirofumi Akagi
    Abstract:

    This paper addresses Shaft End-to-End and Shaft-to-frame voltages that appear in the 400-V 15-kW induction motor driven by a voltage-source pulsewidth modulation inverter. It has been known that an inverter-fed common-mode voltage causes both Shaft voltages. Extensive experiments are performed with an ungrounded motor subjected to a differential-mode voltage. Experimental results show that the differential-mode voltage applied across three-phase, two-phase, or single-phase stator windings also causes a Shaft End-to-End voltage. It is concluded that the combination of a steep change in differential-mode voltage and high-frequency motor asymmetry causes a Shaft End-to-End voltage. A motor model is presented to explain the generation of Shaft End-to-End voltage.

  • experimental discussions on a Shaft End to End voltage appearing in an inverter driven motor
    IEEE Transactions on Power Electronics, 2009
    Co-Authors: Umar Tabrez Shami, Hirofumi Akagi
    Abstract:

    This paper addresses Shaft End-to-End and Shaft-to-frame voltages that appear in the 400-V, 15-kW induction motor driven by a voltage-source pulsewidth modulation (PWM) inverter. A Shaft-to-frame voltage can be observed at either Shaft End with respect to the grounded motor frame. A Shaft End-to-End voltage can be observed as a voltage difference between the Shaft-to-frame voltage at the drive End (DE) and that at the nondrive End (NDE). Experimental waveforms lead to the following interesting observations: motor internal coupling and parasitic capacitance, along with the high-frequency common-mode voltage generated by the PWM inverter, cause a Shaft-to-frame voltage with a peak of 8 V at both DE and NDE. When the Shaft-to-frame voltage at either DE or NDE exceeds a dielectric breakdown voltage of thin bearing lubricating grease films, a Shaft End-to-End voltage with a peak of 2 V and a width of 30 ns occurs along the motor Shaft. This paper makes experimental discussions on the Shaft End-to-End voltage generation. Installing a differential-mode filter and/or a common-mode filter on the motor drive system gives a hint on the mechanisms of the occurrence of the Shaft End-to-End voltage.

Umar Tabrez Shami - One of the best experts on this subject based on the ideXlab platform.

  • identification and discussion of the origin of a Shaft End to End voltage in an inverter driven motor
    IEEE Transactions on Power Electronics, 2010
    Co-Authors: Umar Tabrez Shami, Hirofumi Akagi
    Abstract:

    This paper addresses Shaft End-to-End and Shaft-to-frame voltages that appear in the 400-V 15-kW induction motor driven by a voltage-source pulsewidth modulation inverter. It has been known that an inverter-fed common-mode voltage causes both Shaft voltages. Extensive experiments are performed with an ungrounded motor subjected to a differential-mode voltage. Experimental results show that the differential-mode voltage applied across three-phase, two-phase, or single-phase stator windings also causes a Shaft End-to-End voltage. It is concluded that the combination of a steep change in differential-mode voltage and high-frequency motor asymmetry causes a Shaft End-to-End voltage. A motor model is presented to explain the generation of Shaft End-to-End voltage.

  • experimental discussions on a Shaft End to End voltage appearing in an inverter driven motor
    IEEE Transactions on Power Electronics, 2009
    Co-Authors: Umar Tabrez Shami, Hirofumi Akagi
    Abstract:

    This paper addresses Shaft End-to-End and Shaft-to-frame voltages that appear in the 400-V, 15-kW induction motor driven by a voltage-source pulsewidth modulation (PWM) inverter. A Shaft-to-frame voltage can be observed at either Shaft End with respect to the grounded motor frame. A Shaft End-to-End voltage can be observed as a voltage difference between the Shaft-to-frame voltage at the drive End (DE) and that at the nondrive End (NDE). Experimental waveforms lead to the following interesting observations: motor internal coupling and parasitic capacitance, along with the high-frequency common-mode voltage generated by the PWM inverter, cause a Shaft-to-frame voltage with a peak of 8 V at both DE and NDE. When the Shaft-to-frame voltage at either DE or NDE exceeds a dielectric breakdown voltage of thin bearing lubricating grease films, a Shaft End-to-End voltage with a peak of 2 V and a width of 30 ns occurs along the motor Shaft. This paper makes experimental discussions on the Shaft End-to-End voltage generation. Installing a differential-mode filter and/or a common-mode filter on the motor drive system gives a hint on the mechanisms of the occurrence of the Shaft End-to-End voltage.

Samir Ziada - One of the best experts on this subject based on the ideXlab platform.

  • measurement of high solidity vertical axis wind turbine aerodynamic loads under high vibration response conditions
    Journal of Fluids and Structures, 2012
    Co-Authors: Kevin W Mclaren, S Tullis, Samir Ziada
    Abstract:

    Abstract A series of full-scale experimental wind tunnel tests were performed to determine the aerodynamic loading behaviour on the airfoils of a high solidity, H-type, vertical axis wind turbine. During the course of this investigation, high amplitude vibration of the turbine was observed over a wide range of test conditions. The primary vibration excitation mechanism was resonance of the dominant whirling mode of the turbine with the operating blade pass frequency. In addition, for a significant number of test cases, resonance of the airfoil support struts at higher frequencies was also observed. This large vibration response resulted in conditions that made it difficult or impossible to measure the underlying aerodynamic loading. As a result, in order to gain a greater understanding of the aerodynamic loading, a vibration isolation methodology was developed to remove the effect of vibration from the measured aerodynamic forces on the blades. This included tests with two different support Shaft End conditions over a range of flow velocities from 8 to 11 m/s, and the use of band-stop filtering to remove residual small amplitude vibrations. In this way, an accurate and complete measurement of the aerodynamic loading on the turbine blades could be obtained to better understand the effects of dynamic stall and validate the results of numerical model predictions.

  • vibration response behaviour of a high solidity low rotational velocity vertical axis wind turbine
    ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels Microchannels and Minic, 2010
    Co-Authors: Kevin W Mclaren, S Tullis, Samir Ziada
    Abstract:

    A series of full scale experimental wind tunnel tests were performed to determine the aerodynamic loading behaviour on the airfoils of a high solidity, low rotational velocity, 3 bladed H-type vertical axis wind turbine. The primary vibration response was resonance excitation of the dominant whirling mode of the turbine. However, for a significant number of test cases, resonance behaviour was also observed in the bEnding strains of the airfoil support struts, primarily corresponding to higher natural frequencies. Furthermore, under various test conditions, vibration amplitude within the support struts was observed to change dramatically during a single test run, suggesting that the vibration was jumping between sets of airfoil support struts in a complex beating mode. In order to isolate the numerous vibration excitation and response behaviours, tests were performed over a range of flow velocities from 8 m/s to 11 m/s with two different support Shaft End conditions.

Xiaoyang Xu - One of the best experts on this subject based on the ideXlab platform.

  • bearing dismantling appliance for travelling wheels of monorail passenger train
    2010
    Co-Authors: Xiaoyang Xu
    Abstract:

    The utility model discloses a bearing dismantling appliance for travelling wheels of a monorail passenger train, which is characterized by comprising a manual hydraulic puller, a cross body, pulling claws and a Shaft End inserted head, wherein a helical push-pull rod of the manual hydraulic puller passes through a central threaded hole of the cross body to be connected to the Shaft End inserted head, four Ends of the cross body are respectively connected with a pulling claw, and the heads of the pulling claws are connected with pulling claw tips. The bearing dismantling appliance has the benefits of aiming at the travelling wheels of the monorail passenger train, solving the End-supporting problem of the hollow axle Shaft of the walking wheels of the monorail passenger train by using the Shaft End inserted head and solving the problem of pulling and protecting the bearing and accessories by using the structure of pulling claw tips, as well as achieving the purpose of dismantling the bearing and the accessories slowly in the process of dismantling without causing damage to the axle Shaft, the bearing and a plurality of interrelated parts.

  • bearing dismantling appliance for guide wheels of monorail passenger train
    2010
    Co-Authors: Xiaoyang Xu
    Abstract:

    The utility model discloses a bearing dismantling appliance for guide wheels of a monorail passenger train, which is characterized by comprising a manual hydraulic puller, a cross body, pulling claws and a Shaft End tipped head, wherein a helical push-pull rod of the manual hydraulic puller passes through a central threaded hole of the cross body to be connected to the Shaft End-tipped head, four Ends of the cross body are respectively connected with a pulling claw, and the heads of the pulling claws are connected with movable pulling claw tips. The bearing dismantling appliance has the benefits of: aiming at the guide wheels of the monorail passenger train, solving the End-supporting problem of the irregular axle Shaft of the guide wheels of the monorail passenger train by using the Shaft End tipped head and solving the problem of pulling and protecting the bearing and accessories by using the structure of movable pulling claw tips, as well as achieving the purpose of dismantling the bearing and the accessories slowly in the process of dismantling without causing damage to the axle Shaft, the bearing and a plurality of interrelated parts.

Kevin W Mclaren - One of the best experts on this subject based on the ideXlab platform.

  • measurement of high solidity vertical axis wind turbine aerodynamic loads under high vibration response conditions
    Journal of Fluids and Structures, 2012
    Co-Authors: Kevin W Mclaren, S Tullis, Samir Ziada
    Abstract:

    Abstract A series of full-scale experimental wind tunnel tests were performed to determine the aerodynamic loading behaviour on the airfoils of a high solidity, H-type, vertical axis wind turbine. During the course of this investigation, high amplitude vibration of the turbine was observed over a wide range of test conditions. The primary vibration excitation mechanism was resonance of the dominant whirling mode of the turbine with the operating blade pass frequency. In addition, for a significant number of test cases, resonance of the airfoil support struts at higher frequencies was also observed. This large vibration response resulted in conditions that made it difficult or impossible to measure the underlying aerodynamic loading. As a result, in order to gain a greater understanding of the aerodynamic loading, a vibration isolation methodology was developed to remove the effect of vibration from the measured aerodynamic forces on the blades. This included tests with two different support Shaft End conditions over a range of flow velocities from 8 to 11 m/s, and the use of band-stop filtering to remove residual small amplitude vibrations. In this way, an accurate and complete measurement of the aerodynamic loading on the turbine blades could be obtained to better understand the effects of dynamic stall and validate the results of numerical model predictions.

  • vibration response behaviour of a high solidity low rotational velocity vertical axis wind turbine
    ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels Microchannels and Minic, 2010
    Co-Authors: Kevin W Mclaren, S Tullis, Samir Ziada
    Abstract:

    A series of full scale experimental wind tunnel tests were performed to determine the aerodynamic loading behaviour on the airfoils of a high solidity, low rotational velocity, 3 bladed H-type vertical axis wind turbine. The primary vibration response was resonance excitation of the dominant whirling mode of the turbine. However, for a significant number of test cases, resonance behaviour was also observed in the bEnding strains of the airfoil support struts, primarily corresponding to higher natural frequencies. Furthermore, under various test conditions, vibration amplitude within the support struts was observed to change dramatically during a single test run, suggesting that the vibration was jumping between sets of airfoil support struts in a complex beating mode. In order to isolate the numerous vibration excitation and response behaviours, tests were performed over a range of flow velocities from 8 m/s to 11 m/s with two different support Shaft End conditions.