Possible errors in measurement of air-gap torque pulsations of induction motors

Hsu, J.S.; Woodson, H.H.; Weldon, W.F.

doi:10.1109/60.124561

Cited by 32 publications

(7 citation statements)

References 10 publications

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“…Likewise, the same procedure applies to the negative sequence circuit shown in Fig.2 in which the rotor resistance is expressed by the rotor resistance R2 in series with an another variable resistance (2) In these figures, s refers to the slip, Rl and Xl are the stator resistance and reactance, R2 and X2 the rotor resistance and Copyright Notice: 978-1-4673-6008-11111$31.00 ©20 12 IEEE reactance, Xm the magnetizing reactance, Ip and In the positive and negative-sequence currents, Vp and Vn the positive-and negative-sequence voltages at the motor terminals, and Vp2 and Vn2 the voltages across the variable resistances of the positive-and negative-sequence equivalent circuits. To facilitate our analysis, the following simplifying assumptions have been made: (1) All the elements in Fig.…”

Section: A Motor Modelmentioning

confidence: 97%

Analytical modeling of pulsating torques of induction motors caused by supply voltage unbalance

Wang

Lee

Sung

2011

2011 International Conference &Amp; Utility Exhibition on Power and Energy Systems: Issues and Prospects for Asia (ICUE)

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Voltage unbalance is frequently encountered in a low voltage AC power network to which many three-phase loads are connected. Pulsating torque of IMs caused by voltage unbalance is well known to electrical engineers, and it can easily be simulated by a computer program or measured from laboratory experimental setups. However, analytical models that clearly interpret the physical mechanism linking the pulsating torque and voltage unbalance are not found in literature. In this paper, we develop an analytical model of pulsating torque produced by an 1M under voltage unbalance. The amplitude of the pulsating torque is explicitly expressed as a function of the voltage unbalance factor, i.e., the ratio of the negative-to positive-sequence voltage components. The illustrated examples are analyzed by the proposed analytical model, and validated by results obtained from simulation using the universal machine module of the EMTP.

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Section: A Motor Modelmentioning

confidence: 97%

Analytical modeling of pulsating torques of induction motors caused by supply voltage unbalance

Wang

Lee

Sung

2011

2011 International Conference &Amp; Utility Exhibition on Power and Energy Systems: Issues and Prospects for Asia (ICUE)

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“…The double slip frequency torque indicates an unbalanced rotor. However, once the leakage reactances and magnetic paths of the three phases become asymmetrical, errors are induced and the calculation of air gap torque as in ( 11) is no longer accurate [ 40).…”

Section: E Airgap Torque Monitoringmentioning

confidence: 99%

Monitoring and damping unbalanced magnetic pull due to eccentricity fault in induction machines: A review

Salah

Guo

Dorrell

2017

2017 20th International Conference on Electrical Machines and Systems (ICEMS)

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Condition monitoring can diagnose the inception of fault mechanisms in induction motors, thus avoiding failure and expensive repairs. Therefore, there is a strong need to develop an efficient condition monitoring. The main target is to achieve a relatively low cost and/or non-invasive system which is still powerful in terms of monitoring for online detection of developing faults. The presented paper addresses rotor eccentricity faults and studies conventional monitoring techniques for induction motors. In order to reduce the unbalanced magnetic pull (UMP) in case of an eccentric rotor, the eccentricitygenerated additional airgap flux waves should be reduced. The radial forces in an induction motor are calculated, and the characteristics of unbalanced magnetic pull are described. Index Terms-condition monitoring, eccentric rotor, induction machines, unbalanced magnetic pull (UMP). Bent rotor Bearing wear Misalignment Detections Methods Stato1• current Axial flux Vibration Torq uc, speed Axial flux Stator current Stator current Vibration Stator current Vibration Axial flux

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“…This means the double slip frequency torque indicates an unbalanced rotor cage. However, once the leakage reactances and magnetic paths of the three phases become asymmetrical, errors are induced and the calculation of air gap torque as in (11) is no longer accurate [46].…”

Section: E Airgap Torque Monitoringmentioning

confidence: 99%

Monitoring and Damping UMP Due Eccentricity Fault in Induction Machines: A Review

Salah

Dorrel

Guo

2016

2016 International Conference of Asian Union of Magnetics Societies (ICAUMS)

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Three-phase induction machines are reliable and widely used in industrial plants. Efficient condition monitoring can diagnose the inception of fault mechanisms in induction motors thus avoiding failure and expensive repairs. Therefore, there is a strong need to develop a more efficient condition monitoring. The main target is to achieve a relatively low cost and/or non-invasive system which is still powerful in terms of monitoring for online detection of developing faults. In order to reduce the unbalanced magnetic pull (UMP) in case of an eccentric rotor, the eccentricity-generated additional airgap flux waves should be reduced. The present paper addresses rotor eccentricity faults and studies conventional monitoring techniques for induction motors. The radial forces in an induction motor are calculated. In addition, the characteristics of UMP in induction machines are stated.

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Possible errors in measurement of air-gap torque pulsations of induction motors

Cited by 32 publications

References 10 publications

Analytical modeling of pulsating torques of induction motors caused by supply voltage unbalance

Analytical modeling of pulsating torques of induction motors caused by supply voltage unbalance

Monitoring and damping unbalanced magnetic pull due to eccentricity fault in induction machines: A review

Monitoring and Damping UMP Due Eccentricity Fault in Induction Machines: A Review

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