Analysis of torsional torques in starting of large squirrel cage induction motors

Shaltout, A.

doi:10.1109/60.282484

Cited by 49 publications

(22 citation statements)

References 6 publications

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“…This gives s × f s = 23.6 Hz, which is the same as the natural torsional frequency of the mechanical system calculated by Eq. (5) [3,7]. However, as the motor speed continues to grow, the slip frequency departs from the natural frequency and the shaft torque starts to decay.…”

Section: Sinusoidal Supplymentioning

confidence: 92%

“…As shown in Figure 3, these currents produce the following MMFs in the motor air gap The speed frequency component has a small magnitude and can usually be neglected [3]. Nevertheless, it is the SFT that is responsible for the high shaft torque oscillations.…”

Section: Sinusoidal Supplymentioning

confidence: 98%

“…The equation of motion of the rotating mass including the torsional dynamics of the shaft is given by [3]: where θ l is the load angular position, θ m is the motor angular position, ω l is the load angular speed of rotation, K s is the stiffness coefficient of the motor shaft, H m is the motor inertia, D m is the viscous friction coefficient of the motor, D ml is the mutual damping coefficient, H l is the load inertia, D l is the viscous friction coefficient of the load shaft, and T l is the load torque.…”

Section: Model Of Large Motor Systemmentioning

confidence: 99%

“…Reduction of the shaft torque oscillations during startup with an autotransformer or star/delta switching has been achieved by the proper choice of the switching instant, as improper switching may reinitiate the shaft torque oscillations [3].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Cost-Effective Control Scheme for Reduction of Torsional Torque Oscillations in Starting Large Induction Motors

Abdel-Rahim

Shaltout

2006

Electric Power Components and Systems

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This article presents a cost-effective variable frequency drive for starting and operating large three-phase squirrel cage induction motors. The proposed drive employs the constant V/F control scheme, which regulates the rotor frequency such that it is always kept below a predetermined value. This has the effect of drastically reducing the motor shaft torque oscillations and significantly limiting the maximum value of the motor line current. In addition to its simplicity and hence cost-effectiveness, the proposed scheme is shown to be capable of (i) reducing the shaft torque oscillations to approximately 22% of that of the direct on-line start of the large motor, and (ii) limiting the motor line current to approximately 36% of that of the direct on-line start value.

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Section: Sinusoidal Supplymentioning

confidence: 92%

Section: Sinusoidal Supplymentioning

confidence: 98%

Section: Model Of Large Motor Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cost-Effective Control Scheme for Reduction of Torsional Torque Oscillations in Starting Large Induction Motors

Abdel-Rahim

Shaltout

2006

Electric Power Components and Systems

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“…The starting transient behavior for large induction motors has been studied extensively [20]. A simulation is used in this chapter to explain observed behavior on the SENECA.…”

Section: Induction Motor Simulationmentioning

confidence: 99%

Diagnostic indicators for shipboard systems using non-intrusive load monitoring

DeNucci

Cox

Leeb

et al. 2005

IEEE Electric Ship Technologies Symposium, 2005.

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Field studies have demonstrated that the Non-Intrusive Load monitor (NILM) can provide real-time indication of the condition of electro-mechanical systems on board naval vessels. Results from data collected from engineering systems on board USCGC SENECA , a 270-foot U.S. Coast Guard cutter, indicate that the NILM can effectively identify faults, failures and deviations from normal operating conditions on numerous shipboard engineering systems.Data collected from the sewage system identified metrics that can be applied, for example, to cycling systems (high pressure air, hydraulic systems, etc.) to differentiate between periods of heavy usage and fault conditions. Sewage system variability and randomness was minimized by employing a MATLAB simulation designed to permit exploration of system behavior that might not have been exposed during other conditions. Simulation data suggests that the presence, location and magnitude of a spike in the pump run distribution indicated the presence of a leak. Data from the actual shipboard system, when subjected to a quantifiable leak, displayed the same behavior.Data collected from the Auxiliary Seawater (ASW) System indicated that the NILM is able to predict the failure of a flexible coupling linking the pump and motor components. The ASW motor-pump system was modeled using a 5 th order induction motor simulation to explore the electro-mechanical relationships between the motor, coupling and pump. Changes to the mechanical parameters of the coupling were captured in the electrical signature of the motor in both the simulation and shipboard data.Frequency domain analysis of the ASW System data also suggested that the clogging of a heat exchanger on a critical shipboard system can be identified with the NILM, although the extent of diagnosis is dependent on the system flow patterns. Further development of hardware and software, along with continued research into the behavior of shipboard systems, will allow the NILM to augment existing monitoring systems and potentially serve as a stand-alone indicator of critical system performance.

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A dynamic model for the investigation of twisting effect in long flux‐ switchingPMmotors inESPs

Bafghi

Vahedi

Mohammad‐Alikhani

et al. 2021

Int Trans Electr Energ Syst

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Shaft twisting occurs along the length of electric motors rotors. The twisting depends on the shaft properties and the transmitted torque. In Electrical Submersible Pumps, due to the high ratio of length to the diameter of the motor and the high load torque, the twisting effect occurs significantly. Thus, when such a condition emerges for an electric motor, the electromagnetic torque is not uniformly produced along the motor length, since shaft twisting results in rotor position variation with respect to the stator. Therefore, the twisting and

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Analysis of torsional torques in starting of large squirrel cage induction motors

Cited by 49 publications

References 6 publications

Cost-Effective Control Scheme for Reduction of Torsional Torque Oscillations in Starting Large Induction Motors

Cost-Effective Control Scheme for Reduction of Torsional Torque Oscillations in Starting Large Induction Motors

Diagnostic indicators for shipboard systems using non-intrusive load monitoring

A dynamic model for the investigation of twisting effect in long flux‐ switchingPMmotors inESPs

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