Journal ArticleDOI
Unbalanced magnetic pull in a 6-pole induction motor
M. Bradford
- Vol. 115, Iss: 11, pp 1619-1627
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TLDR
Comparisons between measurements and calculations show that most existing theories inaccurately predict the magnitude of transient unbalanced magnetic pull during starting, the effect of slotting and saturation, theeffect of a cage rotor, and the action of load currents.Abstract:
A 6-pole 10kW induction motor has been specially constructed for a comprehensive series of steady-state and transient measurements of the magnitude of unbalanced magnetic pull resulting from an eccentric air gap. These measurements have shown that unbalanced magnetic pull is critically dependent on Saturation of the magnetic circuit, and that the magnitude in the cage-rotor motor is much less than in the wound-rotor motor. Comparisons between measurements and calculations show that most existing theories inaccurately predict the magnitude of transient unbalanced magnetic pull during starting, the effect of slotting and saturation, the effect of a cage rotor, and the action of load currents. A simple theory is developed which gives reasonable agreement with measurements for the wound-rotor motor over a range of supply voltages about the rated value.read more
Citations
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Journal ArticleDOI
Vibration and current monitoring for detecting airgap eccentricity in large induction motors
TL;DR: In this paper, a study carried out to detect air gap eccentricity in large 3-phase induction motors was carried out and the philosophy of using a unified online monitoring strategy was presented and the reasons for selecting line current and frame vibration as the monitored parameters are discussed.
Proceedings ArticleDOI
Analysis of airgap flux, current and vibration signals as a function of the combination of static and dynamic airgap eccentricity in 3-phase induction motors
TL;DR: In this article, a new theoretical analysis of the interaction between harmonic field components due to static and dynamic rotor eccentricity is presented, and the resultant nonsupply-frequency current components produced in the supply current which are highlighted by the analysis are found to exist experimentally and indeed shown to be a function of the combined effect of both dynamic and static eccentricity.
Journal ArticleDOI
Detection of Rotor Slot and Other Eccentricity-Related Harmonics in a Three-Phase Induction Motor with Different Rotor Cages
TL;DR: In this article, the authors used coupled magnetic circuit simulation results for a four pole, three phase induction motor with 44, 43, and 42 rotor slots under healthy, static, dynamic and mixed eccentricity conditions.
Journal ArticleDOI
Calculation and measurement of unbalanced magnetic pull in cage induction motors with eccentric rotors. I. Analytical model
A.C. Smith,D.G. Dorrell +1 more
TL;DR: In this paper, an analytical model for cage induction motors with a static eccentric rotor is described, based on an airgap permeance approach including stator and rotor MMF harmonics.
Journal ArticleDOI
Sources and Characteristics of Unbalanced Magnetic Pull in Three-Phase Cage Induction Motors With Axial-Varying Rotor Eccentricity
TL;DR: In this paper, a model for assessing unbalanced magnetic pull (UMP) due to rotor eccentricity in cage induction motors that takes into account the axial variation in the eccentricity was proposed.
References
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Journal ArticleDOI
Magnetic Pull in Electric Machines
TL;DR: A pole face area in square centimeters is defined as the area of a pole face in square meters as mentioned in this paper.The list of symbols in this article is presented in Section 2.1.
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