Thermal instability in a magnetically levitated doubly overhung rotor

Takahashi, Naohiko; Kaneko, Shigehiko

doi:10.1016/j.jsv.2012.09.001

Cited by 9 publications

(4 citation statements)

References 11 publications

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“…For most applications and horizontal rotors, low frequency force capacity is the most important. Based on industrial AMB-rotor systems presented in the literature (and comfortable control lift off and low frequency operation) a nominal overall force capacity of radial AMBs is selected as 5-7 times the gravity force, e.g., 6.24 in [26]. For vertical rotors this force capacity to rotor weight ratio can be lower, e.g., 1.13 in [27].…”

Section: Sensormentioning

confidence: 99%

Design Space Method for Conceptual Design Exploration of High Speed Slitted Solid Induction Motor

Kurvinen

Choudhury

Narsakka

et al. 2021

2021 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

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Design of High Speed (HS) electric machines is an iterative process that requires a multidisciplinary design team to accomplish the required performance. In this study, a design space method (DSM) is developed to streamline conceptual designing of a high-speed and high-power electric machine. The method uses analytical equations and a rotordynamic model to determine geometrical dimensions based on the application requirements. These dimensions create a feasible baseline design for the particular application. However, considering the dimensions as design variables and using the baseline design as a starting point, a multidimensional combination and interaction of the design variables and the correlated output for the particular topology of motor and performance range can be further studied for design exploration and optimization purposes. The study includes a test case where the baseline dimensions are determined and compared to an existing machine from literature, and then further explored to identify the sensitivity of different outputs with respect to different design variables. The method enables rapid design iterations, rotordynamics and rotor mass optimization. The baseline design can be also used as a starting point for the detailed design.

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Section: Sensormentioning

confidence: 99%

Design Space Method for Conceptual Design Exploration of High Speed Slitted Solid Induction Motor

Kurvinen

Choudhury

Narsakka

et al. 2021

2021 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

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“…Equations (34) and (35) constitute systems of two inhomogeneous algebraic for Q 1 (T 2 ), P 1 (T 2 ) and Q 2 (T 2 ), P 2 (T 2 ), respectively. Their homogeneous parts have a nontrivial solution.…”

Section: Primary Resonancesmentioning

confidence: 99%

Nonlinear forced vibrations analysis of overhung rotors with unbalanced disk

2015

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In this paper, primary resonances of a cantilever flexible shaft carrying a rigid disk at its free end (overhung rotor) are investigated. Unbalance forces due to eccentricity and disk skew are simultaneously considered, and the shaft has initially static deflection due to the rotor's weight which causes asymmetry in the equations of motion. The rotor has large amplitude vibrations, which lead to nonlinearities in curvature and inertia. In the model, rotary inertia and gyroscopic effects are included, but shear deformation is neglected. The method of multiple scales is applied to the discretize differential equations of motion. It is shown that the static deflection creates second-order nonlinear terms and near the primary resonances only the forward modes are excited. With considering the gravity, the inertial nonlinearities become stronger near the primary resonances. So, gravity decreases the hardening effect, and the nonlinear system tends to a linear system. It is concluded that the gravity effect has a softening effect. By using this property of gravity, a relation between weight and external forces is derived, in which by applying this relation the jumping phenomenon is eliminated. Numerical examples are presented, and the result is verified by numerical simulations.

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“…Kanemitsu et al attempted to identify mass unbalance and sensor runout (38) . The author's group analyzed the thermal bending vibration occurring in systems supported by magnetic bearings (39) . Well-known similar phenomena are the Newkirk effect caused by contact heat and the Morton effect caused by heat generated from the oil film in lubricated bearings.…”

Section: Rotordynamicsmentioning

confidence: 99%

Reviews of Magnetic Bearing Development in Japan

Takahashi

2013

JSDD

Self Cite

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In the 1980s, active magnetic bearings attracted attention because of their benefits that include contact-free support, no lubrication and low energy consumption, and their industrial applications were extensively studied. In the 1990s, the latest control theories were applied to magnetic bearings, and bearingless drive technologies were established. Magnetic bearings were increasingly applied to industrial machinery and started to find use in artificial hearts. The number of researchers engaged in research on magnetic bearings rapidly increased in Japan, and many achievements were reported. Currently, however, less research is being carried out. In this article, Japan's contribution to the research and development of magnetic bearings is reviewed, particularly key works in the early days of magnetic bearings, from various aspects such as control, rotordynamics, self-sensing, bearingless drives, bearing loss, touchdown bearings, industrial applications, and standardization.

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Thermal instability in a magnetically levitated doubly overhung rotor

Cited by 9 publications

References 11 publications

Design Space Method for Conceptual Design Exploration of High Speed Slitted Solid Induction Motor

Design Space Method for Conceptual Design Exploration of High Speed Slitted Solid Induction Motor

Nonlinear forced vibrations analysis of overhung rotors with unbalanced disk

Reviews of Magnetic Bearing Development in Japan

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