Influence of magnetic fields on turbo-molecular pumps

Ogiwara, Norio; Kanazawa, K.; Inohara, Takashi; Wada, Kenta

doi:10.1016/j.vacuum.2009.06.029

Cited by 10 publications

(2 citation statements)

References 3 publications

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“…Therefore, in the past decade, a wide variety of technical topics on TMP systems were studied such as pumping speed (Giors et al, 2010; Kobayashi et al, 2009; Sengil, 2012; Sengil and Edis, 2011; Shams et al, 2010), influence by external magnetic field (Biswas et al, 2011; Größle et al, 2012; Ogiwara et al, 2009, 2013; Wolf et al, 2011), vibration suppression on TMP blade rotor (Herzog et al, 1996; Liu et al, 2002; Okubo et al, 2013; Nakamura et al, 2014) and so on. As to the vibration suppression on TMP blade rotor equipped with active magnetic bearings (AMBs), a few well-known methods such as automatic balancing system (ABS), peak-of-gain control (PGC) and other approaches were often discussed (Herzog et al, 1996; Liu et al, 2002; Okubo et al, 2013; Nakamura et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Rotor speed control strategy to avoid resonance frequencies of turbo-molecular pump

Chiu

Tsai

2018

Transactions of the Institute of Measurement and Control

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A novel design of composite turbo-molecular pump (CTMP) is proposed. The major configuration of CTMP is composed by a coarse pump, a turbo-molecular pump (TMP) and a magnetic gear unit (MGU) capable of speed amplification. The modal analysis and the study on rotor/bearing dynamics are undertaken at first to estimate the resonance frequencies of the TMP blade rotor itself solely and the interactive dynamics of blade rotor/radial active magnetic bearing (BR/RAMB) subsystem. Secondly, an economical and efficient method by adjusting the angular acceleration speed of BR, namely RDPS, is proposed to ensure the natural frequencies of BR/RAMB sub-system are not driven by the rotor speed all the time. Besides, a speed route of rotor during the take-off cycle of TMP is proposed to satisfy the requirements of system stiffness and prevention of system resonance being driven. Finally, a position conversion method is introduced to solve the problem of distinct locations of gap sensors and the actual gap between rotor and the auxiliary bearings such that the measurement feedback to the controller, RDPS, becomes applicable to formulate the correct actions for providing enough gap margin to prevent collision of rotor against bearings. To sum up, the CTMP possesses the merit of reduction of electrical energy consumption by 17%, compared with the conventional TMP unit. By intensive computer simulations, the RDPS indeed manifests its outstanding performance to efficiently skip or bypass the natural frequencies of the closed-loop system within a very short time period and guarantee the system stability.

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Section: Introductionmentioning

confidence: 99%

Rotor speed control strategy to avoid resonance frequencies of turbo-molecular pump

Chiu

Tsai

2018

Transactions of the Institute of Measurement and Control

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“…Turbo-molecular pumps (TMPs), as an important type of industrial equipment, have been widely used in process, which needs an ultra-clean environment such as chemical vapor deposition, etching processes, and so on [7].Therefore, in order to obtain an ultra-clean vacuum environment, the oilfree AMBs (Active Magnetic Bearings) technology were widely employed in the TMP system [8][9][10]. The object studied in this paper is a radial magnetic bearing(RMB) used in a TMP.…”

Section: Introductionmentioning

confidence: 99%

Influence of Processing Location Hole on a Radial Magnetic Bearing Performance

Ren¹,

Le²

2017

dtetr

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Abstract.As an electromechanical product, the performance of a magnetic bearing (MB) is determined not only by the original design, but also by the process and the assembly process. The location hole is a necessary part of the machining and assembly. In this paper, the influence of the location hole on the performance of the magnetic bearing is analyzed by the combination of equivalent magnetic circuit method and finite element method. The main performance with and without location hole are compared in detail, including magnetic field distribution, bearing capacity, current stiffness and displacement stiffness. Through the analysis, the sufficient margin for installation process should be fully guaranteed at design stage.

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