Open AccessInfluence of Thermal Expansion on Eccentricity and Critical Speed in Dry Submersible Induction Motors
Author(s) -
Qiang Lv,
Xiaohua Bao,
Yigang He
Publication year - 2014
Publication title -
journal of electrical engineering and technology/journal of electrical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.226
H-Index - 27
eISSN - 2093-7423
pISSN - 1975-0102
DOI - 10.5370/jeet.2014.9.1.106
Subject(s) - eccentricity (behavior) , stator , rotor (electric) , air gap (plumbing) , squirrel cage rotor , vibration , critical speed , induction motor , finite element method , engineering , thermal expansion , thermal , mechanics , structural engineering , mechanical engineering , physics , materials science , electrical engineering , acoustics , meteorology , voltage , political science , law , composite material , thermodynamics
Rotor eccentricity is one of the major factors that directly influence the security of horizontal electrical machines, and the critical speed of the shaft has a close relationship with vibration. This paper deals with the influence of thermal expansion on the rotor eccentricity and critical speed in large dry submersible motors. The dynamic eccentricity (where the rotor is still turning around the stator bore centre but not its own centre) and critical speed of a three-phase squirrel-cage submersible induction motor are calculated via hybrid analytical/finite element method. Then the influence of thermal expansion is investigated by simulation. It is predicted from the study that the thermal expansion of the rotor and stator gives rise to a significant air-gap length decrement and an inconspicuous slower critical speed. The results show that the thermal expansion should be considered as an impact factor when designing the air gap length.