Modelling of rotor defects in squirrel cage induction motors using the time stepping numerical field analysis

The arrival of cheap and fast microcomputers has stimulated the development of machine condition monitoring systems. Such systems measure one or more machine performance parameters, with a view to detecting the early signs of failure and initiating some form of action. To help developing these systems, a thorough knowledge of the behaviour of the machine in its post-fault condition must be well known and well understood. With this view in mind, a simple, yet reasonably accurate method of analysing the induction machine magnetic circuit under normal and abnormal conditions at moderate cost has been developed. Numerical field analysis is applied to the calculation of induction motors. It is based on a very simple Magnetic Network Technique (MNT) solution of the magnetic field. The field is assumed to be two-dimensional. The three dimensionality of the machine is taken into account within the two dimensional model. The general time-dependence of the field and the motion of the rotor are modelled correctly in a step-by-step solution. The model uses relatively small amount of computation time when compared with the previous methods of analysis. This technique is used for the evaluation of the broken bars effects on the machines performance and magnetic field variation. A series of experimental tests have been carried out. The results obtained are directly compared with the computed ones and they showed a good correlation. Finally, suggestions for suitable methods for the detection of broken bars are given along with some suggestions for future work

Modelling of rotor defects in squirrel cage induction motors using the time stepping numerical field analysis

The arrival of cheap and fast microcomputers has stimulated the development of machine condition monitoring systems. Such systems measure one or more machine performance parameters, with a view to detecting the early signs of failure and initiating some form of action. To help developing these systems, a thorough knowledge of the behaviour of the machine in its post-fault condition must be well known and well understood. With this view in mind, a simple, yet reasonably accurate method of analysing the induction machine magnetic circuit under normal and abnormal conditions at moderate cost has been developed. Numerical field analysis is applied to the calculation of induction motors. It is based on a very simple Magnetic Network Technique (MNT) solution of the magnetic field. The field is assumed to be two-dimensional. The three dimensionality of the machine is taken into account within the two dimensional model. The general time-dependence of the field and the motion of the rotor are modelled correctly in a step-by-step solution. The model uses relatively small amount of computation time when compared with the previous methods of analysis. This technique is used for the evaluation of the broken bars effects on the machines performance and magnetic field variation. A series of experimental tests have been carried out. The results obtained are directly compared with the computed ones and they showed a good correlation. Finally, suggestions for suitable methods for the detection of broken bars are given along with some suggestions for future work

12th International Conference on Vibrations in Rotating Machinery

Since 1976, the Vibrations in Rotating Machinery conferences have successfully brought industry and academia together to advance state-of-the-art research in dynamics of rotating machinery. 12th International Conference on Vibrations in Rotating Machinery contains contributions presented at the 12th edition of the conference, from industrial and academic experts from different countries. The book discusses the challenges in rotor-dynamics, rub, whirl, instability and more. The topics addressed include: - Active, smart vibration control - Rotor balancing, dynamics, and smart rotors - Bearings and seals - Noise vibration and harshness - Active and passive damping - Applications: wind turbines, steam turbines, gas turbines, compressors - Joints and couplings - Challenging performance boundaries of rotating machines - High power density machines - Electrical machines for aerospace - Management of extreme events - Active machines - Electric supercharging - Blades and bladed assemblies (forced response, flutter, mistuning) - Fault detection and condition monitoring - Rub, whirl and instability - Torsional vibration Providing the latest research and useful guidance, 12th International Conference on Vibrations in Rotating Machinery aims at those from industry or academia that are involved in transport, power, process, medical engineering, manufacturing or construction

12th International Conference on Vibrations in Rotating Machinery

Since 1976, the Vibrations in Rotating Machinery conferences have successfully brought industry and academia together to advance state-of-the-art research in dynamics of rotating machinery. 12th International Conference on Vibrations in Rotating Machinery contains contributions presented at the 12th edition of the conference, from industrial and academic experts from different countries. The book discusses the challenges in rotor-dynamics, rub, whirl, instability and more. The topics addressed include: - Active, smart vibration control - Rotor balancing, dynamics, and smart rotors - Bearings and seals - Noise vibration and harshness - Active and passive damping - Applications: wind turbines, steam turbines, gas turbines, compressors - Joints and couplings - Challenging performance boundaries of rotating machines - High power density machines - Electrical machines for aerospace - Management of extreme events - Active machines - Electric supercharging - Blades and bladed assemblies (forced response, flutter, mistuning) - Fault detection and condition monitoring - Rub, whirl and instability - Torsional vibration Providing the latest research and useful guidance, 12th International Conference on Vibrations in Rotating Machinery aims at those from industry or academia that are involved in transport, power, process, medical engineering, manufacturing or construction

Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics

It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations

Bibliography of Lewis Research Center Technical Publications announced in 1991

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific engineering work performed and managed by the Lewis Research Center in 1991. All the publications were announced in the 1991 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses