NDLI: Rotor shape vs. rotor field pole shorted turns: Impact on rotor induced vibrations on hydrogenerators

Content Provider	IEEE Xplore Digital Library
Author	Tetreault, A.
Copyright Year	2012
Description	Author affiliation: Tests & Diagnostics Division, VibroSystM Inc., Longueuil, Qc, Canada (Tetreault, A.)
Abstract	In the past few years, quite a few cases have arisen where shorted turns were detected or suspected on a pole of a hydrogenerator. In many instances, the shorted turns are suspected because of sudden excessive vibrations near the rotor, which are observed when the magnetic field suddenly appears in the air gap. In other instances, scheduled tests during outages, such as voltage drop tests, are performed and results indicate shorted turns on one or many poles. Many engineers believe that the presence of shorted turns on hydrogenerators cause excessive vibrations because the shorted turns create a weaker magnetic field at a specific pole when compared to the other poles. Therefore; it is believed that a corresponding vibration at the shaft is induced; which shows up at the upper guide bearing and/or at the combined guide bearing below the rotor. This paper will show that this is not the case, unless the conditions are quite severe, as in a case with an extremely high number of shorted turns, located on many specifically located poles. We will discuss the causes of vibration emanating from the rotor, from the perspective of rotor magnetic flux as well as rotor mechanical anomalies. We will compare the principle of vibrations induced on non-salient 2-pole machines vs machines with large numbers of salient poles, explaining the confusion between the two concepts and why many believe the same issue exists on hydrogenerators. Finally, we will explain why rotor shape is a greater contributing factor to rotor induced vibrations than actual rotor shorted turns.
Starting Page	133
Ending Page	136
File Size	1289714
Page Count	4
File Format	PDF
ISBN	9781467310192
e-ISBN	9781467310208
DOI	10.1109/CMD.2012.6416393
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2012-09-23
Publisher Place	Indonesia
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Vibrations Shafts shorted turns rotor shape Magnetic flux Shape induced vibrations Rotors hydro-generators Generators Magnetic fields
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in