Historical Development of MCSA

The following is an excerpt from William T. Thomson’s book:

Current Signature Analysis for Condition Monitoring of Cage Induction Motors: Industrial Application and Case Histories, First Edition
Author(s): William T. Thomson Ian Culbert
First published:17 December 2016

For further reading, the list of references used is attached at the end of the text.

HISTORICAL DEVELOPMENT OF MCSA

In the late 1970s to mid-1980s, novel and fundamental research and development work was simultaneously initiated in the United States, United Kingdom, and mainland Europe on the study of current (and spectra) as a function of cage winding breaks in induction motors. In the United States, this work was reported by, for example, Kliman et al. [1.43, 1.44] and in the United Kingdom and mainland Europe various researchers reported on this topic, including, Williamson, [1.45], Vas [1.46], Deleroi [1.47], Hargis et al. [1.48], Tavner [1.49], Filipetti et al. [1.50], and Thomson [1.34].
In 1982, Thomson initiated research into the diagnosis, via MCSA, of unacceptable levels of operational airgap eccentricity in large HV induction motors operating in power stations and offshore oil production platforms and was the first to report an industrial case history in 1986, when an airgap eccentricity problem was diagnosed [1.37].

With advances in digital signal processing, in the late 1970s, it became possible to produce accurate current spectra of the electrical current to the motor and thus diagnose current signatures indicative of cage winding breaks or abnormal levels of airgap eccentricity between the rotor and stator. Both these problems can lead to consequential stator winding and core damage and failures. Although spectrum analyzers and commercially available MCSA instruments can produce current spectra, which present information pertaining to a cage winding break or abnormal airgap eccentricity and are now widely used by industry, it has to be recognized that such instruments are measurement tools to provide current spectra as the initial source of information to be subsequently interpreted as to whether a problem may or may not exist.

It is important to appreciate that MCSA “cannot distinguish” between broken rotor bars and a broken end ring and it certainly cannot identify the position in the cage winding where there is a broken bar. In practice this is not required by industrial end users, since they are only interested in the operational integrity of cage windings in induction motors and whether there is truly a cage winding break that can lead to a motor failure and downtime. When an MCSA instrument indicates that broken rotor bars exist, it cannot deliver a decision on the action to be taken by the end user and it is here, via the case histories, that this book provides the knowledge to assist end users in decisions on the action to be taken to prevent a catastrophic failure.