Transient current analysis for fault detection in large induction motors.

The majority of modern day health monitoring systems for polyphase squirrel cage induction machines, which employ the motors supply current as the diagnostic parameter, require the motor under investigation to be operating under fully loaded, steady state conditions before any useful information may be obtained. The aim of the following research project was to develop a practical and portable monitoring system which would allow diagnostic information of both laboratory, and more importantly, industrially operated motors, to be obtained via information contained within the motors supply current transient. Thus making redundant the constraining operating conditions of previous current monitoring diagnostic systems. Using the induction motors supply current transient, an electrical phenomenon which exists for a finite period of time during the motors initial acceleration, both historical and modern day signal processing techniques were investigated in order to attain their individual suitability for extracting the required diagnostic information. The signal processing techniques employed were further used to investigate the possibility of extracting more information from the current transient, in particular, the location of a rotor fault within the squirrel cage rotor of the motor under investigation. To support this work a three phase Squirrel Cage Induction Motor with inverted geometry was commissioned. This motor allowed simpler monitoring access to the individual rotor bar currents, without the necessity for intrusive search coil mechanisms to be present between the stationary and rotating circuits. In conjunction with these investigations, the laboratory based inverted motor also allowed, due to its inherent design, an investigation into the flow of rotor bar currents to be undertaken, particularly when under faulty rotor conditions. Using the findings from the above work a portable motor health monitoring system was successfully developed. The system, still in a prototype stage, contains both data acquisition and analysis sections and has been proven to give good diagnostic results both in the controlled laboratory and more variable industrial environments.

Grantor dc:publisher.institution

Robert Gordon University

Year dc:date.issued

1996

Author dc:creator

• Burnett, Ronald

Advisor dc:contributor.advisor

• J.F. Watson, W.T. Thomson, D.G. Dorrell and S. Elder

• Health monitoring systems
• Polyphase squirrel cage
• Induction machines
• Transient current
• Diagnostic information

Language dc:language

en

Identifier

oai:rgu-repository.worktribe.com:2807311
https://doi.org/10.48526/rgu-wt-2807311

OAI identifier oai:identifier

oai:rgu-repository.worktribe.com:2807311