On Line Condition Monitoring Procedures for MV and Strategic motors in Process and Power Plant's

摘要

A large amount of equipment is available for effective condition monitoring furnishing information for inclusion into reliability centered maintenance programs. These tools include mechanical measurements such as; Vibration, Running speed, Component temperature, Airflow, differential cooling air temperatures and noise level measurement, as well as electrical measurements such as Line current, Magnetising current, Stray flux, Induced shaft voltage, Voltage balance and Partial discharge detection. This list of tools is further extended by a range of off line equipment that can be used to effectively diagnose the root cause of potential failure anomalies initially detected by the on line techniques. Some examples of these 'off line' tools include Insulation assessment techniques - Loss Tangent and Partial discharge detectors, Magnetic flux testing, Power flux and El Cid techniques, Insulation resistance, Polarisation Index, Resistance and Interturn qualification etc. Measurement of mechanical alignment, bearing and airgap clearances as well as concentricity of rotating components is similarly fundamental to electrical machine health qualification. Confronted with this vast array of diagnostic equipment the plant engineer requires some guidance as to what, how and when it is appropriate to use the correct specific equipment. A cost-effective approach to implementing an on line procedure for routine condition assessment is offered in this paper. A recommended structured investigative procedure using the tools described above to systematically diagnose and evaluate the root cause of the detected condition, deviation from normal operation, is described. The procedures defined relate to diagnostic steps that can be used by the plant engineer to solve operational anomalies on the motors in his plant and be used for machine and motor health care.