Comparison of EMI signatures to improve condition assessment of generator stator insulation

An important benefit of EMI (Electromagnetic Interference) Diagnostics when applied to identical generators is that the EMI Signatures can be directly compared to better assess the overall health of these machines. This capability allows an accurate ranking of any generator deterioration that may be present and in turn provides critical information to help optimize maintenance practices. Trending data is discussed. Examples of two load tests on several generators are presented. This technique detects loose components. The examples shown include machines with loose windings and tight windings. Comparison of the EMI signatures between similar generators is provided with explanation. Only the verified results of field tests on operating generators are presented.