Dr. Greg Stone was one of the developers of on-line partial discharge test methods to evaluate the condition of the high voltage insulation in stator windings. From 1975 to 1990 he was a Dielectrics Engineer with Ontario Hydro, a large Canadian power generation company. From 1990 to 2021 he was employed at Iris Power L.P. in Toronto Canada, a motor and generator condition monitoring company he helped to form. He is now with Stone Dielectrics. He has published two books on motor and generator winding maintenance, a book on practical partial discharge measurement and authored >200 papers concerned with rotating machine windings. Since 1980 he has also been active in creating and updating many IEEE and IEC standards. Greg Stone has a PhD in Electrical Engineering, is a Fellow of the IEEE and a past-president of the IEEE Dielectrics and Electrical Insulation Society.
Dr. Greg Stone
Keynote Title: Challenges in Monitoring the Insulation Condition of Windings Supplied by Voltage Source Invertors
Abstract: When voltage source invertors (VSI) using IGBTs were first introduced in the late 1980s to control industrial motor speed, even low voltage motors were found to fail due to partial discharges (PD). This led to improved insulation systems for random wound motors rated <1000 V, and the development of PD sensors and instruments capable of measuring PD during the short switching impulses such drives create. Since then, VSI’s have been applied to machines up to several hundred MW, and wide bandgap switching devices have been developed which create voltage impulses of 20 ns and less. These developments have made assessing the insulation condition before winding failure even more difficult. This paper will describe the progress that has been made in applying off-line and on-line PD measurement to such applications, and the prospect for inexpensive, reliable winding continuous monitoring for applications such as electric vehicle and aircraft motors.
Nu’man Fawzal is currently the Operation Manager of AF Conditioning Monitoring Sdn. Bhd. (AFCM), Malaysia, and holds a Category IV Certified Vibration Specialist from Mobius Institute, Australia. Nu’man first started his career in Condition-Based Maintenance (CBM) as Junior Technician in 2003 before continuing his study at Universiti Teknologi Mara (UiTM) in 2006 and a Master’s Degree at Swansea University, United Kingdom (2009). Since 2010, he has been working with AFCM as Certified Vibration Specialist and the Team Leader in Machinery Condition Monitoring. On daily basis, he applied numerous machine diagnostic methods such as time-waveform analysis, phase analysis, Operational Deflection Shape (ODS), Experimental Modal Analysis (EMA), and Advance Turbomachinery Analysis. In 2014, Nu’man took the role of Head of Mechanical Department and lead a group of engineers in performing troubleshooting on-site on incipient or re-occurring failure machine covers offshore/onshore. One of his biggest achievements was successfully leading the CBM program for PETRONAS oil and gas platforms and terminal plants (Sabah cluster) for 3 years. Apart from managing the operation of the mechanical department, he also delivers CBM courses and trains analysts for CAT. I-III Vibration Certification and Ultrasound Category I with examinations through Mobius Institute Board of Certification (MIBOC). So far, he has trained more than 200 students.
AF Condition Monitoring (M) Sdn Bhd
Kuala Lumpur, Malaysia
Keynote Title: Faulty trends, common misdiagnosis and tough troubleshooting cases on an electric machine using vibration analysis
Abstract: The advantage of robustness, compactness, ease of maintenance, and high-power generation make the electric machine the prime mover for most industrial rotating machinery. In order toextend this machine’s life, several maintenance techniques have been applied. This includes the Condition-Based Maintenance (CBM) technique which monitors the machine's performance and identifies any faulty symptoms without the machine’s operational intervention. Combining with other classical maintenance philosophies such as corrective, preventing, and risk-based maintenance), CBM improves machine reliability, lowers the likelihood of serious faults, decreases maintenance expenses, and possibly lessens the chances of operational disruption. In this session, we will share our experience in performing CBM specifically utilizing vibration analysis throughout various industries such as power generation, paper mill, marine, oil and gas on its faulty trends, common misdiagnosis cases, and also cases that is tough to troubleshoot using the current approach. We wish that other CBM practitioners and academicians can aware of these industrial scenarios and help in marching the advancement of this machine diagnostic technology.