The paper discusses several fatal failures on the Turning Gear Motor (TGM) over the short time period of one-month, resulting in two motor replacements. The Turning Gear Motor was monitored by an online monitoring system using improved Motor Current Signature Analysis (MCSA), aka. Model-Based Voltage and Current (MBVI). TGM mechanical and electrical malfunctions are reflected in the dynamic current spectrum using improved MCSA. Utilizing this methodology, prompt and precise diagnostics was carried out and subsequent decision could take place regarding the electrical and mechanical integrity of this motor installed on this critical Centreline Machine Train. The paper further shows the real case data analysis and findings on this Electric Motor.