A unique and independent unit condition monitoring technology for rotating machinery, called Shaft Condition Monitoring (SCM) provides early warning of developing problems by monitoring and analyzing shaft voltage and grounding current profiles. The process begins with capturing and trending of critical information inherent in raw signals derived from reliable shaft-riding brushes. Through analysis of this critical information, problems in rotating machinery are detected at their inception or long before they are apparent on traditional instruments. With this data in hand, a proactive plan of monitoring and maintenance is facilitated, possibly averting the extreme costs of failure and forced shutdown.