TABLE OF CONTENTS Chapter 2 described the construction and operation of electrical machines and the way they fail in service. We now need to move towards identifying the condition monitoring that needs to be applied to detect those faults.
Condition monitoring has been seen primarily as the province of those who analyse fault signals and interpret results. However, interpretation must be informed by causality and the authors' view is that one of the important changes to occur in condition monitoring over the last 30 years is ensuring that it is firmly directed towards the root causes of machine failure. In so doing, successful condition monitoring directly addresses machine unreliability or, more importantly for the operator, lack of availability. This chapter sets out the issues concerned with this causality.
In considering the progression to failure of machinery it is necessary to define a number of useful terms.
Failure is when the electrical machine fails to perform its energy conversion function. Failure is complete and does not imply partial functionality.
Failure mode is the manner in which final failure occurred. For example
insulation failure to ground,
structural failure of a shaft.
Root cause is the manner in which the failure mode was initiated. For example for the two cases above
overheating of the insulation could be the root cause leading to the failure mode of insulation failure to ground, or
excessive shock torque being applied to the shaft could be the root cause leading to the...
