News & Views, Volume 46 | NDE Best Practices for Generator Rotors
By: Paul Zayicek 
Three factors typically drive inspection intervals of generator rotors:
- a timeframe recommended by the insurance carrier or OEM
- an engineering evaluation that supports a different inspection interval due to service operation events or existing rotor damage
- industry best practices
Drivers from the OEM include issues defined in service bulletins or technical information letters that pertain to the entire fleet or some subset of the population. Intervals based on engineering evaluations can be derived from an identified damage mechanism with the rotor or with a critical component. An engineering evaluation can also provide for extended inspection intervals in situations where the generator has no inherent material issues, has a clean inspection record, and sees limited operational stress such as in a base-load unit.
