Suggestion to electricpete (Electrical) Jul 8, 2002 marked ///\\Here's a list, with the most useful in each category (on-line/off-line) near the beginning of list (my opinion).
On-line:
Vibration analysis
Lube oil monitoring
current signature analysis to check for rotor problems ///The current signature would be more suitable to apply during transition from off-line to on-line.\\monitoring of winding rtd's and bearing thermocouples if so equipped
current magnitude and speed as indicator of loading
(particularly if temperatures are not monitored)
///Also, the motor terminal voltage for undervoltages and overvoltages, sags, swells, spikes, etc.\\infra-red and contact temperature measurements
power analysis for imbalance, harmonics, etc (pdma)
partial discharge monitoring (usually only 13.2kv and above)
ozone sniffer (Draeger tube)
///Acoustic monitoring.\\
Off-line
regrease bearings and change oil using time-based or condition-based strategy
insulation resistance
hi-pot (controversial)
winding resistance test
visual inspection
surge comparison test
///Painting, maintenance, etc.\\