Here is my scenario, two power plants, one built in two stages, commisioned the first stage in 91' the second stage commisioned in 95'. No documentation on any maintenance of electric motors, have been "fixing it" when it breaks, high turnover rate, obviously someone in the past has done greasing with incorrect grease (lithium added to polyurea and calcium). Many motors tagged out as "bad motor".
Second power plant commissioned in 2001, 18 out of 18 20 HP motors have been rebuilt due to wrong grease added, too much grease added, corrosive atmosphere, standard 256T motor mounted vertically in tropical environment, etc. Developing program in both plants to include PM's on electrical motors, want to go with something that has worked in other plants.
Environment is tropical,i.e., lots of rain, high humidity, mid to high 80's everyday, saltwater corrosive.