You've set up a sound preventive maintenance program. You've even added some predictive maintenance elements to it. Yet, your motors and other rotating equipment continue to suffer from catastrophic failure. Isn't there something to tell you what's going on? Yes: Ferrography.
If you like having a thermography program to protect your power distribution system, you'll love having a ferrography program to protect your motors. Astute plant engineers have a qualified service perform oil analysis on their transformers. If you're familiar with such an analysis, you know you'd never go without it. By looking at the oil, you can determine what kind of preventive maintenance you need to do on your transformers. Ferrography is a similar kind of analysis. In addition to (or, if you choose, instead of) examining the lubricant (oil or grease), you examine the particles in the lubricant. This tells you what problems you need to address. This is an early warning system that can help you win the war against downtime. How best to use it? Schedule ferrographic testing on a regular basis. Schedule more frequently for critical equipment.
Ferrography is a microscopic examination process developed in 1971. Initially, it looked at ferrous wear particles in lubricating oils. Advances in technology now allow ferrographers to classify wear particles from many substances, both magnetic and nonmagnetic. So, although we refer to this as ferrography, we no longer limit it to ferrous metals. The ferroscope (a bichromatic microscope) uses magnifications up to 10002. The ferroscope uses both transmitted and reflected light sources with various filters to distinguish the size, composition, shape, and texture of particles.
The following images (in the original article) show sixteen ferrographic categories. From these images, you can see this is a powerful tool. Each photo shows you a condition, and each caption tells you the cause. Armed with this information, you can shoot down problems before they show up on your normal radar.