Faulty bearings are taken as red

A simple device developed by SKF gives an instant visual warning of an overheating bearing. The TempGuard TMTM sensor is fixed to the bearing. If the bearing overheats, a patch in the sensor changes colour, allowing action to be taken to avoid a failure.

The device is based on a metallic "memory" spring which changes shape as it heats up. There are three versions, each covering a ten-degree span - 50-60°C, 60-70°C and 70-80°C. The device starts to show red when the lower temperature is reached and is fully red by the time the higher temperature is reached. If the temperature drops, the sensor returns to its default "OK" colour.

Bearing temperatures can be affected by a variety of factors including wear and lubrication levels. If the normal operating temperature is exceeded, the lubricant can start to break down, the metallurgical structure of the bearing material can change, and if no action is taken, the bearing can be damaged beyond repair.