This chapter shows that temperature measurement can yield very valuable bulk indications of the condition of an electrical machine using simple sensors and narrow bandwidth (< 1 Hz), low -data-rate signals and, because temperature limits the rating of a machine, over-temperature is a valuable condition-monitoring signal. Temperature detection has repeatedly been shown to be an effective global monitoring technique for electrical machines, but has been neglected as a monitoring method. Temperature measurement is usually done in traditional and rather antiquated ways, and there are some simple changes that could be made in existing practice to make more sense of it. These changes are generally in the area of signal processing and in particular the importance of presenting temperature rises to the operator, rather than absolute temperature. There are also advances in the application of modern sensors, which will allow temperature measurements to be made closer to the active parts of a machine, and these should be exploited.

Inspec keywords: electric machines; temperature sensors; condition monitoring; temperature measurement

Other keywords: electrical machine; temperature measurement; global monitoring technique; coaxial electrical circuits; interference-free measurements; signal processing; temperature monitoring; condition monitoring signal; low -data-rate signals; temperature detection

Subjects: a.c. machines