With the expanding application of gas turbine engines for stationary and ground vehicle use, more people are exposed to the problem of protecting the engines from excessive temperatures. Most engines today use some system involving thermocouples to measure temperature for manual or automatic control.
Various sensor configurations have been developed and examples of each are available which have been selected based on the following: gas temperature to be sensed, response requirements of the controls, environment surrounding the assembly, and annular depth available for sampling.
Most engines employ more than one thermocouple, and the signals are supplied to an engine mounted harness which provides an electrical average of the signals to the indicator or control. Most harnesses in use are electrically either a common point system or an equal resistance branch system fabricated of protection materials selected for the temperature environment in which they exist and the type of handling and abuse to which they will be subjected.
The engine manufacturer must establish the control requirements for the engine which dictates the location and number of thermocouple and the environmental conditions to which the system will be exposed.
Having determined the basic requirements of the system, the engine manufacturer can make use of the engineering skills, materials, and sources developed primarily for aerospace.