ABSTRACT
In controlling, monitoring, or analyzing gas turbines the basic objective is to maximize performance, reduce maintenance, and reduce unit downtime. In general, a gas turbine may be viewed as consisting of accessory equipment (controls, lube oil pumps, ignition system, etc.), rotational mechanical equipment (rotor bearings), and thermodynamic gas path elements (gas containment path, compressor, combustor, and turbines). A controlling or monitoring system must pay attention to the three areas of the gas turbine system: The thermodynamic gas path; Vibrations of bearings, rotors, and gearboxes; Lubrication, control, and other accessory subsystems. Vibration measurements usually consist of amplitude (inches), velocity (inches per second) and acceleration (inches per second per second or "g"). Exhaust gas temperature is one of the most critical parameters in a gas turbine, in view of the fact that excessive turbine temperatures result in decreased life or catastrophic failure. Rotor speeds are commonly used as control functions on almost all gas turbines.
