Table of Contents
What is shaft eccentricity?
An eccentricity is one of the major factors that affect the entire system by causing whirling of the shaft and premature failure of the shaft at high vibration condition. Such high vibration condition can be controlled by an important technique called vibration-monitoring technique.
What is turbine shafting?
THE SHAFT connects the turbine to the generator, turning at the same speed as the turbine.
What is TSI in turbine?
A Turbine Supervisory Instrumentation System (TSI) is a sophisticated, customisable digital computer system used in heavy industry to monitor active turbines for potential flaws, faults, and failures. This console then relays the data to different monitors and terminals in the control room.
What is sagging in steam turbine?
2) Sagging of the rotor happens when the rotor is at ambient temperature and barring is not in place so over time the weight of the rotor which is only supported on the rotor bearings allows the rotor to sag in the middle and again the rotor can come into contact with the stator or casing.
What is eccentricity analysis?
Eccentricity is defined as the offset between the axis of rotation and the axis of symmetry. Eccentricity can take place in different types of mechanical elements, such as pulleys, gears and in any relative positioning between two concentric pieces, as for example the rotor and the stator of an electric motor.
What is the function of turbine shaft?
A turbine is a steam-powered machine that causes a shaft—a rotating rod that transmits power or motion from the turbine—to produce electricity through movement.
What are turbine shafts made of?
Turbine rotor shafts are commonly made of steel grades 25Cr1Mo1VA, 30CrNi3Mo1VA, 26CrNi3Mo2VA, 23CrMoNiWV88 and X750. Turbine shafts are mainly machined through turning and groove-cutting operations with some amounts of drilling. Large amounts of metal are removed and demanding grooves have to be cut.
What is differential expansion in steam turbine?
Differential Expansion on a turbine is the relative measurement of the rotor’s axial thermal growth with respect to the case. Due to the mass of this case, it will expand and contract at a slower rate than the relatively thin (hollow) rotor.
What is eccentricity of a turbine rotor shaft?
Eccentricity of a turbine rotor shaft occurs when the rotor becomes bent, or “bowed” such that its surface exhibits runout, as detectable by a proximity probe or a dial indicator. Eccentricity is an issue for at least 2 reasons, i.e.:
How do you measure the eccentricity of a turbine?
Eccentricity is measured while the turbine is on slow roll (1 to 240 RPM below the speed at which the rotor becomes dynamic and rises in the bearing on the oil wedge) and requires special circuitry to detect the peak- to-peak motion of the shaft.
What is shaft eccentricity and why is it important?
Shaft Eccentricity plays a very important role as part of a Turbine Supervisory Instrumentation (TSI) System on large steam turbines and should be included in retro-fit plans when at all possible.
What causes a turbine shaft to wobble?
Everything is elastic to some extent. The result of this is that the turbine shaft will drift to and from being concentric. The extent to which it does this is called the ECCENTRICITY and it is what causes the “wobble” in any shaft. As trivial as this sounds, it is precisely the opposite.