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Mechanical overspeed systems on turbines rely on an equilibrium between the centripetal force of the rotating shaft imparted on a weight attached to the end of a turbine blade. [7] At the specified trip point, this weight makes physical contact with a lever that releases the trip oil header, which directly moves a trip bolt and/or a hydraulic ...
turbine overspeed condition where the turbine accelerates over its design speed, typically by 10%; low vacuum in the secondary cooling loop, or condenser; lubrication failure for any number of reasons; vibrations due to any number of issues; In order to trip the turbine, inlet steam must be removed from the feed.
The modern steam turbine was invented in 1884 by Charles Parsons, whose first model was connected to a dynamo that generated 7.5 kilowatts (10.1 hp) of electricity. [12] The invention of Parsons' steam turbine made cheap and plentiful electricity possible and revolutionized marine transport and naval warfare. [13] Parsons' design was a reaction ...
A governor, or speed limiter or controller, is a device used to measure and regulate the speed of a machine, such as an engine.. A classic example is the centrifugal governor, also known as the Watt or fly-ball governor on a reciprocating steam engine, which uses the effect of inertial force on rotating weights driven by the machine output shaft to regulate its speed by altering the input flow ...
The variation of the steam consumption rate ṁ (kg/h) with the turbine load during throttle governing is linear and is given by the “willan’s line”. [1] The equation for the willan’s line is given by: ṁ=aL+C. Where a is the steam rate in kg/kWh, 'L' is the load on turbine in KW and C is no load steam consumption.
In all turbines the blade velocity is directly proportional to the velocity of the steam passing over the blade. Now, if the entire energy of the steam is extracted in one stage, i.e. if the steam is expanded from the boiler pressure to the condenser pressure in a single stage, then its velocity will be very high.
Campbell Diagram of a steam turbine. Analysis shows that there are well-damped critical speed at lower speed range. Analysis shows that there are well-damped critical speed at lower speed range. Another critical speed at mode 4 is observed at 7810 rpm (130 Hz) in dangerous vicinity of nominal shaft speed, but it has 30% damping - enough to ...
The steam passing through the last stage of turbine has a high velocity and a large moisture content. The liquid particles have lesser velocity than that of vapor particles; hence, the liquid particles obstruct the flow of vapor particles in the last stage of the turbine, and therefore, a part of kinetic energy of the steam is lost.