Steam Turbine Governing Quiz
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Questions and Answers

What is the main function of the governor in a steam turbine?

  • To regulate the speed and power output of the turbine (correct)
  • To generate steam for the turbine
  • To transfer mechanical energy to electrical energy
  • To cool down the turbine during operation
  • How does the governor respond when the turbine load increases?

  • By decreasing the amount of steam admitted to the turbine nozzles
  • By shutting off the steam supply completely
  • By increasing the turbine speed
  • By admitting more steam to the turbine nozzles (correct)
  • What type of system are flyweight governing systems?

  • Purely mechanical or mechanical-hydraulic (correct)
  • Gas-powered system
  • High-pressure steam system
  • Electronic control system
  • How does a purely mechanical governor in a flyweight governing system apply force to the steam governor valve?

    <p>Directly or indirectly, using only mechanical means</p> Signup and view all the answers

    What does the governor sense to regulate the turbine speed?

    <p>Turbine shaft speed</p> Signup and view all the answers

    What happens to the turbine speed when the turbine load increases?

    <p>It decreases</p> Signup and view all the answers

    What is the function of the trip-throttle valve?

    <p>Controlling steam admission to the turbine on startup</p> Signup and view all the answers

    What can happen if a turbine is not protected against rotating at excessive speed?

    <p>Centrifugal forces can tear the blades from the blade wheels</p> Signup and view all the answers

    What is the primary element that senses overspeed in the turbine?

    <p>Unbalanced weight</p> Signup and view all the answers

    What action does the trip pin take if the rotational speed of the turbine shaft increases to trip speed?

    <p>It disengages from the trip valve arm to close the trip valve</p> Signup and view all the answers

    What is the purpose of the flyweight assembly in a mechanical hydraulic governor?

    <p>To vary the hydraulic pressure used to position the governor valve</p> Signup and view all the answers

    How does an increase in turbine speed affect the governor sleeve in the flyweight-operated oil relay governing system?

    <p>It moves the governor sleeve upward</p> Signup and view all the answers

    In the hydraulic turbine governing system, what is the purpose of the hand speed changer?

    <p>To adjust the speed of the turbine</p> Signup and view all the answers

    What effect does lowering the pilot valve have in the flyweight-operated oil relay governing system?

    <p>Allows oil to flow below the relay piston and raises the throttle valve</p> Signup and view all the answers

    What maintains a constant oil pressure downstream of the orifice in the hydraulic turbine governing system?

    <p>The bled oil being replenished at the same rate at which it drains to the oil tank</p> Signup and view all the answers

    Study Notes

    Governor Function in Steam Turbine

    • The main function of the governor is to regulate the turbine speed by controlling the steam flow.

    Governor Response to Load Increase

    • When the turbine load increases, the governor responds by reducing the steam flow to maintain a constant speed.

    Flyweight Governing Systems

    • Flyweight governing systems are mechanical-hydraulic systems.

    Mechanical Governor in Flyweight System

    • A purely mechanical governor in a flyweight governing system applies force to the steam governor valve through a linkage attached to a rotating flyweight, which is connected to the turbine shaft.

    Speed Regulation

    • The governor senses the turbine speed to regulate it.

    Turbine Speed under Load Increase

    • When the turbine load increases, the turbine speed decreases.

    Trip-Throttle Valve Function

    • The trip-throttle valve is a safety device that closes the steam valve to shut down the turbine in case of overspeed.

    Consequences of Excessive Speed

    • If a turbine is not protected against rotating at excessive speed, it can cause mechanical failure, vibration, and even break apart.

    Overspeed Sensing

    • The primary element that senses overspeed in the turbine is the flyweight assembly.

    Trip Pin Action

    • If the rotational speed of the turbine shaft increases to trip speed, the trip pin takes action by releasing the trip-throttle valve to shut down the turbine.

    Flyweight Assembly Purpose

    • The purpose of the flyweight assembly in a mechanical hydraulic governor is to sense the turbine speed and regulate the steam flow.

    Governor Sleeve Response

    • An increase in turbine speed causes the governor sleeve in the flyweight-operated oil relay governing system to move upwards.

    Hand Speed Changer Purpose

    • In the hydraulic turbine governing system, the purpose of the hand speed changer is to manually adjust the turbine speed.

    Pilot Valve Effect

    • Lowering the pilot valve in the flyweight-operated oil relay governing system increases the oil pressure, which in turn increases the steam flow.

    Oil Pressure Regulation

    • A constant oil pressure downstream of the orifice in the hydraulic turbine governing system is maintained by the orifice and the accumulator.

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    Description

    Test your knowledge about the governor, a crucial component of a steam turbine that automatically regulates speed and power output at varying load conditions by controlling steam flow. Learn about how the governor responds to changes in turbine load.

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