Assessment Test

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1. The jacking gear must be engaged as quickly as possible when securing the Main Turbines in order to __________.


2. To prevent damage to the turning gear mechanism, which of the following procedures must be carried out before the turning gear is engaged?


3. When securing a main propulsion turbine equipped with carbon packing glands, the vacuum should always be broken before securing the gland seal steam because


4. In securing the main turbines, steam to the second stage air ejectors should be left on for a short period of time in order to __________.


5. The FIRST step in breaking vacuum on a main turbine unit should be to __________.


6. A common cause of the Babbitt linings cracking in a turbine journal bearing is from ________.


7. Excessive thrust bearing wear in a main propulsion turbine rotor should FIRST become apparent by __________.


8. The original bridge gage reading for a reduction gear bearing was measured as .008 inches. A year later, the bridge gage reading for the same bearing is .010 inches. This indicates __________.


9. The main propulsion turbine can be damaged by __________.


10. An overheated bearing in the main propulsion unit is indicated by __________.


11. Most auxiliary turbines do not require an external source of gland sealing steam because they __________.


12. Turbine throttling losses can best be described as a loss of energy occurring __________.


13. The over speed tripping device installed on an auxiliary turbine is automatically actuated by __________.


14. An excess pressure governor is a special type of control device which would normally be found on a __________.


15. Carbon ring packing segments are secured in a shaft gland assembly of a steam turbine by means of __________.


16. Packing rings installed on auxiliary turbines are generally lubricated by __________.


17. Which type of packing is primarily utilized to control steam leakage from the casing of a modern auxiliary turbine?


18. When fitting new carbon ring packing on a turbine rotor shaft, carefully filing the ends of the segments will ______.


19. To test an automatic low lube oil pressure trip on an idling turbo generator and at the same time prevent the chance of bearing damage, you should __________.


20. The turbine of a turbo-electric drive should be secured by __________.


21. An auxiliary turbine boiler feed pump should normally be stopped by __________.


22. A steam driven 750 KW turbo generator has a rated speed of 1200 RPM. The over speed setting for this unit must not exceed __________.


23. In any governor there is a small range of speed in which no corrective action occurs. This speed range is called the governor dead band and is caused by __________.


24. A constant speed hydraulic governor would more than likely be installed on a __________.


25. Which of the following statements describes how the main propulsion turbine over speed relay initiates closing of the throttle valve?


26. When starting a turbo generator, you must provide lube oil pressure to the governor power piston by means of __________.


27. If two turbo-generators with the same no-load speed settings are operating in parallel, the unit whose governor has the lesser speed droop will __________.


28. A pilot valve and servomotor are utilized in mechanical-hydraulic governing systems on a turbo generator unit in order to __________.


29. A back pressure trip on a ship's service turbo-generator functions to trip the turbine under what circumstance?


30. In excess pressure governor would normally be used on a __________.


31. The constant pressure governor of a turbine-driven feed pump maintains which of the following pressures at a constant value for all capacities?


32. In addition to causing erosion of turbine blades, slugs of water in the steam supply to a turbine driven pump can result in __________.


33. A turbo generator back pressure trip can be actuated as a result of __________.


34. The main throttle valve on a main propulsion turbine admits steam directly into the __________.


35. Which of the following statements concerning the design of balanced throttle valves is correct?


36. Which of the following statements represents the function the nozzle assembly performs in an impulse turbine?


37. The labyrinth packing ring in an interstage diaphragm of an impulse turbine is prevented from rotating by _______.


38. Shrouding on impulse turbine blading is held in place by __________.


39. Tenon peening is a technique employed by turbine manufacturers to __________.


40. Which of the steam losses listed would be associated with a multistage impulse turbine rather than a multistage reaction turbine?


41. The purpose of shroud bands secured to the tips of the turbine blades is to __________.


42. Steam passing through a multistage impulse turbine does not impart any appreciable axial thrust to the rotor. This is primarily due to the __________.


43. In an impulse turbine, the fixed blades function to __________.


44. A pressure-velocity compounded impulse turbine consists of __________.


45. Design characteristics of a velocity-compounded impulse turbine include the utilization of __________.


46. Nozzle diaphragms are installed in pressure-compounded impulse turbines to __________.


47. An impulse-reaction turbine is characterized by which of the following arrangements?


48. In what classification of steam turbines are the moving blades and the adjacent fixed rows of blades shaped to act as nozzles?


49. In which type of turbine does a pressure drop exist through the fixed blades and the moving blades?


50. An energy loss associated with a reaction turbine, but not an impulse turbine, is


51. What is used to compensate for the increased possibility of blade vibration occurring with impulse turbine blading?


52. A pressure drop occurs across both the moving and fixed blades of a reaction turbine as a result of the __________.


53. Which of the parts listed for a reaction turbine serve the same function as the nozzles of an impulse turbine?


54. Why do double flow reaction turbines produce very little axial thrust?


55. What happens to the steam as it moves across the moving blades in a reaction turbine?


56. The general method of reducing turbine reaction blade vibration is by the use of _______.


57. Large temperature and pressure drops which occur in the first stage of a combination impulse and reaction turbine are caused by steam passing through __________.


58. Concerning the classification of steam turbines, a cross compound designed unit


59. In a cross-compounded turbine propulsion plant, steam enters the __________.


60. Why is superheated steam used in the main propulsion turbines instead of saturated steam?


61. What is generally found at the end of the low pressure turbine rotor of a cross-compound turbine arrangement?


62. As steam accomplishes work in an engine or turbine, the pressure of the steam is reduced because it __________.


63. When a turbine is in operation, a rotor position micrometer is used to determine any change in rotor


64. A turbine assembly in which steam flows in series through a high pressure turbine and then on to a low pressure turbine, with both turbines driving a common reduction gear through separate shafts, is classified as _________.


65. As steam first enters the main propulsion turbine, which of the following energy conversions takes place?


66. For a large main propulsion turbine, the most commonly used turbine thrust bearing is the


67. Journal bearings used with modern turbine rotors are manufactured in two halves in order to __________.


68. Which of the journal bearings listed most easily accommodates the minor turbine shaft misalignment?


69. The adjustable spherically seated self-aligning bearing housings used in main turbines are provided with oil deflector rings. The function of these rings is to __________.


70. The correct radial clearances between the rotor and the casing in a propulsion turbine are maintained by the turbine __________.


71. On a main propulsion turbine bearing, the readings obtained with a bridge gage represent the __________.


72. Main steam turbine bearings are lined with __________.


73. For a large main propulsion turbine, the most commonly used turbine thrust bearing is the _


74. An efficient seal is normally obtained between the upper and lower halves of a turbine casing by __________.


75. Turbine casing flanges are sometimes provided with a system of joint grooving to


76. Allowance for axial expansion of the steam turbine due to temperature changes is provided for by the use of __________.


77. Which of the devices listed is found on an LP main propulsion steam turbine casing?


78. The purpose of the sentinel valve installed on a turbine casing is to __________.


79. The astern element of a main propulsion turbine is usually designed as a/an __________.


80. Labyrinth seals used to reduce leakage around a turbine shaft are constructed of __________.


81. When turbine rotor shafts extend through the casing, an external source of sealing steam is used in conjunction with labyrinth packing to __________.


82. The labyrinth seals used on rotating steam turbine shafts reduces external leakage by causing __________.


83. Labyrinth packing rings are installed on turbine diaphragms to minimize __________.


84. Where are moisture shields located in a main propulsion steam turbine?


85. The jacking/turning gear mechanism of a main propulsion geared turbine installation is normally connected through mechanical linkage to the _______.


86. The jacking/turning gear mechanism of a main propulsion geared turbine installation is normally connected through mechanical linkage to the _______.


87. The jacking gear on main propulsion turbines can be used to __________.


88. The main propulsion shaft turning gear usually connects to the free end of the high-speed high pressure pinion because the __________.


89. Which of the devices listed is generally used to engage the main engine turning gear to the high pressure turbine high-speed pinion?


90. The main propulsion turbine should be operated with the __________.


91. Operating a steam turbine propulsion unit at medium speed, in an area with extremely cold seawater and the main circulating pump providing full cooling water flow to the condenser will result in __________.


92. During normal operation of a main propulsion turbine, the lube oil supply temperature to the bearings should be maintained at approximately __________.


93. Before placing the jacking gear in operation on a main turbine unit, you must always insure that __________.


94. The most critical period of main turbine operation is during cold start-up, rather than hot shutdown because __________.


95. Prior to rolling the main turbines in preparation for getting underway, you should


96. Which of the listed procedures should be followed when raising vacuum on the main propulsion plant prior to getting underway?


97. After properly lining up the main propulsion turbine for warm up, steam should first be admitted to the rotor through the ________.


98. When a turbine rotor is not rotating during maneuvering, the heat tends to be concentrated at the __________.


99. With vacuum up and the main propulsion turbine standing by while awaiting engine orders, it is necessary to roll the unit alternately ahead and astern every five minutes to __________.


100. To stop the rotor of a main turbine while underway at sea you should __________.


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