Assessment Test


1. What is the most common type of spark igniter used on a GTE?


2. The lubrication principal used by the Kingsbury thrust bearing is _________.


3. The main thrust bearing directly positions which part(s) of the main reduction gear?


4. The purpose of the main reduction gear in a marine gas turbine propulsion installation is to _________.


5. On some marine gas turbine reduction gear arrangements, the reduction gear lube-oil supply pump may also supply oil to which of the following components?


6. What type of main reduction gear arrangement prevents independent axial and rotational movement of the pinions?


7. The main reduction gear performs which of the following functions?


8. What feature is commonly used on articulated reduction gear arrangements for the correction of misalignment between the 1st reduction gear and the 2nd reduction pinions?


9. The term "lockout" on the Synchro-Self-Shifting (SSS) clutch system means that the _________.


10. Rotation of the Controllable Pitch Propeller (CPP) blades is achieved through axial movement of what component in the hub body assembly?


11. What is the purpose of the CPP hydraulic oil power system?


12. On most marine gas turbines used aboard ships, vibration sensors are identified as ______________.


13. In a GTE propulsion installation, the typical control system is designed to perform which of the following three functions?


14. To gain access to a nut or bolt in an area that is hard to reach, you should use what type of wrench?


15. With the exception of having a slot cut in the wrench head, a flare nut wrench is similar to what other wrench?


16. Wrenches that are recommended for use on GTEs should be plated with which of the following elements?


17. When you are using a stroboscope, if the flash speed is faster than the rpm of the object being tested, what effect will this appear to have on the object?


18. Which of the following instruments is designed to help you when performing an internal inspection of the GTE?


19. What type of pliers are designed to reduce the time used in twisting wire on nuts and bolts?


20. Cadmium plated tools should NOT be used when performing maintenance on gas turbines because cadmium particles may become imbedded and cause embrittlement in materials made of _________.


21. Inspection mirrors are commonly used for which of the following purposes?


22. On a propulsion marine gas turbine, if full power temperatures become excessive, what action should the operator take?


23. While standing watch on a ship in the engine room with marine gas turbine engines, if after reducing power in response to a high lube oil supply temperature alarm, the temperature continues to increase, your next step should be to __________.


24. On a vessel equipped with marine propulsion gas turbines, the operators initial response to a high vibration alarm should be to _________.


25. The two main types of "compressor" stalls are known as _________.


26. When working with gas turbine synthetic lube oil, which of the following safety measures should always be observed?


27. hat is the purpose of the LM2500 GTE enclosure heater?


28. Where are the CO2 nozzles located in the LM2500 enclosure?


29. What type of combustor is used by the LM2500 GTE?


30. The gas generator section of the LM2500 GTE is composed of all of the following components EXCEPT which one?


31. The struts of the compressor front frame provide passages for all of the following mediums EXCEPT which one?


32. What is the primary purpose of the diffuser and distributor on the LM2500 GTE?


33. Which of the following components prevent(s) objects smaller than 1/4 inch from entering the engine?


34. How is the HP turbine rotor of the LM2500 GTE cooled?


35. How many stages are in the HP turbine of the LM2500 GTE?


36. The power turbine (PT) of the LM2500 GTE has a total of how many stages?


37. What is the primary function of the main fuel control on the LM2500 GTE?


38. In gas turbine fuel oil system, when the engine fuel oil valves are de-energized, the remaining fuel left in the system is recirculated back to the _________.


39. In order to get a ready indication for a normal start with an LM2500 marine gas turbine, what permissive must be met?


40. The HP turbine 2nd stage blades are cooled by convection, with the cooling air being discharged at the _________.


41. Compared to other types of engines, what is the biggest advantage of a GTE?


42. The term "divergent" is best described as _________.


43. Which of the following terms refers to stator blades?


44. What are the two common forms of blade roots?


45. In the operation of a marine propulsion gas turbine, kinetic and thermal energy required to drive the main propeller shaft are extracted by the _________.


46. Which of the following factors permits a gas turbine to produce 100% power?


47. How do the high-velocity high-temperature gases cause the rotor of a gas turbine to rotate?


48. In a gas turbine, the air charge is permitted to be compressed adiabatically by what factor, process, or condition?


49. An "open cycle" of a gas turbine is best described by which of the following statements?


50. The Brayton Cycle is a series of events best described by which of the following statements?


51. A gas turbine in which exhaust gas heat energy is added to the air charge between the compressor and combustion chamber is classified as a/an?


52. The purpose of the metal spray rub coating on the rotor and stator casing of a marine type gas turbine is to _________.


53. The basic components of a gas turbine gas generator include which of the following?


54. What is the function of the stator in a gas turbine compressor?


55. A pressure stage of a gas turbine compressor consists of which of the following?


56. Before combustion can occur, the combustion air must be delivered to the combustor at a high-pressure and low-velocity. High-velocity, low-pressure air is converted to high-pressure, low- velocity air at what part of the compressor?


57. Why are loose-fitting blades used on the first several stages of large compressors?


58. What is the disadvantage of a dual-entry centrifugal compressor compared to a single- entry centrifugal compressor?


59. Each stage of an axial-compressor of a gas turbine can compress the atmospheric air a total of how many times?


60. What is a midspan platform?


61. Which of the following designs is the most satisfactory method for attaching turbine blades?


62. Turbine disks are commonly attached to the shaft by which of the following methods?


63. What are the two common methods of power turbine blade retention?


64. The turbine nozzle blades convert the combustion gases heat and pressure energy into what form of energy?


65. The turbine nozzles function to direct the gases in what direction?


66. What method is utilized to allow nozzle blades to withstand high inlet temperatures?


67. A centrifugal-flow gas turbine uses what type of combustion chamber?


68. The short length of the can-annular combustion chamber provides for which of the following conditions?


69. Aboard ship, single-shaft gas turbines are used mostly as prime movers for which of the following applications?


70. Which type of GTE can handle a larger volume of air?


71. Which of the following is an advantage of a single-shaft GTE compared to a split-shaft GTE?


72. In a twin-spool turbine, secondary air is most essential for cooling in what section?


73. What type of air seal is used in the sump and turbine areas of a GTE?


74. What type of air seal is used in the combustor and turbine midframe of a GTE?


75. What type of seal is used in the gearbox of a GTE?


76. Ball or roller antifriction bearings are used to support GTE rotors for all EXCEPT which of the following?


77. What is the purpose of the spring in a lip-type oil seal?


78. What type of starter is commonly used on smaller GTEs?


79. Accelerating the compressor to the self sustaining speed of the engine is the function of which of the following components?


80. During a "hung start" of a GTE, which of the following conditions will occur?


81. Petroleum based lubricating oils are NOT suitable for use in GTEs for which of the following reasons?


82. Which of the following components removes the oil from the transfer gearbox?


83. The main lube oil system pump check valves serve to maintain system prime and perform which of the following other functions?


84. The electrostatic vent fog precipitator removes oil mist from which of the following areas?


85. When the main reduction gear lube oil system is secured, which of the following components maintains the air within the casing at less than 35 percent relative humidity?


86. How is the lube oil supplied to each bearing in a GTE controlled?


87. What is the approximate percentage of air extracted from the compressor that is mixed with fuel for combustion in a gas turbine?


88. The fuel oil system of a GTE provides all EXCEPT which of the following?


89. What is the power source for the ignition exciter of a GTE?


90. In the ignition system of a GTE, how is optimum spark achieved?


Total Rating:

click here to go to review now