Power Engineering - 4B7 Practice Exam Questions With Outlined Answers

Power Engineering - 4B7 Practice Exam Questions With Outlined Answers Q.Which of the following comes earliest in the start-up sequence of a steam turbine? a. Manually test the overspeed trip. b. Open the steam inlet valve slightly to start the turbine rolling. c. Reset the overspeed trip. d. Close the casing drain valve and ensure the casing drain steam trap remains in service. - ANSWERS-c. Reset the overspeed trip. Q.A routine inspection of an operating steam engine should start with: a. checking the load on the engine. b. checking the boiler pressure. c. blowing off the steam chest drains. d. making sure the lubricators are feeding properly. - ANSWERS-d. making sure the lubricators are feeding properly. Q.The turbine overspeed trip: a. Alerts the operator of excessive turbine RPM b. Opens the sentinel valve c. Adjusts steam flow to keep the speed at set point d. Prevents the turbine from exceeding the maximum rated speed - ANSWERS-d. Prevents the turbine from exceeding the maximum rated speed Q.A starting device for a gas turbine a. is also called "barring gear" b. keeps rotating the turbine shaft until the turbine is up to full load c. must be an electric motor d. is necessary for all gas turbines - ANSWERS-d. is necessary for all gas turbines Q.In theory, impulse turbines: a. Develop the most torque of all turbines b. Can only use only low-pressure steam c. Have no pressure drop through the moving blades d. Have a velocity drop through the nozzle - ANSWERS-c. Have no pressure drop through the moving blades Q.Which of the following is a prime mover ? a. An electric generator b. A gas turbine c. An air compressor d. A boiler - ANSWERS-b. A gas turbine Q.A simple gas turbine is one without reheaters or: a. Regenerators b. Combustors c. Compressors d. Starting motors - ANSWERS-a. Regenerators Q.Steam turbine governors: a. Are not required on reaction turbines b. Should be checked annually by the boiler inspector c. regulate the speed of the turbine automatically d. prevent the turbine from over speeding - ANSWERS-c. regulate the speed of the turbine automatically Q.The injection pump of a diesel engine is driven by: a. A camshaft b. The governor c. The gudgeon pin d. Piston action - ANSWERS-a. A camshaft Q.Some of the characteristics that make the gas turbine a better choice over other prime movers are: a. Increased power output at higher elevations b. its low fuel consumption c. its ability to rapidly start and carry full load d. its high thermal efficiency e. its low power-to-weight ratio - ANSWERS-c. its ability to rapidly start and carry full load Q.Diesel engine governing is accomplished by: a. modulating the pressure of the atomizing air. b. varying the amount of fuel injected on each power stroke c. varying the amount of air-fuel mixture drawn into the engine when the load changes d. varying the load on the engine - ANSWERS-b. varying the amount of fuel injected on each power stroke Q.Excessive wind velocity in a natural draft cooling tower may cause: a. Over-cooling of the water b. Unstable sump water level c. High drift losses d. Damaged louvres - ANSWERS-c. High drift losses Q.The output power of a gas turbine depends upon a. the difference between inlet air and turbine exhaust temperature b. the drive gear ratio between the turbine and compressor c. the temperature at the turbine inlet in Kelvin d. the mass of hot gas passing through the turbine per unit time - ANSWERS-d. the mass of hot gas passing through the turbine per unit time Q.When _____________ leached away from cooling tower wood, it is less able to resist decay. a. natural extractives are b. cellulose is c. lignin is d. sap is - ANSWERS-a. natural extractives are Q.Large internal combustion engines are cooled with: a. Condensers b. Air cooling fins on the cylinder jackets c. Large fans d. Water jackets - ANSWERS-d. Water jackets Q.A major difficulty encountered with a two-stroke cycle engine is: a. The lack of torque at high speed b. The difficulty in cold weather starting c. The high speeds compared to an equivalent four-stroke engine d. Exhausting the spent gases from the cylinder - ANSWERS-d. Exhausting the spent gases from the cylinder Q.Biological attack on cooling tower wood affects the