Power Engineering 4B Exam Question Bank, Complete With 2000 Questions And Correct Answers, Latest

Power Engineering 4B Exam Question Bank, Complete With 2000 Questions And Correct Answers, Latest The steam engine will have the steam supply to the cylinder shut off once the piston has travelled: 25 to 35% of its stroke. A prime mover is: Steam turbine. Best Small A single device which converts enough will source of energy into mechanical motion is a/an: A prime mover. Advantages of a steam engine include: It is possible to change the direction of rotation without the use of gearing. They are simple and rugged. They have a slow rotational speed without the need for reduction gearing. A routine daily maintenance operating steam engine should cover first and foremost. The lubricators. One of the first ways to detect the fault in a reciprocating engine is: By sound. Thinking of the steam engine and it's construction, what does eccentric mean? Out of center. A steam engine piston: Has greater driving force on it at the beginning of it stroke. Large power production plants tend to be of the thermal type because they can burn solid fuel and: The heat cycle they use is the most efficient. On a steam engine, what is the purpose of a flywheel? It dampens speed fluctuations. It carries the engine over dead center. What is the main advantage of using the expensive properties of steam? Economy. A gasoline engine is a heat engine. What is its working fluid? Combustion gases and air mixture. What is the purpose of a turbine thrust bearing? To transfer turbine thrust to the load. Shaft sealing carbon glands are: Self lubricating In a turbine with a pressure lubrication system, The high-pressure oil generally goes to the governor system. Where is the low-pressure oil led? To the bearings. What holds a turbines carbon packing rings axially? Spring pressure. Steam pressure. For what purpose is lubricating oil required on a turbine, beside lubrication? To carry heat away from the bearings. In an impulse turbine: The steam pressure is reduced in the nozzles. Reaction turbines: Have a pressure dropped through the moving and stationary blades. Blades or Buckets form the rotor flow passages in the impulse turbines. A steam turbine should trip or shut down when normal operating speed is exceeded by: 10 to 15%. The handwheel used to adjust the turbine speed on the governor is known as the. Speeder. How many basic types of turbines are there? Two. A large reaction turbine will have: Steam pressure dropping through moving and stationary sections Impulse turbines: Have no pressure drop through the moving blades. What do the stationary nozzles of an impulse turbine convert the thermal energy of the steam into? Kinetic energy. The steam turbines exhaust can often supply the process with steam because: It is free of oil. When the steam pressure drop occurs in only the stationary members or components of a turbine, the turbine is known as: An impulse unit. Most turbine overspeed trips operate by: Centrifugal force. A large reaction turbine will have: Steam pressure dropping through moving and stationary section Starting from the boiler and simple power generation cycle, numbering the following components in the order in which the steam/water flows through the cycle. One - boiler feed pump Two - condenser Three- turbine Four - condensate pump Five- feed water heater The great majority of turbine governors are of the Mechanical centrifugal type Turbine overspeed trip: Will close the steam stop valve to the turbine Turbine lubricating oil : Can be used to operate the turbine governor The turbine overspeed trip: Prevents the turbine exceeding the maximum rated speed. Will close the steam stop valve. What is the purpose of the nozzles in the turbine? To increase steam velocities In the turbine with the pressure lubrication system, the high-pressure oil generally goes to the governor system. Where is the low pressure oil led? To the bearings. The overspeed trip of a steam turbine: Is installed on all turbines. The purpose of the turbine glands is to prevent: Steam escaping from the turbine. What is the purpose of a turbine thrust bearing? To transfer turbine thrust to the load. When warming up a turbine: Warm-up is done slowly. The turbine is slowly rotated. The warm-up must be done so that warping is prevented. What are some advantages of the pressure system on the turbine? Minimal maintenance required. Reliable service. Long bearing life. The shrouding installed on the blading of the steam turbine serves to: Confine the steam to the blades. When preparing a turbine for starts, why is it warmed up slowley? To prevent warping. What gives wood its strength? Cellulose. Natural draft cooling towers operate most effectively in large open spaces and: Where wind is relatively constant. Water contained in the airstream at the discharge of the cooling tower is removed: With drift eliminators. Induced draft crossflow cooling tower. In cooling towers, protective films and sacrificial metals are two methods of protecting against what? Corrosion. What is the purpose of the cooling tower? To reduce the temperature of cooling water For water temperatures up to 70°, increase of temperatures of 15 to 30° cause corrosion rates and cooling towers: To double. Micro organisms require carbon to develop. Where would they get this carbon from in the cooling tower? From the cellulose in the wood. Which of the following methods could be used to circulate air in a cooling tower? Induced draft fans. Natural draft. Convection currents. What could happen if the initial treatment of film forming chemicals, in the cooling tower, is to weak? Severe corrosion in unprotected areas is possible. The average amount of water volume, which evaporates from a cooling tower is: 5%. What is steel corrosion in cooling towers mainly due to? Dissolved oxygen. Delignification in a cooling towers wood is the result of: Chemicals such as chlorine. What are advantages of Venturi towers? No fan is required. It is quiet. No fill is required. Reduced maintenance requirements. At about this water temperature, corrosion rates in cooling towers are relatively unaffected. 70°C. What are the two classifications of mechanical draft cooling towers? Forced draft. Induced draft. What makes cooling tower such a good environment for biological growth? An oxygen-rich atmosphere. Warm water. In cold climates, ice formation in a cooling tower may be dealt with by: Slowing the fans down. Reversing the fans. Compared to a crossflow tower, a counterflow tower: Occupies less floorspace. What are splash bars and different chemical methods used to protect the cooling tower against? Biological fouling. How many general methods are there to circulate air in the cooling tower? There are four. Excessive water drift in the cooling tower could be the result of a drift eliminators being out of place or: The water flow rate is too high. How are microbiological organisms most effectively killed in the cooling tower water system? By temporarily raising the concentration of the chemicals to a high-level. Chemical methods used to prevent biological fouling in cooling towers include: Oxidizing chemicals. Non-oxidizing chemicals. Heavy metals. How many subclasses of mechanical drafting cooling towers are there? There are two. In a Venturi type cooling tower, how is airflow created? By spray nozzles. Compared to a crossflow tower, a counterflow tower: Occupies less floorspace. What purpose do both water softener and the addition of sulphuric acid to cooling tower water service? They treat scaling. Approximately how much of a gas turbines power is used to drive it's compressor? 2/3 Dirty air filters on a gas turbine could lead to what alarm? High differential pressure, air intake. The operating power of the gas turbine is directly related to the: Mass of gas passing through the turbine per second. The low installation cost of the gas turbine is: Because less auxiliary equipment is needed. The purpose of a regenerator is: To improve the efficiency of the turbine. What affect would a reduction in air density have on a gas turbine? Power output would be reduced. If a gas turbine operates on natural gas, what may be required? Gas compressor. What fire extinguisher in media are fitted in gas turbine automatic firefighting systems? Halon. Carbon dioxide A gas turbine compressor is usually: An axial design. Many typical steam plant auxiliaries are limited with a gas turbine due to its: Simplicity. The majority of gas turbines are of what style? Single shaft. Simple. Open cycle. The gas turbine is not self starting. It must be rotated at 20% to 30% of its maximum speed before fuel is turned on. Gas turbines are very popular where: Water is scarce. Put the following gas turbine starting operations in the correct sequence. Cranking. Purging. Firing. Acceleration. Early gas turbines were handicapped by: Metals not standing the high temperatures involved. A gas turbine performs most effectively if: Ambient air temperature is low. Which of the following are disadvantages of gas turbines? Noise. Low thermal efficiency. What type of lubrication pump is most commonly used in gas turbines? A gear lubrication pump. What is injected into the air intake of the gas turbine to clean the blades? A detergent. The compressor of a gas turbine: Can be driven by the turbine. Regarding a combined steam - gas turbine plant, which of the following may apply? The gas turbine may exhaust to the boiler. The air compressor may deliver air to the boiler. The boiler may deliver hot gases to the gas turbine. The combustion chamber of a basic gas turbine: Burns fuel with compressed air. Re-generator location fitted on the gas turbine. B What is a diesel engines camshaft? The crankshaft. Reduction in sealing qualities between the piston rings in cylinder wall by the lubricating oil may be the result of High cooling water temperature. If a diesel engines intake or exhaust valves are leaking, which of the following? Insufficient combustion air How high the compression ratio in the diesel engines be? 25 to 1. How many ports does a simple two-stroke spark ignition engine have? Three. Although many new two-stroke spark ignition engines have oil injection, what method of lubrication is still widely used? A pre-mixed oil/gasoline mixture How might the frame of the diesel engine be constructed? Cast. Welded. And injection nozzle is used to Atomize the fuel in a diesel engine. The two cycle gasoline engine: Is of a more simple construction than a four cycle. A four stroke engine which gives high torque at low speeds would be that of a: Four stroke motocross motorcycle. Which develops one power stroke with every other turn of the crankshaft is the: Four stroke natural gas engines. Internal combustion engines used to drive gas compression machines, which burn natural gas to operate use a: Two or four stroke cycle. Natural gas Gasoline Light oil fuel Heavy oil fuel Natural gas - environmentally friendly. Gasoline - may use carburetion Light oil fuel-May use a vaporizer Heavy oil fuel - used in high compression engine. What is a fuels resistance to premature detonation called? Octane rating. Cylinder scavenging Is the removal of exhaust gases from the cylinder What is the purpose of a pushrod in a typical four stroke diesel engine? To operate the rocker arm. Ignition in a diesel engine is started by: Compression in the cylinder. Diesel engine governing is accomplished by Varying the fuel quantity. What problems could be leaking fuel injector cause in a diesel engine? Abnormally high exhaust temperatures Smoky exhaust. How is fuel vaporized in a gasoline engine? An injector. A carburetor. The injection pump of a diesel engine driven by: The camshaft Statement about four cycle engines The exhaust valve opens near the end of the power stroke. To what approximate pressure does the compression in a four stroke diesel engine rise to? kPa Using a compressed air starting motor is the popular method of starting a: Large stationary diesel engine. Rotary pumps: Have tight clearances on all moving parts. Deliver high pressure liquid without pulsations. Are positive displacement units. Should not be started with discharge closed. A pump which supplies oil to the burner is the Fuel oil pump. The sum of static and dynamic head is called: Total head. The capacity of a centrifuge should only be reduced by: Closing in the discharge valve. A double - acting pump : Is a positive displacement pump. The difference between static suction head and static discharge head is: Total static head. A multistage pump would be used: When the head is great A pump capable of producing water pressures above the boiler pressure in order to add water in the boiler is the Feedwater pump Pumps handling cryogenic materials operate: At extremely low temperatures. The distance from the centreline up to the surface of the water in the discharge tank is called Static discharge head When a reciprocating pump discharge in only one direction, it is termed a: Single acting unit. The capacity of a centrifuge should only be reduced by: Closing in the discharge valve The sum of the friction head, velocity, and pressure head is called Dynamic head A pump which supplies water to the cooling tower is the Circulating water pump The positive displacement standby pump will have: The suction valve open and the discharge valve open The distance from the centreline of the pump to the surface of the water in the discharge tank is called Static discharge head The following is a high-pressure pump? Regenerative A volute type pump Has a progressively expanding spiral casing. To prevent cavitation in a centrifugal pump: Pump should have high suction head. The sum of the friction head, velocity, and pressure head is called Dynamic head The difference between static head and static discharge head is: Total static head. Turbine pumps are best suited for: Low capacity high-pressure service. If the pump is cavitating what can you do to prevent or reduce cavitation? Raise the suction pressure Pumps handling cryogenic materials operate: At extremely low temperatures. A multistage would be used: When the head is great. The static suction head of a pump: Is the difference between the static section head in the static discharge. Turbine pump's: Are high-pressure pumps. Has the liquid gain energy in a number of impulses. When starting up a rotary pump you must be sure that the: Discharge valve is open If pump speed is too high: The driver may be overloaded Flexible couplings are used to correct Misalignments that develop during operation A plugged impeller symptom or result will be: No liquid being delivered A slight leakage is desired between the pump shaft and the packing gland in order to: Lubricate the surfaces. If the packing gland of a centrifugal water pump is leaking too much, you should: Tighten up the gland but permits a slight amount of leakage If the stuffing box is to prevent the ingress of air, it is equipped with: A seal cage. The purpose of shaft sealing on a pump is to Stop fluid from leaking along the shaft of the pump Another name for compression type packing is the Jam type packing Another name for a lantern ring in a pump is: A seal cage Mechanical seals: Are used where leakage is objectionable. Replace stuffing boxes Provide a better seal then packing Pump wear rings are installed on an impeller by set screws, threading or: Shrinking. The liquid to a lantern Ring: Keeps the air out of the pump. The misalignment of shafts connected by a rigid coupling causes Increased power consumption. Severe bending stresses. Excessive wear of the bearing. Vibration and noise Overheating. Most pump failures, damage, or both occurs: During initial start up A pump stuffing box: Stops air leaking into the casing when the pressure is below atmospheric. Decreased leakage out of the casing when the pressure is above atmospheric. A pump can be considered primed when Water flows from the vent. What size of packing should you use, to repack a pump gland having the following dimensions: Stuffing box bore= 8.4 cm Pump shaft diameter=5.8 cm 13 mm. The seal cage on the shaft of a centrifugal pump: Distributes sealing water to the packing. A plugged impeller symptom or result will be: No liquid being delivered If pump speed is too high: The driver may be over loaded. Priming of a centrifugal pump refers to: Filling the pump casing with liquid and removing the air Wear rings are usually constructed of: Bronze or cast iron Proper priming and venting of a pump is important, especially if: A mechanical seal is used. For coupling with hubs or flanges of the same diameter a Straight edge and tapered feeler gauge can be used to check for offset and radial misalignment. Priming a water pump means: Filling the pumps casing and suction line with water If the packing gland of a centrifugal water pump is leaking too much, you should: Tighten up the gland but permits a slight amount of leakage. The main advantage of a pump using a mechanical seal is Is less maintenance If a pump is running and has no discharge pressure, what will you do? Check to see if the suction valve is open This component reduces the clearance of the rotating impeller and the stationary casing. The wearing ring. Another name for compression type packing is the Jam type packing. When aligning a pump, a very accurate method of checking flanges for offsets and axial misalignment which can be used on any flanges is the Dial indicator. To reduce air temperature between stages, we would use: An intercooler. An aftercooler which is equipped with a shut off valve between the aftercooler and the receiver, should also be equipped with an Safety valve. An Air compressor auxiliary which will decrease the power requirement is the: Intercooler A belt driven lubricator is very popular on a: Sliding vane unit In order to minimize corrosion inside the air receiver Is periodically drained of water The determining factor as to which type of compressor to use is The maximum operating pressure required Single stage reciprocating air compressors: Could have two cylinders. A start and stop air compressor control should be set to operate at approximately 100 kPa differential Compressor unloaders: Could keep the suction valve open The compressor which would favour volume overpressure would be the: Centrifugal. A method to control the air compressor, which makes use of an internal combustion engine or steam turbine is the Variable speed control Air compressors may have a number of system protective devices. Another label for those devices is Interlocks. Single stage reciprocating air compressors consist of: One or more cylinders of the same size. Where Pistons move in a cylinder it is necessary for the lubricant to provide Sealing. When an intercooler is used, it should be equipped with a: Thermometer. Safety valve. Pressure gauge. Speed increasing gearing is commonly used on the Driver for what type of air compressors? Screw units. Positive displacement compressors: Could be single stage with three cylinders. Which of the following substances are used as an absorbent air dryer Bauxite. Activated alumina. Silica gel And air compressor, which gives to compression strokes per crankshaft revolution, is: Single cylinder double acting. Compressed air tools tend to be: More expensive than electrical tools. Positive displacement air compressors include: Sliding vane. Rotary screw. Rotary lobe. The constant speed control method for an air compressor is usually driven by a Electric motor In a two-stage air compressor, the second stage is Smaller than the first stage. Dynamic air compressors include Centrifugal. Axial flow Intercoolers: Should have a safety valve. By cooling the air between stages of compression the energy required is reduced by approximately 15% A type of air compressor which draws in a charge of air, traps it, then reduces its volume, and discharges it, is A positive displacement compressor. The kind of grease use for heavily loaded machinery operating at low speeds: Specialty Grease. A semi solid lubricant: Is less likely to drip or splash from bearings. Synthetic turbine oil should: Be fire resistant. The characteristics of a good grease are largely determined by: It's thickening agent or soap. If an oils viscosity changes much with little temperature change then it will have a: Low viscosity index. The viscosity of an oil: Determines the ability of the oil to support a load. The majority of lubricants are made of: Mineral oils. The resistance of a liquid to internal de-formation or sheer is known as. Viscosity. Which of the following has the greatest effect on the viscosity of lubricating oil? Temperature. If operating temperature is low, the preferred lubricant is a: Liquid. Lubrication can be achieved by using: Grease or oil. And can be defined as: Resistance to motion. The lubricant performs a number of functions. Indicate which of the following are the most important: Reduce wear. Reduce friction. Lubricant for an antifriction bearing is: Barium and lithium based grease. Oil additives; Should not affect all other characteristics greatly. A material, which is commonly used as a solid lubricant is: Molybdenum disulfide. Greaese are a mixture of oil and: Soap. If ambient temperature is low, the preferred lubricant is a: Liquid. A semi solid lubricant: Has a high viscosity. Is able to seal out dirt and water from bearings. Cannot be used for high temperature. Which type of grease is the cheapest and most commonly used? Calcium base Which type of oil produces higher fluid friction? A high viscosity oil. Air compressor oil should: Have low-carbon and residue Grease is not a suitable lubricant: If a large amount of cooling is desired The neutralization number of an oil indicates The acidity of an oil. A large journal bearing which is running hotter than normal can be cool by: Loosening the bearing caps. Application of installation forces through the balls of the bearing can cause Improper lubrication. Large journal or sleeve bearings have grooves: In the non-pressure area.