Download ABSA 5th Class Exam Study Set 2025-2026 with Solutions and more Exams Power Plant Engineering in PDF only on Docsity!
ABSA 5th Cla 10 ss Stu0% Veridy fied 2025Set With Complet-2026!! e Solutions
A smoke detector using a short beam carried between the light source and receiver,both mounted in one ceiling-mounted unit, is known as: - ANSWER>>A spot type photo-electric detector In a dry standpipe system, how is the supply valve operated? -remote control, or automatically. ANSWER>>manually, by
In a building of high fire hazard, how many square meters below one sprinkler may beprotected? - ANSWER>>6.
SDS/MSDS are written by the __________________. - ANSWER>>Manufacturer Dropping a gas cylinder could lead the cylinder to _________________. -ANSWER>>become a rocket like projectile
The upper explosive limit of a hydrocarbon is the ________________. -ANSWER>>maximum amount of vapour in a given volume to ignite
An emergency plan should include the ________________.
- number of, and who is, first aid trained
- location and number of first aid kits
- a health and safety program4. on-site emergency team
- rehabilitation services - ANSWER>>1,2,
If a mixture has too much vapour to ignite it is known as a ____________ mixture. -ANSWER>>Rich
The __________ fuse is the only fuse for ratings exceeding 30 amperes. -ANSWER>>Cartridge type
A motor that has an extra winding in the stator to give added torque is called a: -ANSWER>>Split-phase motor
A GFI works on comparing __________ on different sides of the circuit. -ANSWER>>Current
What are some types of bearings in electric motors?
- thrust bearings
- sleeve bearings
- pre-lubricated bearings
- ball bearings
- combined roller and thrust bearings - ANSWER>>2,3, Bearings are the most common point of failure of an electric motor. What type ofbearings may a motor have? - ANSWER>>sleeve, ball
What does the results of a hardness test indicate in welding?of the welded joint ANSWER>>The strength
Welding flash is ______________.IR rays ANSWER>>a burn to the eyeballs from excessive UV or
A weld made from both sides of the joint between two pieces of metal is? -ANSWER>>A double weld
What type of weld defects can a fluorescent penetrant or dye penetrant test detect? -ANSWER>>defects that reach the surface
What must a power engineer ensure before allowing any welding to take place in one ofhis/her vessels?
- the equipment must be isolated
- the equipment should be free from combustible or dangerous gases
- low voltage lighting should be available
- the welder should be tested for the type of weld they will be performing -ANSWER>>1,2,
Personal protective equipment that a person carrying out welding would need to wearincludes:
- welding goggles
- safety shoes
- dark, heavy clothing
- hardhat or skullcap
- flameproof gloves -adequate ANSWER>>2,3,4,5 welding goggles on their own are not
A manufacturer's welding procedure shall ___________________. -qualified under the applicable code ANSWER>>be
What is the purpose of a "penetrameter"? -sensitivity and clarity of a radiograph. ANSWER>>It gives an indication of the
A welder's certificate is usually good for what period of time? - ANSWER>>18 months What does a tensile test tell about a weld? -the minimum ultimate strength. ANSWER>>It tells if the weld specimen has Each pass of a welding rod produces ____________. - ANSWER>>A weld bead In welding a coated electrode _______________. -protects the molten metal from air ANSWER>>stabilizes the arc and
When a softener has sat idle for a period of time, the operator should? -a pre-start rinse. ANSWER>>Do
- The sample has to stay at operating temperature - ANSWER>>1,2, The TDS, total dissolved solids test is carried out with ________. - ANSWER>>a meter A more modern method of ridding a boiler of dissolved solids is: - ANSWER>>continuousblowdown
Which of the following chemical compounds are involved in the "exchange" stage of theregeneration cycle of a softener?
- CaHCO3 (Calcium Bicarbonate)
- MgSO4 (Magnesium Sulphate)3. NaCl (Sodium Chloride)
- Ca SO4 (Calcium Sulphate)
- MgHCO3 (Magnesium Bicarbonate) - ANSWER>>1,2,3,4, If a sample of feedwater is being subjected to a hardness test and hardness is present,it will turn what color? - ANSWER>>Red
Water impurities are counter-acted using:
- chemical methods2. thermal methods
- internal methods
- external methods5. mechanical methods - ANSWER>>1,2,
Pot feeders inject the chemicals in extremely slowly and over a long period of time.(True/False) - ANSWER>>False
The molybdate test can be done using:
- a titration
- a meter
- only a boiler water sample4. a comparator
- only a softener sample - ANSWER>>1,2, When doing maintenance on a softener, the zeolite should be? - ANSWER>>Kept most Written communication is _______. -workplace communication ANSWER>>often the preferred method of
A PFD is ____________________. -(Process flow diagram) ANSWER>>A schematic of the process flow of a plant
Large volumes of water are usually filtered by what means?
- Cartridge filters
- Filter Aid filters
- Settling ponds
- Sand beds - ANSWER>>3, The P&ID shows ______________. - ANSWER>>details of all components in a plant
Which of the following are necessary for complete combustion of a fuel?
- enough air must be supplied
- the temperature of the furnace must be high enough3. there must be enough water in the boiler
- enough time must be allowed for the fuel to burn
- the safety valve must be properly set6. the air and fuel must be thoroughly mixed together - ANSWER>>1,2,4,
How can the draft through a natural draft furnace be increased? -ANSWER>>increasing the temperature of the stack
Steam traps are usually located a) at the highest point of a steam line b) at the highest point of a hot water linec) at the lowest point of a hot water line d) at the lowest point of a steam linee) at the hottest point of a steam line - ANSWER>>D
Welding together DN 50 and smaller pipe is usually done by: -welded method ANSWER>>socket
The methods usually used to connect pipe together are:
- welding
- glands
- screwed fittings
- flanges - ANSWER>>1,3, Ring joint gaskets are a) round in cross-section b) flat c) square in cross-sectiond) oval in cross-section e) hollow - ANSWER>>d A method of backflow prevention which makes use of a separation between the freeflowing discharge of a potable water pipe and an open or non-pressure receiving vessel is called __________ backflow prevention method. - ANSWER>>air gap Problems associated with flush valves (flushometers) include:
- Valve won't flush
- Valve flushes too long
- Valves doesn't flush long enough
- Flush is noisy
- Float frequently requires adjusting - ANSWER>>1,2,3,
Why are the inlet vanes of a centrifugal refrigeration compressor held shut whenstarting the unit? - ANSWER>>it reduces the starting torque
The most widely used refrigerant control, which consists of a bellows or a diaphragmchamber connected to a temperature sensing bulb by means of a small capillary tube is a/an - ANSWER>>thermostatic expansion valve How would you know that you have introduced enough refrigerant to a new system? -ANSWER>>You added the amount recommended by the factory and the bubbles disappeared in the sight glass. If a compressor won't start, yet the motor is operational, what may be the cause? -ANSWER>>Coupling sheared or broke
Compared to a halide torch detector, it will only detect system leaks if the refrigerantcontains chlorine. (T/F) - ANSWER>>True
The part of a mechanical seal, that prevents axial leakage, is: - ANSWER>>O-ring A compressor, that utilizes start/stop capacity control: -an electric motor ANSWER>>must be fitted with
Additives to the oila) should have minimal effect on all other characteristics b) will always have a major effect on the pour point c) should be utilized minimallyd) are not a part of many lube oils e) do not at any time loose their activity once in action use of the oil - ANSWER>>A Compressed air entering the microturbine is compressed in the __________. -ANSWER>>Axial flow compressor
Synchronizing of a standby generator set is usually performed -ANSWER>>automatically
The normal supply pressures of the compressed air used for starting the engine is about_________kPa. - ANSWER>>
What is the usual voltage of a ICE generator set starting system? - ANSWER>>12v One bar of pressure in the SI system is: - ANSWER>>100 kPa The operating element of an automatic sprinkler head may be a heat sensitive bulb or: -ANSWER>>Soldered link
A complete electrical circuit must be ______________________. - ANSWER>>continuous When a welder becomes qualified for a welding procedure they are issued_____________. - ANSWER>>A performance qualification card
The two overall types of weld testing and inspection are? -non-destructive ANSWER>>Destructive and
In welding, what do the results of a hardness test indicate? -the welded joint ANSWER>>the strength of
During the regeneration of a sodium zeolite softener, what happens to the elementalimpuritites that are attached to the zeolite? - ANSWER>>They are exchanged for sodium Conditions which can occur within the boiler are ___________ -corrosion, sludge, foaming ANSWER>>scale,
Combustion of a fuel in a boiler furnace: -of excess air ANSWER>>should be done with a minimum
What is a hydrostatic test? -for strength and leaks. ANSWER>>A way in which pressure vessels can be tested
How often do burner and fan motors which uses standard bearing normally requirelubrication? - ANSWER>>Yearly
On a hot water boiler, the pressure differential between the operating pressure and thesafety relief valve set pressure must be (at a minimum):
- 25% of operating pressure
- 125% of operating pressure
- 69 kPa
- 25% of the safety relief valve set pressure - ANSWER>>3, 4 In hot water boiler operation the maximum operating temperature should never exceed:- ANSWER>>121 degrees celsius
A substance, which will absorb humidity inside a boiler during dry lay up is: -ANSWER>>Activated alumina
When draft is produced by natural means: - ANSWER>>cooler air surrounding the boilerincreases draft
Combustible components of coal are: - ANSWER>>Carbon, hydrogen, Sulphur The following are causes of furnace explosions except
- main fuel valve closed when the burner flame is lost
- insufficient purge
- burners lit from hot refractory
- effects of corrosion
- admission of fuel before ignition source - ANSWER>>3,4, Which grade of oil below is the most popular for domestic and small commercialboilers? - ANSWER>>Grade 2
Inclined manometer as compared to the U manometer is what? -accurate. ANSWER>>More
How can the draft through a natural draft furnace be increased? -the temperature of the stack ANSWER>>Increase
The major function of a gas burner is: - ANSWER>>provision of O2 - fuel contact The minimum distance from furnace to oil storage tank is: - ANSWER>>2 feet
With respect to a burner with 3 fixed capacity nozzles,the secondary and tertiarynozzles are lighted by: - ANSWER>>Primary burner
Ethane is a constituent of natural gas and forms a percent volume of: -ANSWER>>10-20%
An interrupted pilot does what? -extinguishes after the main flame is established. ANSWER>>Lights, completes a trial, and
A very popular packaged boiler gas burner is the: - ANSWER>>Ring burner An intermittent pilot does what? -with it. ANSWER>>Lights the main flame and remains on
Before atomization can occur, heavy oils are heated to approximately _____ degrees C. -ANSWER>>
A fuel storage tank must be located a minimum of ____ away from the furnace -ANSWER>>2 feet
A disadvantage of a refractory burner is: - ANSWER>>High initial cost Maximum static pressure in a fuel oil line is about what? - ANSWER>>35 KPA A gas fired burner is burning fuel and operating properly a) it will have a blue flame with short yellow tips b) the furnace will pulsatec) there will be no turbulence
d) it will have a long bright yellow flame e) the induced draft fan can be shut off - ANSWER>>A In a forced draft system, the furnace pressure is: -pressure ANSWER>>Above atmospheric
Copper and copper alloy piping and tubing is not used in power plants when: -ANSWER>>Temperature is a prime factor.
Pipe is manufactured in two main categories, welded and a) threaded b) soldered c) brazedd) flanged e) seamless - ANSWER>>E Steam traps are installed below the ________________ point in the system. -ANSWER>>lowest
The expansion bend has the advantage over the expansion joint for one of the followingreasons: - ANSWER>>There is little chance of leakage
Piping expansion is controlled by:
- anchoring the pipe at both ends to prevent movement
- installing a corrugated expansion joint in the line
- installing an expansion bend in the line4. securing the pipe at both ends and providing hangers at five metre intervals -
