Description : Which of the following statements is true concerning the cleaning of electrical contacts? A. Compressed air should be used to blow out metallic dust. B. Magnetic brushes should be used to remove ... contact resistance. D. Delicate parts should be cleaned with a brush and an approved safety solvent.
Last Answer : Answer: D
Description : To repair a small electrical motor that has been submerged in saltwater, you should _____________. A. wash it with fresh water and apply an external source of heat B. renew the windings ... electrical parts with a carbon tetrachloride cleaning solvent and then blow dry the motor with compressed air
Last Answer : Answer: A
Description : If a small electric motor has been submerged in saltwater for a short period of time, you should _____________. A. send it ashore for rewinding B. rinse it with warm freshwater and bake it dry ... and bake with internal heat D. clean it with carbon tetrachloride and blow it out with compressed air
Last Answer : Answer: B
Description : Which of the following represents the accepted method of cleaning dust and foreign particles from electrical equipment while limiting damage to electric components? A. Carefully wiping off the components ... the components. D. Using carbon tetrachloride as a cleaning solvent to clean the components.
Last Answer : Answer: C
Description : Controller contacts should be routinely cleaned by ________. A. blowing with compressed air B. filing with a bastard file C. wiping with a clean dry cloth D. dressing with crocus cloth
Description : With the DPI method of inspection after the contact time has elapsed the dye should be removed by: a) Spraying the surface with the remover till all dye has gone then wipe with clean cloth b) Spraying with ... remover d) it doesn't matter how it is done as long as all traces of dye are removed
Last Answer : c) Wipe clean, using a clean cloth soaked in a solvent remover
Description : The 'dielectric constant' is a numerical value indicating the effectiveness of a dielectric material in comparison to that of a standard, which is _______________. A. paper or cloth B. glass or mica C. plastic or Teflon D. dry air or a vacuum
Description : When replacing fuses, always make sure _______________. A. to stand on a rubber mat and use rubber gloves B. to use insulated pliers or screwdriver C. the fuse clips are straight, tight, and in good contact D. to increase the fuse rating 10% to guard against 'nuisance blowing'
Description : Before reassembling any machinery, you should _____________. A. replace all bearings regardless of length of service B. apply a heavy coat of oil to all mating surfaces C. clean any corroded surfaces and file all burrs smooth D. coat all parts with alemite grease
Description : Which of the following statements, concerning the general maintenance of a brushless generator, is correct? A. Paint should be applied to insulating surfaces on an annual basis. B. Alcohol should be used to ... . D. Accessible generator parts should be wiped with a clean dry rag on a periodic basis.
Description : During maintenance of circuit breakers, _______________. A. always smooth roughened contact surfaces with a file B. never pass more than rated breaker current through the overload heater element C. ... wear and misalignment of main contacts D. assume heater elements installed are of correct size
Description : Which of the following procedures should be used to maintain a large electric motor during periods of inactivity? A. A thin layer of air-drying varnish should be applied on the windings. B. ... periodically to remove carbon dust. D. Space heaters should be used to prevent condensation of moisture.
Description : Which of the listed precautions should be taken when cleaning the internals of a motor with compressed air? A. Open the machine on both ends so as to allow the air and dust to escape. B. Be certain that the ... panel. C. Be certain that the air is clean and as dry as possible. D. All of the above.
Description : When troubleshooting a console circuit card suspected of being faulty, the last step would be to _______________. A. check the fuses and voltage levels of all power supplies in the console B. clean dust ... -on types D. substitute a new or repaired spare card and check the operation of the circuit
Description : Which of the following precautions should you take when securing propulsion generators and motors for an extended period of time? A. Disconnect the brush pigtails from their contacts and circulate air ... Lift the brushes from commutator collector rings and circulate cool dry air through the units.
Description : The resistance of electric wire will decrease as its _______________. A. length increases B. cross-sectional area increases C. temperature increases D. percent of metallic purities increases
Description : In general, D.C. propulsion motor brush sparking can be caused by _______________. A. incorrect brush grade, pressure or position B. a concentric commutator C. a dark chocolate colored commutator D. all of the above
Description : In D.C. motor construction, the armature coils' ends are _______________. A. soldered to the commutator bar risers B. imbedded into core slots C. crimped together with brush pigtails D. spliced with the field windings
Description : An important factor in reducing D.C. motor commutator wear is _______________. A. keeping the ambient humidity as low as possible B. ensuring a very low brush current density C. establishing the copper oxide surface film D. all of the above
Description : Copper is often used as an electrical conductor because it _______________. A. has high resistance at low temperatures B. has a highly polished surface C. is able to pass current with little opposition D. holds insulation together well
Description : All of the following items can be used in the maintenance of a D.C. propulsion motor's commutator EXCEPT _______________. A. a canvas wiper B. safety solvent C. abrasive dressing stones D. sandpaper
Description : Unnecessary and frequent applications of varnish to the generator windings to repair defective insulation will result in ____________. A. heavy coatings of varnish interfering with heat dissipation B. ... of the rectifier assembly D. a built-up of varnish without changing generator operation
Description : Routine maintenance of dry-type transformers should include ______________. A. preventing the entrance of water from broken pipe lines steam lines B. keeping protective surfaces and insulating bushings free of ... debris C. periodic testing of insulation resistance with a megger D. all of the above
Description : Which of the following statements concerning the maintenance of solid-silver contacts in relays and auxiliary control circuits is correct? A. When necessary, they should always be dressed with a ... they should be held together with moderate pressure while emery paper is drawn between the contacts.
Description : When primary molars are prepared for stainless steel crowns, should the depth for reduction of the proximal surface be similar to the depth of the buccal and lingual surfaces? A. Yes; reduction ... can be seated E. No, because of lateral constriction, the lingual surface needs greatest reduction
Last Answer : B. No, proximal reduction is greater to allow the crown to pass the contact area
Description : When troubleshooting a console circuit card suspected of being faulty, first check for proper voltages to the card and then _______________. A. test transistors or integrated circuits for gain and ... D. de-energize the card and check the printed circuit traces for continuity with an ohmmeter
Description : Air gap readings should be periodicly taken for electrical generation equipment. The best tool to use to take these measurements is a ___________. A. cloth (non-metalic) tape measure B. dial indicator C. inside micrometer D. tapered, long blade, feeler gage
Description : Compressed air should not be used to clean motor controller equipment because ________________. A. it may force metallic particles into coil insulation B. the surrounding area may need additional cleaning C. the air blast dries out insulation quickly D. a mask and respirator would be required
Description : Why can the fluids used to dry clean clothing remove in grease even when water cannot?
Last Answer : Feel Free to Answer
Description : In most of the vacuum crystalliser, vacuum is generally produced by means of a (A) Suction pump (B) Compressed air jet (C) Steam jet ejector with a barometric condenser (D) None of these
Last Answer : (C) Steam jet ejector with a barometric condenser
Description : Solvent used in the Udex (glycol) extraction process for removal of light aromatics from cracked naphtha is (A) Propane (B) Diethylene glycol (C) Aqueous solution (10% water) of diethylene glycol (D) Methyl ethyl ketone (MEK)
Last Answer : (C) Aqueous solution (10% water) of diethylene glycol
Description : Preheating before welding is done to (A) Make the plate softer (B) Burn oil & grease sticking to plate surfaces (C) Avoid plate distortion (D) Prevent cold cracks
Last Answer : (D) Prevent cold cracks
Description : A cylindrical wire is stretched to increase its length by 10%. Calculate the percentage increase in resistance.
Last Answer : A cylindrical wire is stretched to increase its length by 10%. Calculate the percentage increase in resistance.
Description : The failure of ball bearings used in electric motors can result from _____________. A. failure to clean the bearing before repacking B. failure to maintain proper alignment C. excess lubrication forcing the bearing full of grease and eliminating all areas of expansion D. all of the above
Description : In case of dry spinning of polymers, the polymer solution in a volatile solvent is forced through the spinnerates into a warm air chamber, where the solvent evaporates leaving behind the polymer in the filament ... is used for __________ fibres. (A) Polythene (B) PVC (C) Rayon (D) Polyvinyl acetate
Last Answer : (B) PVC
Description : Routine maintenance of dry-type transformers should include ____________. A. cleaning the windings, if accessible, with a vacuum cleaner or very low pressure air B. measuring and recording the winding ... . making sure that the units are close to bulkheads or corners to protect them from damage
Description : Which one of the following is not the law of dry friction? a.If friction is neglected, the reactions are always normal to the surfaces on contact b.Friction always acts to oppose the relative motion of ... its maximum value d.The force of friction is always normal to the surface e.All of the above
Last Answer : d. The force of friction is always normal to the surface
Description : Pick up wrong statement about friction force for dry surfaces. Friction force is (A) Proportional to normal load between the surfaces (B) Dependent on the materials of contact surface (C) Proportional to velocity of sliding (D) Independent of the area of contact surfaces
Last Answer : (C) Proportional to velocity of sliding
Description : If a magnetic controller contact fails to pick up when the operating coil is energized, one possible cause may be _______________. A. low spring pressure B. low voltage to the coil C. the residual magnetism of the contact faces D. dirty contact faces
Description : How to clean the frying pan of grease and carbon deposits without damaging the coating?
Last Answer : How to clean the frying pan of grease and carbon deposits without damaging the coating? Even with the best housewife, over time, the pan will become covered with particles of burnt food, grease and ... the coating. I hope these simple tips will help you remove grease and deposits from your dishes.
Description : A three-phase electrical system is equipped with ground detecting lamps. If one of the lamp goes dark and the other two burn normally before and after the test switch is operated, this indicates _______________. ... of the three phases D. the voltage to the dark lamp is less than that of the system
Description : The life expectancy of electrical insulation, is approximately halved for an increased operating temperature of _______________. A. 10°C B. 25°C C. 50°C D. 100°C
Description : Basic electrical motor action depends on _______________. A. a conductor rotated within a magnetic field B. a current carrying conductor placed in a magnetic field C. the relative force of the commutator and commutating poles D. the relative force of the armature and interpoles
Description : When electrical cables penetrate watertight bulkheads, _______________. A. they should be grounded on either side of the bulkhead B. they must be bent to a radius of six diameters C. a watertight stuffing tube capable of accepting packing should be employed D. they should be secured by a clamp
Description : The item referred to as a pigtail on a DC motor brush rigging is a/an ______________. A. feather spring B. uninsulated wire C. flexible spring adjuster D. brush holder
Description : On some electrical generating equipment one outboard bearing pedestal is insulated from the bedplate. This should be checked with a millivolt meter and a jumper. With the millivolt meter connectd between ... then removed to take a second reading. This eliminates the insulating effect of the bearing.
Description : Burning of controller contacts, when opening, is prevented by _____________. A. coating the contact surfaces lightly with petroleum jelly B. magnetic blowout coils C. an overvoltage release D. an overcurrent release
Description : The purpose of 'R6' in the winch circuit shown in the illustration is to _______________. EL-0102 A. maintain dry conditions within the winch brake box B. keep the series field current at ... to assist the winch in stopping D. limit the armature current during lowering operation with heavy loads
Description : The shear resistance of a soil is constituted basically of the following component. (A) The frictional resistance to translocation between the individual soil particles at their contact point (B) To the ... (C) Cohesion and adhesion between the surfaces of the soil particles (D) All the above
Last Answer : Answer: Option D
Description : If an alternator is to be inactive for a considerable period of time, which of the following actions should be taken? A. It should be disconnected from the prime mover and raised off its bearing supports ... . D. The windings and collector rings should be protected with a thin coat of grease or oil.