Description : The reactive power drawn by a motor from an AC generator is the power which is _____________. A. used to establish the magnetic field of the motor B. lost in overcoming friction in the ... by current flow through the windings D. transmitted directly through the rotor shaft to perform useful work
Last Answer : Answer: A
Description : The most effective method of locating a loose commutator bar in a D.C. motor is by _____________. A. visual inspection B. jiggling each by hand C. sounding each bar with a light weight hammer D. checking with a calibrated torque wrench
Last Answer : Answer: C
Description : In the illustrated motor, roller bearings are used because __________. EL-0001 A. of their ability to absorb moderate thrust loads B. they electrically insulate the rotor from the frame reducing ... clearance between the rotor and stator is generally as close as mechanical tolerance will permit
Last Answer : Answer: D
Description : The only point in the steering stand shown in the illustration which needs periodic lubrication is the ______________. EL-0098 A. repeater assembly ball bearings B. steering wheel bearing C. operation selector switch D. course selector pointer
Last Answer : Answer: B
Description : When changing fuses, you should always _____________. A. wear rubber boots B. use a fuse puller C. stand on a rubber mat D. wear safety glasses
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 : To protect the rotor of a motor disassembled for maintenance or overhaul, it should be ___________________. A. suspended by wire slings in one corner of the shop B. stowed upright on its shaft C. supported by two 'V' notched wood blocks D. returned to the frame as soon as the bearings are removed
Description : One of the generator or motor bearings is generally insulated from the end housing in order to prevent ________. A. rapid brush wear B. current leakage from the shaft C. excessive field winding heat D. circulation of shaft currents induced in the machine's frame
Description : Which of the following cannot tolerate misalignment? (a) Angular contact bearing (b) Cylinder roller bearing (c) Thrust ball bearings (d) All of the listed
Last Answer : (d) All of the listed
Description : Which of the bearings given below SHOULD NOT be subjected to a thrust load? (a) Deep groove ball bearing (b) Angular contact ball bearing (c) Cylindrical (straight) roller bearing (d) Single row tapered roller bearing
Last Answer : (c) Cylindrical (straight) roller bearing
Description : Antifriction bearings are (a) thick lubricated bearings (b) plastic bearings (c) ball and roller bearings (d) thin lubricated bearings
Last Answer : (c) ball and roller bearings
Description : Match List I with List II and select the : [IES-2002] List I (Bearings) List II (Load type) A. Hydrodynamic Journal bearing 1. High radial and thrust load combined B. Rectangular Hydrostatic bearing 2. Radial load only C. Taper Roller ... (a) 2 3 1 4 (b) 4 1 3 2 (c) 2 1 3 4 (d) 4 3 1 2
Last Answer : (a) 2 3 1 4
Description : Which of the following cannot tolerate misalignment? a) Angular contact bearing b) Cylinder roller bearing c) Thrust ball bearings d) All of the listed
Last Answer : d) All of the listed
Description : Temporary repairs to an open DC propulsion armature coil can be made by _____________. A. connecting the coil ends directly to a pair of negative brushes B. disconnecting coil ends, insulating ... C. grounding the coil ends and short circuiting the commutator bar D. removing the sparking brushes
Description : How do dogs know that burying their rawhide will make it soft and chewable?
Last Answer : answer:They’re just following centuries of instinct. When they were wolves, they didn’t want another pack member to get their bone so they buried it for safekeeping. I doubt that the right amount of time for seasoning it for proper “chewiness” entered into the picture :D
Description : Encrusted dirt accumulated inside a motor should be removed with a _____________. A. fiber scraper B. pointed welding rod C. hammer and chisel D. paint scraper
Description : A split-phase induction squirrel-cage motor will not come up to speed, even though the rated voltage, rated frequency, and rated load are applied. The suspected trouble could be due to _____________. A. a faulty centrifugal switch B. broken rotor bars C. worn bearings D. all of the above
Description : If the bearings of an electrical generator are failing more frequently than expected and the lubricating oil is sludging then you should ______________. A. check the connections to the output leads B. ... replace the bearing with a sealed roller type D. replace the thrust bearing of the prime mover
Description : On being hit with a hammer, __________ will readily fracture. (A) Brass (B) Mild steel (C) Cast iron (D) Lead
Last Answer : C) Cast iron
Description : Out of the following, which will fracture most readity, when hit with a hard hammer? (A) Brass (B) Bronze (C) German silver (D) Cast iron
Last Answer : Option D
Description : Ball bearings are used in cycles, scooters etc. to _____. A. Reduce the friction between the wheel and the axle B. Increase the friction between the wheel and the axle C. Reduce the friction between ground and the wheel D. None of these
Last Answer : ANSWER: A
Description : The function of ball bearings in a wheel is – (1) to increase friction (2) to convert kinetic friction into rolling friction (3) to convert static friction into kinetic friction (4) just for convenience
Last Answer : (2) to convert kinetic friction into rolling friction Explanation: A ball bearing is a type of rollingelement bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
Description : The function of ball bearings in a wheel is : (1) to increase friction (2) to convert kinetic friction into rolling friction (3) to convert static friction into kinetic friction (4) just for convenience
Last Answer : to convert kinetic friction into rolling friction
Description : The ball bearing is subjected to a radial load of 4000 N. Expected life for 90% bearings is 9000 hr and the shaft is rot (a) 42.21 kN (b) 37.29 kN (c) 26.33 kN (d) 35.22 kN
Last Answer : (b) 37.29 kN
Description : According to U. S. Coast Guard Regulations (46 CFR), the motor controller for a submersible electric motor driven bilge pump should be installed _____________. A. in the shaft alley B. at the submersible bilge pump C. above the uppermost continuous deck D. at the engine room emergency control panel
Description : The twisting force developed by a motor and applied to a shaft is called _____________. A. magnetism B. electromotive force C. torque D. voltage
Description : The direction of propeller shaft rotation in a turbo-electric synchronous propulsion drive motor is changed by reversing the _____________. A. polarity of the propulsion motor B. polarity of the propulsion generator C. phase sequence of power to the motor D. phase sequence of power to the generator
Description : The torque produced by a motor when its shaft will not turn, even though rated voltage is applied to the stator, is known as _____________. A. locked-rotor torque B. pullout torque C. breakdown torque D. torque margin
Description : Rotor shaft of a large electric motor supported between short bearings at both ends shows a deflection of 1.8 mm in middle of motor. Assuming rotor to be perfectly balanced and supported at knife edges at both ends, likely critical speed (rpm) of shaft isA 350 B 4430 C 705 D 2810
Last Answer : C 705
Description : On electrical generators one of the bearings is isolated from the bedplate. This insulating block should not be painted and must be kept clean to ___________. A. protect operating personnel from shock ... the prime mover as it warms up D. eliminate shaft currents to prevent damaging the bearings
Description : Before touching a small capacitor connected to a de-energized circuit, or even one that is completely disconnected, you should ____________. A. gently tap the body with a screwdriver B. tag it ... insulated fuse puller D. short circuit the terminals to make sure that the capacitor is discharged
Description : The speed of a squirrel cage induction motor is determined by the _____________. A. diameter of the stator B. number of stator poles C. rotor winding resistance D. bar resistance of the conducting rotor
Description : Which of the following is prone to cup and cone fracture? (A) Cast iron (B) Soft brass (C) Round specimen of ductile metal (D) Flat tensile specimen of ductile metal
Last Answer : Option C
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 : Wheat is ground into flour in a (A) Hammer crusher (B) Roller crusher (C) Impact mill (D) Fluid energy mill
Last Answer : (B) Roller crusher
Description : Where preloaded ball bearings used?
Last Answer : If more vibration exists even when machine is not in running conditions.
Description : What is the advantage of sliding bearings over roller bearings?
Last Answer : In roller bearing for a given movement the roller bearing exhibit a change in pressure centre from its original position by onehalf of its movement based on David J. Lee. However, with sliding ... built in the substructure. It follows that there is no change in pressure center after the movement.
Description : Which of the following elements is not used as a roller in roller bearings? (a) Cylindrical (b) Taper (c) Spherical (d) None of the mentioned
Last Answer : (d) None of the mentioned
Description : The piston pin bearings in heavy-duty diesel engines are (a) needle roller bearings (b) tapered roller bearings (c) spherical roller bearings (d) cylindrical roller bearings
Last Answer : (a) needle roller bearings
Description : The construction feature which makes tapered roller bearings unique in that races are (a) attachable (b) separable (c) self-aligning (d) none of the mentioned
Last Answer : (b) separable
Description : Tapered roller bearings can take (a) radial load only (b) axial load only (c) both radial and axial loads and the ratio of these being greater than unity (d) both radial and axial loads and the ratio of these being less than unity
Last Answer : (c) both radial and axial loads and the ratio of these being greater than unity
Description : Which of the following bearings carry thrust load in one direction? (a) Spherical roller thrust bearings (b) Taper roller bearings (c) Spherical roller thrust bearings and taper roller bearings (d) none of the mentioned
Last Answer : (c) Spherical roller thrust bearings and taper roller bearings
Description : In standard taper roller bearings, the angle of taper of the outer raceway is (a) 5° (b) 8° (c) 15° (d) 25°
Last Answer : (d) 25°
Description : The tapered roller bearings can take (a) radial load only (b) axial load only (c) both radial and axial loads (d) none of the mentioned
Last Answer : (c) both radial and axial loads
Description : Mostly long span rail-cum road bridges are provided with a) rocker & roller bearings b) segmental roller with oil bath* c) Sliding bearings d) centralised bearings
Last Answer : b) segmental roller with oil bath
Description : Bearings for plate girders are -- a) roller bearing b) sliding bearings c) centralised articulated bearings* d) None of the above
Last Answer : c) centralised articulated bearings*
Description : Ball bearings are generally made of (A) Plain carbon steel (B) Chrome carbon steel (C) Stainless steel (D) Malleable cast iron
Last Answer : (B) Chrome carbon steel
Description : Babbitt lining is used on brass/bronze bearings to increase the (A) Antifriction properties (B) Compressive strength (C) Bearing resistance
Description : A useful instrument for checking A.C. motor performance by measuring possible unbalanced currents is the _____________. A. hand or battery-operated megger B. vibrating-reed frequency meter C. hook-on voltmeter-ammeter D. D'Arsonval iron-vane probe
Description : One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for ... placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections