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 cross-currents C. the shafting and end bells do not require as close a tolerance to properly fit this type of bearing D. the clearance between the rotor and stator is generally as close as mechanical tolerance will permit

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 cross-currents C. the shafting and end bells do not require as close a tolerance to properly fit this type of bearing D. the clearance between the rotor and stator is generally as close as mechanical tolerance will permit  
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Answer: D
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Related questions

In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction motor C. is the armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor

Description : In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction ... armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor

Last Answer : Answer: B

As shown in the illustration, the purpose of the item labeled 'Z', in assembly No. 2, is to _____________. EL-0001 A. keep the rotor in balance B. align the rotor to the stator C. dynamically balance the rotor D. cool the motor

Description : As shown in the illustration, the purpose of the item labeled 'Z', in assembly No. 2, is to _____________. EL-0001 A. keep the rotor in balance B. align the rotor to the stator C. dynamically balance the rotor D. cool the motor

Last Answer : Answer: D

The purpose of the item labeled 'Z' in assembly No. 2, shown in the illustration is to _____________. EL-0001 A. keep the rotor in balance B. align the rotor to the stator C. dynamically balance the rotor D. cool the motor

Description : The purpose of the item labeled 'Z' in assembly No. 2, shown in the illustration is to _____________. EL-0001 A. keep the rotor in balance B. align the rotor to the stator C. dynamically balance the rotor D. cool the motor

Last Answer : Answer: D

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. check the bearing insulating block on one end of the unit C. replace the bearing with a sealed roller type D. replace the thrust bearing of the prime mover

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

Last Answer : Answer: B

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 : 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

Last Answer : Answer: D

Tapper roller bearing are used in disc harrow because a) It can take heavy radial loads b) It can take both radial as well as end thrust c) It can operate effectively at low speed and in contact with dirt d) Both (b) and (c) are true

Description : Tapper roller bearing are used in disc harrow because a) It can take heavy radial loads b) It can take both radial as well as end thrust c) It can operate effectively at low speed and in contact with dirt d) Both (b) and (c) are true

Last Answer : d) Both (b) and (c) are true

The antifriction bearings (a) have low starting and low running friction at moderate speeds (b) have a high initial cost (c) can carry both radial and thrust loads (d) all the mentioned

Description : The antifriction bearings (a) have low starting and low running friction at moderate speeds (b) have a high initial cost (c) can carry both radial and thrust loads (d) all the mentioned

Last Answer : (d) all the mentioned

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 bearing 3. Thrust load only D. Angular contact ball bearing 4. Medium to low radial and thrust combined A B C D A B C D (a) 2 3 1 4 (b) 4 1 3 2 (c) 2 1 3 4 (d) 4 3 1 2

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

When disassembling electric motors for maintenance or overhaul, ________________. A. punch mark frame and end bells for proper assembly B. wrap bearings in lint free cloths if they are to be reused C. tag and store small parts in a box D. all of the above

Description : When disassembling electric motors for maintenance or overhaul, ________________. A. punch mark frame and end bells for proper assembly B. wrap bearings in lint free cloths if they are to be reused C. tag and store small parts in a box D. all of the above

Last Answer : Answer: D

The air gap in an induction motor should be periodically checked with a feeler gage to prevent possible ___________. A. rotor contact with the stator B. axial misalignment of the rotor C. damage to the motor bearings D. electrical damage to the bearings

Description : The air gap in an induction motor should be periodically checked with a feeler gage to prevent possible ___________. A. rotor contact with the stator B. axial misalignment of the rotor C. damage to the motor bearings D. electrical damage to the bearings

Last Answer : Answer: A

Which of the following cannot tolerate misalignment? (a) Angular contact bearing (b) Cylinder roller bearing (c) Thrust ball bearings (d) All of the listed

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

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

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

Which of the following cannot tolerate misalignment? a) Angular contact bearing b) Cylinder roller bearing c) Thrust ball bearings d) All of the listed

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

In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors

Description : In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors

Last Answer : Answer: C

In the illustration, the assembly labeled 2 is a ________. EL-0001 A. wound rotor and shaft for a single phase induction motor B. conduction rotor and shaft for a polyphase induction motor C. squirrel cage rotor and shaft for a polyphase motor D. squirrel cage rotor for a single phase induction motor

Description : In the illustration, the assembly labeled 2 is a ________. EL-0001 A. wound rotor and shaft for a single phase induction motor B. conduction rotor and shaft for a polyphase induction motor C. ... cage rotor and shaft for a polyphase motor D. squirrel cage rotor for a single phase induction motor

Last Answer : Answer: C

The bearings which resist radial loads is known as a) Ball bearing b) bush bearing c) thrust bearing d) journal bearing

Description : The bearings which resist radial loads is known as a) Ball bearing b) bush bearing c) thrust bearing d) journal bearing

Last Answer : d) journal bearing

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 : 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

Last Answer : Answer: C

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. wrapped in several layers of heavy paper or cardboard C. supported by flat wood blocks on the workbench D. returned to the frame as soon as the bearings are removed

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. wrapped in several layers of heavy ... flat wood blocks on the workbench D. returned to the frame as soon as the bearings are removed

Last Answer : Answer: B

The torque and current curves for a three-phase induction motor with a cage rotor, are shown in the illustration. Which of the following statements is true concerning the depicted curves? EL-0056 A. As slip increases, rotor reactance decreases. B. The pullout point on the torque curve is about seven times the normal full load torque value. C. At stand still, stator current is 150% of normal. D. If the motor is loaded to the point where 40% slip has resulted, it will stall.

Description : The torque and current curves for a three-phase induction motor with a cage rotor, are shown in the illustration. Which of the following statements is true concerning the depicted curves? EL-0056 A. As slip ... D. If the motor is loaded to the point where 40% slip has resulted, it will stall.

Last Answer : Answer: D

Routine A.C. motor maintenance should include periodic ______________. A. thermometer readings at normal loads to detect abnormal temperature rises B. inspection of the motor's internals for loose rotor bars or field poles C. bearing replacement each year using sealed units if available D. all of the above

Description : Routine A.C. motor maintenance should include periodic ______________. A. thermometer readings at normal loads to detect abnormal temperature rises B. inspection of the motor's internals for loose rotor bars ... C. bearing replacement each year using sealed units if available D. all of the above

Last Answer : Answer: A

On large generators, space heaters are used to ____________. A. keep the machine at ambient tmperature of the machinery space B. maintain rotor and stator winding temperatures above the dew point to prevent the formation of condensation C. prevent condensation in the lube oil D. prevent electrolysis due to condensation in the bearings

Description : On large generators, space heaters are used to ____________. A. keep the machine at ambient tmperature of the machinery space B. maintain rotor and stator winding temperatures above the dew point ... C. prevent condensation in the lube oil D. prevent electrolysis due to condensation in the bearings

Last Answer : Answer: B

Air gap readings for electrical generating equipment should be taken periodicly. This is to _______. I. determine the condition of the bearings II. prevent damage to the rotor and stator A. I only B. II only C. both I and II D. neither I or II

Description : Air gap readings for electrical generating equipment should be taken periodicly. This is to _______. I. determine the condition of the bearings II. prevent damage to the rotor and stator A. I only B. II only C. both I and II D. neither I or II

Last Answer : Answer: C

Using illustrated chart, when will the power factor be least efficient? EL-0006 A. When the motor is operating at full load. B. When the percentage of slip is greatest. C. When there is no load on the motor. D. the power factor is the same from no-load to locked rotor.

Description : Using illustrated chart, when will the power factor be least efficient? EL-0006 A. When the motor is operating at full load. B. When the percentage of slip is greatest. C. When there is no load on the motor. D. the power factor is the same from no-load to locked rotor.

Last Answer : Answer: C

The rotor slots of a repulsion-type motor are generally skewed (placed nonparallel to the rotor axis) to _________. A. produce a constant starting torque B. permit a greater air gap with the starter C. permit a smaller air gap with the starter D. reduce eddy current losses

Description : The rotor slots of a repulsion-type motor are generally skewed (placed nonparallel to the rotor axis) to _________. A. produce a constant starting torque B. permit a greater air gap with the starter C. permit a smaller air gap with the starter D. reduce eddy current losses

Last Answer : Answer: A

If air gap readings for an electical generating machine have changed significantly from the last reading, you should check _________. A. the bearings B. insulation readings and machine cleanliness C. the prime mover thrust bearing D. the field coil bolts for the proper torque values

Description : If air gap readings for an electical generating machine have changed significantly from the last reading, you should check _________. A. the bearings B. insulation readings and machine cleanliness C. the prime mover thrust bearing D. the field coil bolts for the proper torque values

Last Answer : Answer: A

The speed of a squirrel-cage, multi-speed, induction motor, as used aboard ship, is varied by changing the __________. A. number of connected poles in the stator B. frequency to the motor C. excitation voltage D. resistance of the rotor circuit

Description : The speed of a squirrel-cage, multi-speed, induction motor, as used aboard ship, is varied by changing the __________. A. number of connected poles in the stator B. frequency to the motor C. excitation voltage D. resistance of the rotor circuit

Last Answer : Answer: A

The rotor of a synchronous motor operates in synchronism with the rotating field because ______________. A. of the amortisseur windings B. the rotor is magnetically locked into step with the rotating magnetic field by the excitation current C. the field strength varies directly with rotor slip D. the stator flux rotates in the opposite direction

Description : The rotor of a synchronous motor operates in synchronism with the rotating field because ______________. A. of the amortisseur windings B. the rotor is magnetically locked into step with the ... field strength varies directly with rotor slip D. the stator flux rotates in the opposite direction

Last Answer : Answer: B

A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor magnets to lock in with the rotating flux of the stator C. the stator poles are dragged around due to the flux created by the excitation current D. the stator flux rotates in the opposite direction

Description : A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor ... the flux created by the excitation current D. the stator flux rotates in the opposite direction

Last Answer : Answer: B

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

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

When using a megohmmeter to determine which shunt field coil is grounded in a DC machine, you must ____________. A. insulate the field frame from the ship's hull B. disconnect each shunt field coil before testing C. use a motor driven high capacity megohmmeter D. remove all main line lead connections before testing

Description : When using a megohmmeter to determine which shunt field coil is grounded in a DC machine, you must ____________. A. insulate the field frame from the ship's hull B. disconnect each shunt ... C. use a motor driven high capacity megohmmeter D. remove all main line lead connections before testing

Last Answer : Answer: B

On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________. A. insulation resistance B. eddy currents C. capacitance D. armature reactance

Description : On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________. A. insulation resistance B. eddy currents C. capacitance D. armature reactance

Last Answer : Answer: A

If the three-phase motor, shown in the illustrated schematic diagram, is running in the forward direction, which of the following actions must occur before the motor will reverse rotation? EL-0011 A. Normally-closed contacts '4'-'5' must open. B. Normally- open contacts '2'-'3' must close. C. 'L1' and 'L3' must be interchanged via the 'R' contacts. D. All of the above.

Description : If the three-phase motor, shown in the illustrated schematic diagram, is running in the forward direction, which of the following actions must occur before the motor will reverse rotation? EL-0011 A. Normally-closed ... 'L1' and 'L3' must be interchanged via the 'R' contacts. D. All of the above.

Last Answer : Answer: C

Deep groove ball bearings are used for (a) heavy thrust load only (b) the small angular displacement of shafts (c) radial load at high speed (d) combined thrust and radial loads at high speed

Description : Deep groove ball bearings are used for (a) heavy thrust load only (b) the small angular displacement of shafts (c) radial load at high speed (d) combined thrust and radial loads at high speed

Last Answer : (d) combined thrust and radial loads at high speed

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

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

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

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

One of the generator bearing shells is generally insulated from the end housing in order to prevent _____________. A. rapid brush wear B. residual magnetism leak off C. excessive field winding heat D. circulation of shaft currents

Description : One of the generator bearing shells is generally insulated from the end housing in order to prevent _____________. A. rapid brush wear B. residual magnetism leak off C. excessive field winding heat D. circulation of shaft currents

Last Answer : Answer: D

The following air gap readings were obtained from a horizontally mounted, bilge pump, induction motor, equipped with sleeve bearings: FWD END-AFT END, Top .045 - .049, Right Side .045 - .047, Left Side .045 - .047, Bottom .045 - .041 Which of the f A. both the aft and foward bearings should be replaced. B. Shims should be removed from the aft bearing. C. The forward bearing should be lowered. D. The aft bearing should be lowered.

Description : The following air gap readings were obtained from a horizontally mounted, bilge pump, induction motor, equipped with sleeve bearings: FWD END-AFT END, Top .045 - .049, Right Side .045 - .047, Left ... the aft bearing. C. The forward bearing should be lowered. D. The aft bearing should be lowered.

Last Answer : Answer: A

The following air gap readings were obtained from a horizontally mounted, bilge pump, induction motor, equipped with sleeve bearings: FWD END -AFT END, Top .045 - .049 , Right Side .045 - .047, Left Side .045 - .047 , Bottom .045 - .041 Which of the fo A. The aft bearing should be realigned or replaced. B. Shims should be removed from the aft bearing. C. The forward bearing should be lowered. D. The aft bearing should be lowered.

Description : The following air gap readings were obtained from a horizontally mounted, bilge pump, induction motor, equipped with sleeve bearings: FWD END -AFT END, Top .045 - .049 , Right Side .045 - .047, Left ... the aft bearing. C. The forward bearing should be lowered. D. The aft bearing should be lowered.

Last Answer : Answer: A

In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage supply to the stator windings C. laminated steel core and aluminum conductors in the rotor D. interaction of the magnetic field caused by the induced current in the squirrel-cage bars with the magnetic field of the stator

Description : In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage ... caused by the induced current in the squirrel-cage bars with the magnetic field of the stator

Last Answer : Answer: B

The speed of a three-phase squirrel-cage induction-type motor operating in a fixed frequency system is varied by changing the _____________. A. number of phases to the motor B. number of stator poles C. locked rotor current D. resistance of the rotor winding

Description : The speed of a three-phase squirrel-cage induction-type motor operating in a fixed frequency system is varied by changing the _____________. A. number of phases to the motor B. number of stator poles C. locked rotor current D. resistance of the rotor winding

Last Answer : Answer: B

A 1.8°step, 4-phase stepper motor has a total of 40 teeth on 8 pole of stator. The number of rotor teeth for their rotor will be (A) 40 (B) 50 (C) 100 (D) 80

Description : A 1.8°step, 4-phase stepper motor has a total of 40 teeth on 8 pole of stator. The number of rotor teeth for their rotor will be (A) 40 (B) 50 (C) 100 (D) 80

Last Answer : (B) 50

Match List-I (Type of Anti-friction bearing) with List-II (Specific Use) and select the using the code given below the Lists: [IES-2006] List-I List -II A. Self-aligning ball bearing 1. For pure axial load B. Taper roller bearing 2. For hinged condition C. Deep groove ball bearing 3. For pure radial load D. Thrust ball bearing 4. For axial and radial load A B C D A B C D (a) 2 1 3 4 (b) 3 4 2 1 (c) 2 4 3 1 (d) 3 1 2 4

Description : Match List-I (Type of Anti-friction bearing) with List-II (Specific Use) and select the using the code given below the Lists: [IES-2006] List-I List -II A. Self-aligning ball bearing 1. For pure axial load B. Taper roller bearing 2. For ... C D (a) 2 1 3 4 (b) 3 4 2 1 (c) 2 4 3 1 (d) 3 1 2 4

Last Answer : (c) 2 4 3 1

When removing ball or roller bearings from the shaft of a motor, you should use a _____________. A. rawhide hammer B. brass mallet C. wheel puller D. soft iron pry bar

Description : When removing ball or roller bearings from the shaft of a motor, you should use a _____________. A. rawhide hammer B. brass mallet C. wheel puller D. soft iron pry bar

Last Answer : Answer: C

The speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system can be changed by _____________. A. reconnecting stator windings for different numbers of poles B. changing the RPM of the rotor flux C. changing the phase sequence of the applied voltage D. reconnecting the stator so that no poles have the same polarity

Description : The speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system can be changed by _____________. A. reconnecting stator windings for different numbers of poles B. ... sequence of the applied voltage D. reconnecting the stator so that no poles have the same polarity

Last Answer : Answer: A

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. rotor conducting bars resistance

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. rotor conducting bars resistance

Last Answer : Answer: B

Regarding an induction motor, the power developed by the rotor automatically adjusts itself to the _____________. A. power required to drive the load B. speed required to drive the load C. current flow in the motor stator D. torque developed by the rotating field

Description : Regarding an induction motor, the power developed by the rotor automatically adjusts itself to the _____________. A. power required to drive the load B. speed required to drive the load C. current flow in the motor stator D. torque developed by the rotating field

Last Answer : Answer: A

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 : 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

Last Answer : Answer: B

The purpose of amortisseur windings in a synchronous motor is to ______________. A. reduce eddy current losses B. produce a higher power factor C. provide a means for starting D. eliminate arcing between the stator and the rotor

Description : The purpose of amortisseur windings in a synchronous motor is to ______________. A. reduce eddy current losses B. produce a higher power factor C. provide a means for starting D. eliminate arcing between the stator and the rotor

Last Answer : Answer: C

Amortisseur windings are installed in a synchronous motor to _____________. A. reduce eddy current losses B. produce a higher power factor C. provide a means for starting D. eliminate arcing between the stator and the rotor

Description : Amortisseur windings are installed in a synchronous motor to _____________. A. reduce eddy current losses B. produce a higher power factor C. provide a means for starting D. eliminate arcing between the stator and the rotor

Last Answer : Answer: C