Calculate the bearing life if expected life for 90% bearings is 9000 hr and the shaft is rotating at 1500 rpm. (a) 850 million rev (b) 810 million rev (c) 810 hr (d) 850 hr

Calculate the bearing life if expected life for 90% bearings is 9000 hr and the shaft is rotating at 1500 rpm.

(a) 850 million rev

(b) 810 million rev

(c) 810 hr

(d) 850 hr
by

1 Answer

Answer :

(b) 810 million rev
by

Related questions

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

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

The static load is defined as the load acting on the bearing when the shaft is _____. (a) stationary (b) rotating at rpm<5 (c) rotating at rpm<10 (d) rotating at rpm<15

Description : The static load is defined as the load acting on the bearing when the shaft is _____. (a) stationary (b) rotating at rpm

Last Answer : (a) stationary

Static load is defined as the load acting on the bearing when shaft is _____ a) Stationary b) Rotating at rpm<10 c) Rotating at rpm<5 d) None of the listed

Description : Static load is defined as the load acting on the bearing when shaft is _____ a) Stationary b) Rotating at rpm

Last Answer : a) Stationary

Assertion (A): In steady rotating condition the journal inside a hydrodynamic journal bearing remains floating on the oil film. [IES-2008] Reason (R): The hydrodynamic pressure developed in steady rotating conditions in journal bearings balances the load on the journal. (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true but R is NOT the correct explanation of A (c) A is true but R is false (d) A is false but R is true

Description : Assertion (A): In steady rotating condition the journal inside a hydrodynamic journal bearing remains floating on the oil film. [IES-2008] Reason (R): The hydrodynamic pressure developed in steady rotating conditions in journal ... A (c) A is true but R is false (d) A is false but R is true

Last Answer : (a) Both A and R are true and R is the correct explanation of A

A full journal bearing having clearance to radius ratio of 1/100, using a lubricant with μ=28×10-3 Pa s supports the shaft journal running at N = 2400 rpm If bearing pressure is 1.4 MPa, the Somerfield number is [IES-2001] (a) 8×10-3 (b) 8×10-5 (c) 0.48 (d) 0.48×10

Description : A full journal bearing having clearance to radius ratio of 1/100, using a lubricant with μ=28×10-3 Pa s supports the shaft journal running at N = 2400 rpm If bearing pressure is 1.4 MPa, the Somerfield number is [IES-2001] (a) 8×10-3 (b) 8×10-5 (c) 0.48 (d) 0.48×10

Last Answer : (a) S = (μN s /p) (r/c) 2

Consider the following pairs of types of bearings and applications: 1. Partial Journal bearing................... Rail wagon axles 2. Full journal bearing ......................Diesel engine crank-shaft 3. Radial bearing ............................Combined radial and axial loads Which of these pairs is/are correctly matched? [IES-2000] (a) 1 alone (b) 1 and 2 (c) 2 and 3 (d) 1, 2 and 3

Description : Consider the following pairs of types of bearings and applications: 1. Partial Journal bearing................... Rail wagon axles 2. Full journal bearing ......................Diesel engine crank-shaft 3. Radial bearing ... matched? [IES-2000] (a) 1 alone (b) 1 and 2 (c) 2 and 3 (d) 1, 2 and 3

Last Answer : (b) 1 and 2

Which one of the following parts of a ball bearing is mounted on the rotating shafts and tends to rotate the shaft? (a) Inner race (b) Outer race (c) Rolling element (d) Cage

Description : Which one of the following parts of a ball bearing is mounted on the rotating shafts and tends to rotate the shaft? (a) Inner race (b) Outer race (c) Rolling element (d) Cage

Last Answer : (a) Inner race

Different types of bearings are designed to operate at different operating speeds. Speed is specified as the maximum (a) rpm (b) metres/second (c) metres/minute (d) metres/hour

Description : Different types of bearings are designed to operate at different operating speeds. Speed is specified as the maximum (a) rpm (b) metres/second (c) metres/minute (d) metres/hour

Last Answer : (b) metres/second

Assertion (A): In hydrodynamic journal bearings, the rotating journal is held in floating condition by the hydrodynamic pressure developed in the lubricant. Reason (R): Lubricant flows in a converging-diverging channel. [IES-1994] (a) Both A and R are individually true and R is the correct explanation of A (b) Both A and R are individually true but R is not the correct explanation of A (c) A is true but R is false (d) A is false but R is true

Description : Assertion (A): In hydrodynamic journal bearings, the rotating journal is held in floating condition by the hydrodynamic pressure developed in the lubricant. Reason (R): Lubricant flows in a converging-diverging channel. [IES-1994] ... A (c) A is true but R is false (d) A is false but R is true

Last Answer : (a) Both A and R are individually true and R is the correct explanation of A

The dynamic load-carrying capacity of a bearing is defined as the radial load in radial bearings that can be carried for a minimum life of 1000 revolutions. (a) True (b) False

Description : The dynamic load-carrying capacity of a bearing is defined as the radial load in radial bearings that can be carried for a minimum life of 1000 revolutions. (a) True (b) False

Last Answer : (b) False

The dynamic load carrying capacity of a bearing is defined as the radial load in radial bearings that can be carried for a minimum life of 1000 revolutions. a) True b) False

Description : The dynamic load carrying capacity of a bearing is defined as the radial load in radial bearings that can be carried for a minimum life of 1000 revolutions. a) True b) False

Last Answer : b) False

The rolling contact bearings as compared to sliding contact bearings have (a) small overall dimensions (b) accuracy of shaft alignment (c) low starting and low running friction except at very high speeds (d) all the mentioned

Description : The rolling contact bearings as compared to sliding contact bearings have (a) small overall dimensions (b) accuracy of shaft alignment (c) low starting and low running friction except at very high speeds (d) all the mentioned

Last Answer : (d) all the mentioned

Which of the following are functions of bearings? a) Ensure free rotation of shaft with minimum friction b) Holding shaft in a correct position c) Transmit the force of the shaft to the frame d) All of the listed

Description : Which of the following are functions of bearings? a) Ensure free rotation of shaft with minimum friction b) Holding shaft in a correct position c) Transmit the force of the shaft to the frame d) All of the listed

Last Answer : d) All of the listed

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

Match List -I (Bearings) with List-II (Applications) and select the using the codes given below the lists: [IAS-1998] List –I List-II A. Journal bearing 1. Electric motors B. Thrust bearing 2. Watches C. Conical pivot bearing 3. Marine engines D. Ball bearing 4. Swivelling chairs A B C D A B C D (a) 3 4 1 2 (b) 4 2 1 3 (c) 3 4 2 1 (d) 4 2 3 1

Description : Match List -I (Bearings) with List-II (Applications) and select the using the codes given below the lists: [IAS-1998] List -I List-II A. Journal bearing 1. Electric motors B. Thrust bearing 2. Watches C. Conical pivot bearing 3. Marine ... D (a) 3 4 1 2 (b) 4 2 1 3 (c) 3 4 2 1 (d) 4 2 3 1

Last Answer : (c) 3 4 2 1

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

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

______ is used for a shaft that supports rotating elements like wheels, drums or rope sleaves. a) Spindle b) Axle c) Shaf d) None of the listed

Description : ______ is used for a shaft that supports rotating elements like wheels, drums or rope sleaves. a) Spindle b) Axle c) Shaf d) None of the listed

Last Answer : a) Spindle

Shaft is rotating machine element. A. True B. False

Description : Shaft is rotating machine element. A. True B. False

Last Answer : A. True

______ is used for a shaft that supports rotating elements like wheels, drums or rope sleaves. a) Spindle b) Axle c) Shaf d) None of the listed

Description : ______ is used for a shaft that supports rotating elements like wheels, drums or rope sleaves. a) Spindle b) Axle c) Shaf d) None of the listed

Last Answer : a) Spindle

Consider the following statements: [IES 2007] For a journal rotating in a bearing under film lubrication conditions, the frictional resistance is- 1. Proportional to the area of contact 2. Proportional to the viscosity of lubricant 3. Proportional to the speed of rotation 4. Independent of the pressure Which of the statements given above are correct? (a) 1, 2, 3 and 4 (b) 1 and 4 only (c) 2, 3 and 4 only (d) 2 and 3 only

Description : Consider the following statements: [IES 2007] For a journal rotating in a bearing under film lubrication conditions, the frictional resistance is- 1. Proportional to the area of contact 2. Proportional to the viscosity of lubricant 3. ... 4 (b) 1 and 4 only (c) 2, 3 and 4 only (d) 2 and 3 only

Last Answer : (a) 1, 2, 3 and 4

The listed life of a rolling bearing, in a catalog is the, (a) minimum expected life (b) maximum expected life (c) average life (d) none of the mentioned

Description : The listed life of a rolling bearing, in a catalog is the, (a) minimum expected life (b) maximum expected life (c) average life (d) none of the mentioned

Last Answer : (a) minimum expected life

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

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

In a slider crank mechanism, the crank is rotating at 200 rpm. If length of connecting rod is 8 mts and crank shaft is 2 mts, velocity of crosshead at 30? rotation of crank shaft equals. a.30.2 m/s b.33.2 m/s c.35.8 mts/s d.107 dynes e.25.5 m/s

Description : In a slider crank mechanism, the crank is rotating at 200 rpm. If length of connecting rod is 8 mts and crank shaft is 2 mts, velocity of crosshead at 30? rotation of crank shaft equals. a.30.2 m/s b.33.2 m/s c.35.8 mts/s d.107 dynes e.25.5 m/s

Last Answer : e. 25.5 m/s

A shaft turns at 150 rpm under a torque of 1500 N-m. Power transmitted is (a) 15p kW (b) 10p kW (c) 7.5p kW (d) 5p kW (IES 1999) Hint: P = 2pNT/60

Description : A shaft turns at 150 rpm under a torque of 1500 N-m. Power transmitted is (a) 15p kW (b) 10p kW (c) 7.5p kW (d) 5p kW (IES 1999) Hint: P = 2pNT/60

Last Answer : (c) 7.5p kW

Which one of the following sets of parameters should be monitored for determining safe operation of journal bearing? [IES-2000] Oil pressure, bearing metal temperature and bearing vibration (b) Bearing vibration, oil pressure and speed of shaft (c) Bearing metal temperature and oil pressure (d) Oil pressure and bearing vibration

Description : Which one of the following sets of parameters should be monitored for determining safe operation of journal bearing? [IES-2000] Oil pressure, bearing metal temperature and bearing vibration (b) ... shaft (c) Bearing metal temperature and oil pressure (d) Oil pressure and bearing vibration

Last Answer : Oil pressure, bearing metal temperature and bearing vibration

Consider tile following statements: [IES-1993; 2002; 2006] Radius of friction circle for a journal bearing depends upon 1. Coefficient of friction 2. Radius of the journal 3. Angular speed of rotation of the shaft Which of the statements given above are correct? (a) 1,2 and 3 (b) Only 1 and 2 (c) Only 2 and 3 (d) Only 1 and 3

Description : Consider tile following statements: [IES-1993; 2002; 2006] Radius of friction circle for a journal bearing depends upon 1. Coefficient of friction 2. Radius of the journal 3. Angular speed of rotation of the shaft Which of the ... ) 1,2 and 3 (b) Only 1 and 2 (c) Only 2 and 3 (d) Only 1 and 3

Last Answer : (b) Only 1 and 2

Increase in values of which of the following results in an increase of the coefficient of friction in a hydrodynamic bearing? [IES 2007] 1. Viscosity of the oil. 2. Clearance between shaft and bearing. 3. Shaft speed. Select the using the code given below: (a) 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3

Description : Increase in values of which of the following results in an increase of the coefficient of friction in a hydrodynamic bearing? [IES 2007] 1. Viscosity of the oil. 2. Clearance between shaft and bearing. 3. Shaft speed. Select the ... 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3

Last Answer : (b) 1 and 3 only

In hydrodynamic bearing, when the shaft begins to rotate in clockwise direction, (A) The journal climbs to the right side of the bearing without metal to metal contact (B) The journal climbs to the left side of the bearing without metal to metal contact (C) The journal sinks down to the bottom of the bearing (D) The journal is at the center of the bearing

Description : In hydrodynamic bearing, when the shaft begins to rotate in clockwise direction, (A) The journal climbs to the right side of the bearing without metal to metal contact (B) The journal climbs to the left ... sinks down to the bottom of the bearing (D) The journal is at the center of the bearing

Last Answer : (A) The journal climbs to the right side of the bearing without metal to metal contact

Which of the following are not true for petroff’s equation? a) Shaft is considered concentric with the bearing b) Bearing is subjected to light load c) Is used to find coefficient of friction d) Frictional torque is given by fpr2l

Description : Which of the following are not true for petroff’s equation? a) Shaft is considered concentric with the bearing b) Bearing is subjected to light load c) Is used to find coefficient of friction d) Frictional torque is given by fpr2l

Last Answer : d) Frictional torque is given by fpr2l

A_______ bearing supports the load acting along the axis of the shaft. a) Thrust b) Radial c) Longitudinal d) Transversal

Description : A_______ bearing supports the load acting along the axis of the shaft. a) Thrust b) Radial c) Longitudinal d) Transversal

Last Answer : a) Thrust

A radial bearing supports the load that acts along the axis of the shaft. a) True b) False

Description : A radial bearing supports the load that acts along the axis of the shaft. a) True b) False

Last Answer : b) False

If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the diameter of each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. Permissible tensile stress is 80N/mm2. a) 27mm b) 25mm c) 23mm d) 21mm

Description : If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the diameter of each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. Permissible tensile stress is 80N/mm2. a) 27mm b) 25mm c) 23mm d) 21mm

Last Answer : a) 27mm

If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the tensile force on each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. a) 51234.4N b) 45968.3N c) 41666.7N d) None of the listed

Description : If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the tensile force on each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. a) 51234.4N b) 45968.3N c) 41666.7N d) None of the listed

Last Answer : c) 41666.7N

If shaft diameter is 40mm, calculate the length of sleeves in clamp coupling. a) 80mm b) 140mm c) 100mm d) 120mm

Description : If shaft diameter is 40mm, calculate the length of sleeves in clamp coupling. a) 80mm b) 140mm c) 100mm d) 120mm

Last Answer : b) 140mm

If shaft diameter is 40mm, calculate the diameter of sleeves in clamp coupling. a) 100mm b) 80mm c) 60mm d) 40mm

Description : If shaft diameter is 40mm, calculate the diameter of sleeves in clamp coupling. a) 100mm b) 80mm c) 60mm d) 40mm

Last Answer : a) 100mm

Calculate the shaft diameter on rigidity basis if torsional moment is 196000N-mm, length of shaft is 1000mm. Permissible angle of twist per meter is 0.5’ and take G=79300N/mm2. a) None of the listed b) 41.2mm c) 35.8mm d) 38.8mm

Description : Calculate the shaft diameter on rigidity basis if torsional moment is 196000N-mm, length of shaft is 1000mm. Permissible angle of twist per meter is 0.5’ and take G=79300N/mm2. a) None of the listed b) 41.2mm c) 35.8mm d) 38.8mm

Last Answer : b) 41.2mm

If shaft diameter is 40mm, calculate the length of sleeves in clamp coupling. a) 80mm b) 140mm c) 100mm d) 120mm

Description : If shaft diameter is 40mm, calculate the length of sleeves in clamp coupling. a) 80mm b) 140mm c) 100mm d) 120mm

Last Answer : b) 140mm

If shaft diameter is 40mm, calculate the diameter of sleeves in clamp coupling. a) 100mm b) 80mm c) 60mm d) 40mm

Description : If shaft diameter is 40mm, calculate the diameter of sleeves in clamp coupling. a) 100mm b) 80mm c) 60mm d) 40mm

Last Answer : a) 100mm

A rolling contact bearing is specified as X307. Calculate the bearing diameter. (a) 35 mm (b) 28 mm (c) 21 mm (d) 7 mm

Description : A rolling contact bearing is specified as X307. Calculate the bearing diameter. (a) 35 mm (b) 28 mm (c) 21 mm (d) 7 mm

Last Answer : (a) 35 mm

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

If a particle charges its angular velocity from 30 to 35 rpm in 20 seconds then it has angular acceleration of a.107 dynes b.30 rev/min2 c.10 rev/min2 d.20 rev/min2 e.15 rev/min2

Description : If a particle charges its angular velocity from 30 to 35 rpm in 20 seconds then it has angular acceleration of a.107 dynes b.30 rev/min2 c.10 rev/min2 d.20 rev/min2 e.15 rev/min2

Last Answer : e. 15 rev/min2

For the majority of bearings, actual life is considerably greater than rated life. (a) True (b) False

Description : For the majority of bearings, actual life is considerably greater than rated life. (a) True (b) False

Last Answer : (a) True

For majority of bearings, actual life is considerably greater than rated life. a) True b) False

Description : For majority of bearings, actual life is considerably greater than rated life. a) True b) False

Last Answer : a) True

A four-pole induction motor, operating on three-phase 60 cycle current will operate at approximately ___________. A. 850 RPM B. 1,150 RPM C. 1,750 RPM D. 3,550 RPM

Description : A four-pole induction motor, operating on three-phase 60 cycle current will operate at approximately ___________. A. 850 RPM B. 1,150 RPM C. 1,750 RPM D. 3,550 RPM

Last Answer : Answer: C

rank speed on the mower with conventional pit man drive is a)850-1000 rpm b)1000-1200rpm c)800-1150rpm d)1200-1600 rpm

Description : rank speed on the mower with conventional pit man drive is a)850-1000 rpm b)1000-1200rpm c)800-1150rpm d)1200-1600 rpm

Last Answer : a)850-1000 rpm

Calculate the Larmer angular frequency for a magnetic flux density of 12.34 x 10 -10 . a) 108.36 b) 810.63 c) 368.81 d) 183.36

Description : Calculate the Larmer angular frequency for a magnetic flux density of 12.34 x 10 -10 . a) 108.36 b) 810.63 c) 368.81 d) 183.36

Last Answer : a) 108.36