What is the operating life of bearings? 

1 Answer

Answer :

a) Continuous 24 hrs operation – 40000 to 50000 hrs.

b) Affected by load axially or radial.

c) Operating temperature. 


Related questions

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

Last Answer : Answer: D

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

Description : Under normal operating conditions, the bearings are filled with the proper type of lubricant after every hours of working about a) 6 hours b) 8 hoursc) 10 hours d) 12 hours

Last Answer : c) 10 hours

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

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

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

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

Description : Air gap readings should be taken on electrical generation machinery periodicly to _________. I. determine the need for cleaning II. check the condition of the bearings A. I only B. II only C. both I and II D. neither I or II

Last Answer : Answer: B

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

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

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

Last Answer : Answer: D

Description : Air gap readings should be taken periodicly on electrical generation equipment to __________. A. determine the amount of varnish that can be applied to correct insulation problems B. determine the ... field coil bolts and correct lateral adjustment of the field coils D. increase machine efficiency

Last Answer : Answer: B

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

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

Last Answer : Answer: D

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

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 : 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

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

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 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

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

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 : 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

Last Answer : Answer: C

Description : What are the causes of failure of bearings?

Last Answer : a) Faulty mounting b) Faulty lubrication c) Foreign matter in lubrication d) Water in the bearing arrangement e) Vibration f) Inoccurrences of form of shaft or housing seating. g) Passage of electric current. h) Metal fatigue

Description : Which bearings preferred for all large power motor?  

Last Answer : Plain bearings  

Description : Why do we grease the bearings?

Last Answer : a) Grease lubricant gives good protection against ingress of moisture and dirt into motor. b) Easy to seal against leakage of grease into motor compared to oil. c) Low friction torque at starting. 

Description : Where preloaded ball bearings used? 

Last Answer : If more vibration exists even when machine is not in running conditions.  

Description : What are the types of bearings are adopted for small motors and large motors?

Last Answer : Small motors (LT motors) Horizontal mounted - deep groove ball bearing at both ends. Medium motors Roller bearing at DE and deep groove bearing at NDE. Large motors (HT motors above 750 kW) Horizontal ... mounted - face to face angular contact ball bearing at NDE and roller or ball bearing at DE.

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 : 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

Last Answer : (b) 810 million rev

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

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

Last Answer : (a) True

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

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

Last Answer : a) True

Description : When did the first ball bearings Skates came into life?

Last Answer : Ans. December 9th 1884.

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

Last Answer : Answer: A

Description : Is my Alternator/Alternator Bearings going out? Strange noise when accelertaing?

Last Answer : It’s entirely possible that improper tension (Overtightening in this case) could shred the bearings in your alternator.

Description : How do I rejuvinate ball bearings?

Last Answer : If they are ceramic, forget it. They are toast. If they are steel you can soak them in kerosene to get rid of the bits and old grease and then repack with new grease . If you don’t have kerosene you can spray with carb cleaner. (The link I included is for cars but it is still true for longboards.)

Description : Skateboard bearings?

Last Answer : answer:Have you checked the Bones website? I ride Swiss Ceramics, but I wouldn’t mind peepin’ those Labyrinths!

Description : Ball bearings are used in cycles, scooters etc to -Physics

Last Answer : Reduce the friction between the wheel and the axle.

Description : I bought a 1984 blazer it had a 350 numbers 10243880 it fired up but knocked i pulled the oil pan and one bearing spun can I just replace the spun bearing only and go or all bearings also it's supposed to be fuel injected but mine is carburated TIA?

Last Answer : Oops the K5 blazer is a 91 not an 84 I found out the year of the motor was 96 to 2000 but I need information on fixing the bearings

Description : What size socket do you need to change the wheel bearings on 1998 GMC Jimmy front and back axles?

Last Answer : Need to know if 2 wheel or 4 wheel drive for the front. Eitherway, there is no nut on the back axles.

Description : Where can I get new wheel bearings?

Last Answer : The best place to get any auto parts or wheel bearings is from your auto car dealer, or Canadian tire they should have you wanted. From what I gather no prices were posted online.

Description : Where can I get vehicle bearings for my vehicle?

Last Answer : I think best solution would be to contact a local dealership or trusted shop which sell car parts. I would also visit trusted car mechanic if I was looking for new bearings.

Description : What is the use of YRT rotary table bearings?

Last Answer : YRT rotary table bearings is particularly suitable for the situation of high precision, high stiffness, low speed, and short rotate period such as rotary table, index heads ,5 axis machining centers and revolving milling heads. #HONBbearing07 #hyzcbearing

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 : Polytetrafluoroethylene (PTFE) is commonly used in sliding bearings. Why?

Last Answer : The choice of sliding surface of bearings is of vital importance because the sliding surfaces generate frictional forces which are exerted on the bearings and substructure of the bridge. For ... be designed with dimples to avoid the lubricant from squeezing out under repeated translation movements.

Description : Under what situation should engineers use pot bearings instead of elastomeric bearings?

Last Answer : In the event of high vertical loads combined with large angle of rotations, rubber bearings are undesirable when compared with pot bearings. For instance, elastomeric ... bearings are better alternatives than elastomeric bearings in such an scenario as suggested by David J. Lee.

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.