IN THIS VIDEO WE ARE DISCUSSING ABOUT PREVIOUS YEARS GATE QUESTIONS ON BEARING

1. GATE QUESTION ON BEARING
FOR GATE,PSU,INTERVIEW
THEGATEMECH

2. GATE 2014
1. Ball Bearing are rated by a manufacturer for a life of 10^6 revolution. The
catalog rating for particular bearing is 16KN. If the design load is 2KN, the life
of bearing will be P X 10^6 rev. where P = ______________ ?
ANSWERwhere C = 16 KN
W = 2 KN
L10 = (C/W)^K
L10 = (16/2)^3
P = L10 = 512 X 10^6 = 512 Million Revolution

3. GATE 2016
2 Which of the bearing given below should not be subjected to thrust load ?
A. DGBB
B. ACBB
C. CRB
D. SRB
ANSWERC

4. GATE 2015
3. For ball bearing, the fatigue life measured in number of rev. & the radial load F
are related by FL^1/3 = K, where K = Constant. It withstand a radial load of 2
KN for a life of 540 Million rev. is __________________ ?
ANSWERGiven FL^1/3 = K
F1L1^1/3 = F2L2^1/3
2 X 540^1/3 = F2 X 1^1/3
F2 = 16.29 KN

5. 4 Two ball bearing P & Q are operating at loads 30 KN & 45 KN res. The ratio of
life of bearing P to the life of bearing Q is _____________ ?
ANSWERL = 1/F^K = 1/F^3
LP/LQ = (FQ/FP)^3 = (45/30)^3
LP/LQ = 91125/27000
LP/LQ = 27/8

6. 5 A ball bearing at a load F has 8000 hrs. of life. The life of the bearing in hr.
when the load is 2F __________?
ANSWERwhen load is F then life is 8000 hrs.
L = 1/F^3
L1F1^3 = L2F2^3
8000 X F^3 = L2 X (2F)^3
L2 = 1000 hrs.

7. 6 A DGBB rotating at 1200 rpm is subjected to radial and an axial force of 2000 N &
1500 N res. What will be the dynamic load capacity of bearing if 20,000 hrs. is the
rating life ?
ANSWERXO = 0.55
YO = 2
Ka = 1.5
N = 1200 rpm
WR = 2 N
WA = 1.5 KN
L10h = 20,000
W = (XOVWR + YOWA) Ka
W = 6.15 KN
L10 = (60 X N X L10h)/10^6
L10 = (C/W)^3
C = 69.45 KN

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