MAXIMUM TENSION IN THE BELT IS ALWAYS THREE TIMES THE CENTRIFUGAL T...
3. Maximum tension in the belt is always three times the centrifugal
tension.
Which of the statements given above is/are correct?
Design of Friction Drives
S K Mondal’s
Chapter 2
(a) 1, 2 and 3
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1 only
IES-36Ans. (b)
IES-37. In case of belt drives, the effect of the centrifugal tension is to: [IES-2006]
(a) Cause the belt to leave the pulley and increase the power to be transmitted
(b) Cause the belts to stay on the pulley and increase the power to be transmitted
(c) Reduce the driving power of the belt
(d) Stretch the belt in longitudinal direction
IES-37Ans. (d) Centrifugal tension has no effect on the power to be transmitted.
Condition for maximum powerIES-38. In a flat belt drive the belt can be subjected to a maximum tension T and
centrifugal tension T
c
. What is the condition for transmission of maximum
power?
[IES-2008]
(a)
T=T
c
(b)
T=
3
T
c
(c)
T=2T
c
(d)
T=3T
c
IES-38Ans. (d)
Condition for maximum power transmission:-
(
)
=
−
P
T
T v
1
2
T
e
μθ
=
1
T
2
⎛
⎞
P
T
T
1
1
v
⇒
=
−
⎜
⎝
−
⎟
⎠
max
c
e
( )P
T
v mv 1
1
max
3
⇒
=
−
−
dP
T
3mv
0
⇒
=
−
=
max
dv
mv
T
2
max
⇒
=
3
T
T
c
max
∴
=
T
3T
IES-39. Which one of the following statements with regard to belt drives is NOT
correct?
[IES-2000]
(a) Increase in the angle of wrap of the belt enables more power transmission
(b) Maximum power is transmitted when the centrifugal tension is three times the
tight side tension
(c) Wide and thin belt is preferable for better life than a thick and narrow one
(d) Crown is provided on the pulley to make the belt run centrally on the pulley
IES-39.Ans. (b)
IES-40. When a belt drive is transmitting maximum power
[IES-1996]
(a) Effective tension is equal to centrifugal tension.
(b) Effective tension is half of centrifugal tension.
(c) Driving tension on slack side is equal to the centrifugal tension.
(d) Driving tension on tight side is twice the centrifugal tension.
IES-40Ans. (d)
IES-41. The power transmitted by a belt is dependent on the centrifugal effect in
the belt. The maximum power can be transmitted when the centrifugal
tension is
[IES-2002]
(a) 1/3 of tension (T
1
) on the tight side
(b) 1/3 of total tension (T
t
) on the tight side
(c) 1/3 of tension (T
2
) on the slack side
(d) 1/3 of sum of tensions T
1
and T
2
i.e. 1/3 (T
1
+ T
2
)
IES-41Ans. (b)
Selection of V-belt driveIES-42. Assertion
(A): For similar materials having the same maximum permissible
tension V-belt transmits more power than flat belt with same velocity ratio and
centre distance.
[IES-2001]
Reason
(R): As two sides of V-belt are in contact with side faces of pulley groove,
larger contact area gives greater effective frictional force.
(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
IES-42Ans. (a)
IES-43. In a multiple V belt drive, when a single belt is damaged, it is preferable to
change the complete set to
[IES-1993]
(a) Reduce vibration
(b) reduce slip
(c) Ensure uniform loading
(d) ensure proper alignment
IES-43Ans. (c) If a single belt breaks, all belts arc replaced to ensure uniform loading.
IES-44. Consider
the
following:
V-belts are specified by their
[IES-2008]