Question:-
A band brake having band-width of 80mm, drum diameter of 250mm, coefficient of friction of 0.25 and angle of wrap of 270 degrees is required to exert a friction torque of 1000N-m. The maximum tension (in kN) developed in the band is
Option (A)
1.88
Option (B)
3.56
Option(C)
6.12
Option(D)
11.56
Correct Option:
(D)
Question Solution:
b = 80mm; D=250mm; m = 0.25; q = 270dgrees = 4.712 rad; Ft = 1000 N-m We know that Ft = (p1 - p2)R

(P1/p2) = emq, p1 = emq. P2 = e0.25x4.712. P2, p1 = 3.25p2

\ 2.25p2 = (Ft /R) = (1000 / 0.125) Þ p2 = 3.5KN

And P1=11.56 KN

Therefore Max tension in the belt = 11.56 KN.
question-answer-faq-2365