Question

In a band brake, the coefficient of friction is 0.35, width of the band is 70 mm, diameter is 75 mm and angle of overlap of band on the drum is 180${}^{\circ }$. The normal pressure between the drum and the lining is to be limited to 0.3 MPa. The tension on the tight side is _________ N.

• A. 687.5
• B. 887.5
• C. 987.5
• D. 787.5

Answer 1

The correct option is D 787.5

$\frac{T_1}{T_2}=e^{(0.35\times \pi )}$

$\frac{T_1}{T_2}=3----\left(i\right)$

$P=\frac{2T}{D\times W}$

$P_{max}=\frac{2T_{max}}{75\times 70}=\frac{2T_1}{75\times 70}=0.3$

$T_1=0.3\times 70\times 75=787.5N$