A band brake having bandwidth of 80 mm, drum diameter of

A band brake having bandwidth of 80 mm, drum diameter of 250 mm, coefficient of friction of 0.25 and angle of wrap of 270 degrees is required to exert a friction torque of 1000 N m. The maximum tension (in kN) developed in the band is

Given: b = 80 mm = 0.08 m D = 250 mm = 0.25

R =	D	= 0.25
	2

μ = 0.25

θ = 270° = 270 ×	π	= 4.712 radians
	180

F_t = 100 N-m

As	p₁	= e^μθ
	p₂

⇒ p₁ = e^μθ ⋅ p₂ = e^{0.25 × 4.712} ⋅ p₂ = 3.25p₂
Now, F_t = (p₁ − p₂)R

∴ 1000 =		p₁ −	p₁		0.125
			3.25

Solving, we get maximum tension in the belt,
p₁ = 11.56 kN