Question

The width of belt is 15 cm and maximum tension per cm width is not to exceed 12 kg. T1/T2=2.25. Diameter of driver=1m and it makes 220 rpm. Find the horse power that can be transmitted.

(a) 11.35 HP

(b) 10.23 HP

(c) 12.12 HP

(d) 9.86 HP

I got this question at a job interview.

This intriguing question comes from Numerical Problems on Calculation of Different Tractor Parameters topic in chapter Lubrication System and Tractor’s Classification of Farm Machinery

Answer 1

Correct answer is (b) 10.23 HP

To explain I would say: Maximum tension = 12 * 15 = 180kg

We know that

T = T1 + TC = 180

And, Tc = T/3

Tc = 180/3 = 60 kg

T1 = T-Tc = 180 – 60 = 120kg

T2 = T1/2.5 = 120/2.25 = 53.33 kg

P = (T1-T2) v = (T1 – T2) * 2π Nr

P = (120 – 53.33) * 2\pi * \(\frac{220}{75*60}*\frac{1}{2} \)

P = 10.23 HP.