Question

A tractor has 1.6 m rear wheel diameter. If the e gear ratio of final drive and differential gear is 5:1 and 4:1 respectively calculate forward speed of tractor in kilometre per hour.

(a) 5.53

(b) 7.48

(c) 6.53

(d) 8.48

This question was posed to me in an interview for job.

The origin of the question is Mechanical Power Transmission topic in chapter Mechanical Power Transmission of Farm Machinery

Answer 1

Right choice is (a) 5.53

The explanation is: \(\frac{Ne}{Nr} \) = Gear box reduction*Gear ratio of final drive*Gear ratio of differential gear

\(\frac{1100}{Nr}=\frac{3}{1}*\frac{5}{1}*\frac{4}{1} \)

Nr=\(\frac{1100}{3*5*4}\) = 18.33 rpm

Forward speed of tractor = \(\frac{π*1.6*18.33}{60}\) = 5.53 kmph.