Question

Find the gear ratio of a tractor of its final drive of tractor has 1.2 m tractor wheel and forward speed of 5km/h. When engine is running at 1000 rpm if reduction in transmission is 3:1

(a) 4.3:1

(b) 3.3:1

(c) 2.3:1

(d) 5.3:1

I have been asked this question in an international level competition.

My doubt is from Numerical Problems on Calculation of Different Tractor Parameters in portion Lubrication System and Tractor’s Classification of Farm Machinery

Answer 1

Correct choice is (a) 4.3:1

For explanation: Actual speed of tractor (va) = \(\frac{5*5*60}{18}\)  = 83.33 m/min

va = rω = r.2πN

N = \(\frac{v}{2πr}=\frac{83.33}{2π*0.6}\) = 22.11

G.r = \(\frac{1000}{3*3.5*22.11}\) = 4.3:1.