Question

2. At its rated speed of 2000 rpm, a 2WD two drive tractor engine develops a rated torque of 200 Nm. The transmission to the wheels at the rear of the tractor has a mechanical efficiency of 90%, and each drive wheel has a diameter of 1.2 m. If the tractor is operating in a gear which gives an overall transmission ratio of 80:1, what is the gross tractive thrust F at the tractor wheels?

Hints: The method for calculating the gross tractive thrust F of the tractor is shown in the worked example Question 4, Module 4, in the studybook. Please note that the torque at the wheel will not be equal to the engine torque divided by the transmission ratio 80. As a mechanical loss will occur in the transmission system, you will have to take this into account in the calculations. The torque at the wheel will also be equal to F multiplied by wheel radius.

(40 marks)

Answer 1