Question

Explain how a gear system can be used to obtain gain in torque? Given one example.

Answer 1

A gear system can be used to obtain gain in torque when the smaller wheel drives the bigger wheel, i.e. when the driving gear has less number of teeth than the driven gear.
To obtain gain in torque, the gear ratio should be less than one. Mathematically

Gain in torque =`" 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡𝑒𝑒𝑡ℎ 𝑖𝑛 𝑑𝑟𝑖𝑣𝑒𝑛 𝑤ℎ𝑒𝑒𝑙"/"𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡𝑒𝑒𝑡ℎ 𝑖𝑛 𝑑𝑟𝑖𝑣𝑖𝑛𝑔 𝑤ℎ𝑒𝑒𝑙"`

Example: While ascending a hill, an automobile driver changes gears and puts the driving gear of less number of teeth with a driven gear of more number of teeth. By doing so, he obtains a gain in torque, as more torque is required to go up the hill than to move along a level road.