Question

what is the effect of using a big gear to drive a small gear in a robots drivetrain?
decreased torque and increased speed
increased torque and decreased speed
no change in speed or torque
decreased stability

Explanation:

When a big gear drives a small gear, the mechanical advantage comes into play. The big gear has more teeth. The torque - speed relationship in gears is inversely proportional. The formula for gear ratio \(G=\frac{N_1}{N_2}\) (where \(N_1\) is the number of teeth on the driving gear and \(N_2\) is the number of teeth on the driven gear). Torque ratio \(T_r = G\) and speed ratio \(S_r=\frac{1}{G}\). Since \(N_1>N_2\) (big gear driving small gear), \(G > 1\). So, torque is increased (\(T_r>1\)) and speed is decreased (\(S_r < 1\)).

Answer:

Increased torque and decreased speed