6gears and power transmission basics
Why do we need gears? An intuitive answer is that we need them to transfer drive from a motor to a receiving mechanism. While true, this is not the complete picture. The essential purpose of gears is to transform the properties of a power input to suit our purposes. Transferring drive is just a side effect of this process.
Gears can be driven by all kinds of inputs, from electric motors and manual cranks to wind turbines and mill wheels. Let’s start by considering gears powered by electric motors, because unlike other power inputs, motors have constant, measurable properties.
Every motor has a certain mechanical power, consisting of two factors: rotational speed and torque. These are the two properties we ...