To obtain the gear ratio, TV = (output rate)/(input rate), of a compound gear train, an illustrated example is presented in this section.
The procedure is to start with the input, and to calculate how the angular velocity propagates through each successive intermeshing pair of gears based upon the number of teeth.
Consider a compound gear train below.
Suppose that the input gear speed (rotation rate) is 1600 rpm clockwise, i.e.,
The gear ratio between w_{1} and W_{2} is inversely proportional to the teeth numbers, n, i.e.,
Hence,
where the negative sign represents for counterclockwise direction.
Similarly,
and
The final gear ratio TV can thus be obtained,
