You are a designer and have been asked to create a prototype of an electric fan that spins at least 300 rpm. Your materials for the prototype include an electric motor that spins at 150 rpm and a variety of gear sizes. Describe a gear train that you might create to meet the requirement.
To increase the speed of the electric motor to 300 rpm, we can design a gear train using two sets of gears: a larger gear attached to the electric motor shaft and a smaller gear attached to the fan blades.
First, attach a gear with a larger circumference to the electric motor shaft. This gear will spin at 150 rpm, the same speed as the motor. Let's say the larger gear has 12 teeth.
Next, attach a smaller gear with fewer teeth to the fan blades. To increase the speed to 300 rpm, we need to double the speed, so we can attach a gear with 6 teeth to the fan blades.
By connecting the two gears together in a gear train, the larger gear will turn the smaller gear twice for every rotation, effectively doubling the speed from 150 rpm to 300 rpm.
This gear train design will allow the electric fan to spin at least 300 rpm while using the existing 150 rpm electric motor.