4) Mechanical Advantage

The mechanical advantage of this oscillating fan is about 147. This is because there is a 44:1 gear ratio between the worm gear and the shaft, and a 40:12 gear ratio between the big gear and the gear connected to the worm gear. Multiplying these together yields a mechanical advantage of about 147. This relationship is observed when the fan oscillates much slower than the blades are spinning. The gear system causes an increase in torque and decrease in speed, allowing the fan to oscillate much slower than the blades turn. This is ideal so that the fan doesn't oscillate too fast. The motor can continue to operate at a speed fast enough to provide cool air to the user, while at the same time oscillating at a slow enough speed.