If the drive sheave size is doubled, how will the speed of the fan change?

When the drive sheave size is doubled, the speed of the fan will also double. This occurs due to the relationship between the drive sheave size and the rotational speed. The drive sheave, which is part of the pulley system, controls how much rotation is transmitted to the fan.

When you increase the size of the drive sheave, the fan's ability to receive power and rotate faster increases as well. The fundamental principle at play here is that the speed of the fan is directly proportional to the size of the drive sheave: as the sheave size increases, the fan must compensate by increasing its speed to maintain the same ratio of motor to fan speeds.

In contrast, other options suggest different relationships that do not align with this mechanical principle. Tripling the speed would imply a much more significant increase in sheave size or a change in other parameters, while stating that the speed remains the same or is halved contradicts the direct relationship established by doubling the sheave size. Therefore, doubling the drive sheave directly results in a doubling of the fan speed.