I would think that it would be better to have the switch go from the off position to the low position to the medium position to the high position, as why have it jolt to the high speed in order to go to the low or medium speed, right?
It’s even set up like that on my air-purifier – off, turbo, high, low.
I’ll let somebody smarter than me come in with a cite or a real answer, but I’ve always thought it’s set up that way so the fan gets a jolt at startup to get the blades spinning. If it started on low it may put unnecessary strain on the motor. Again, just a guess, but it makes sense to me.
I concur with this statement.
Another forum had covered the same question, which included an email response from a fan manufacturer rep.
The Hi setting is the fan motor at its native speed, the lower settings are achieved by applying geared braking to the motor.
This saves motor wear from starting the fan with the motor braking gear applied.