A 60 Hz system is a lot more efficient than a 50 Hz system, hence extra heating is an issue in a motor designed for 60 Hz running on 50 Hz.
The 60 hz motor will have generally less iron, because of the better efficiency.
A possibility is to use a 230 / 92 Volts transformer,
( 110 * 5/6 = 92.5 )
The fan speed will be less, 5/6 of the normal running speed.
The starting torque will also be reduced and it will take longer for the fan to get up to speed.
Otherwise get a European fan as already suggested.
