just thaught i would let everyone know how to controll the speed of any AC 230V fan
forget dimmers they dont work right coz they create rumble and burn your fans out.
go and do yourself a favour and get what is called a variac (variable transformer) maplin and rapid do them
there not cheep but they are the dogs bollocks. they will go from 0-240V with a dial
this will enable you to set your fan at any speed.
ooo and you will need something to house them in coz there open (electricity can kill)
ermm the link is ---
http://www.maplin.co.uk/Search.aspx?criter...6E&DOY=28m7