A little bit of info on what can control shaded pole and other general types of AC motors:
Solid-State Speed/Power Controler YES
Variable Hertz/Frequency Drive YES
Potentiometers, Dimmers and Rheostats can not be used to control the speed of an AC motor. They all use forms of voltage resistance.
From first hand experience I know that even low draw Hz drives can cost well over $100 (I have seen them as high as $500 at a 1 Hp rating). Hz drives are a waste unless you need to precisely control the speed/pulse of something beyond/below the input frequency (or a capacitor run/start motor). The next best thing is a solid-state adjustment device.
$10-$15 Solid-State Controler (I.e. fan controller)
$1.50 #16 (or bigger) extension type cord, with ground (2 feet)
80 3/8 cable connectors (x2)[/b]
$5 1 male & 1 female standard rubber 3-prong electrical plug
$3 Deep set 2x3 electrical box
All of this can be bought at an home improvement store for around the same price (such as Home Depot or Lowes).
Note: you need to have some basic wiring skills to do this.
The first thing you need to do is confirm your not buying a Rheostat or Dimmer. Look at the price and what\'s printed on it (fan controls are more expensive). You need to make sure it says it can control attic and/or whole house fans. I chose the 100% controllable one, they also make them with a Low/Med/High setting. The next part isnt much harder, basically all you do is strip your cable & wires and put on your plugs. In this case I already (knowingly) left some on the M/F ends from a previous project. Strip your cable and wires at the other end, then using the supplied wire nuts connect all commons (white wire) together. Connect one hot (black wire) to ether hot lead (black wire coming out of device). Now for the ground/s (green wire) use an extra wire nut. Or you can strip about 2 off all of them and twist them together nice and tight (if you don\'t have a wire nut). Next push the fan controller into the box, before doing so tuck the cluster of grounds under the other wires. There should also be 2 supplied machine screws that you will use to attach the mounting plate to the box.
Thats all there is too it, it can be used just like a regular fan (only now you can adjust the CFMsspeed).
Notes: Dont load it to max capacity. In this case using the 5 amp model dont use it to control a fan/motor the uses more than 4 - 4.5 amps. These CAN NOT control capacitor start or run motors (you would need a Hz drive for that.). When used, the motor will get warm/warm-hot as if it where running regularly, this is normal. Another thing I would do is let the motor run for at least 3 hours (check on it from time to time) on the lowest setting just to make sure it wont over heat.