Note that solid-state ceiling fan speed controllers will not necessarily work properly on a motor it was not designed for. Motors vary considerably in winding geometry, pole structure and load conditions. As such, speed controls need to be used on loads they are matched to in order to be effective. If you're fortunate, you'll get a sufficient range of control over the fan speed, but you may find you are limited to a small range of the control's sweep between the point at which the motor can start, and the maximum speed is attained. This, if it runs at all.

Does the motor have multiple-tapped armature windings, like many box fans? If so, you can adjust the speed by switching in and out different windings.