Unless I messed up my research I believe you can use one of these on capacitor start motors.

http://www.solutionsforair.com/produ...emnumber=1DGV3

Here is the manual. In the manual it says it can be used with a PSC motor which is a permanent split capacitor motor, also known as a capacitor start motor.

http://www.solutionsforair.com/dayto...edControls.pdf

Hopefully I'm correct or I just bought and installed a $64 paper weight.