AC Fan Wiring without knowing connection
Because there are only two wires with terminals at the end I am assuming it is single phase. If this is the cause, it doesn't matter how you hook up which wire goes to positive and which goes to ground. It will work fine either way. 

If this is a 3 phase motor (I don't think it is) you can tell which phase is which by the amount of resistance between the wires. 

As far as the capacitor you usually see on motors, that is to help with in rush current. The capacitor can be charged before hand and when the motor is starting the capacitor can help supply current so the motor doesn't draw as much current on start up.