This video simply defines the working of an Electric motor as a generator. Here an exhaust fan which is a single phase induction motor has been converted to an electric generator simply with the theory of REVERSE PSYCHOLOGY. Check the video to see how to do it.
Note: You can use any fan or motor instead to do this.
Working: The slip of an induction motor=synchronous speed-rotor speed. If slip is negative the induction motor works as an alternator (AC GENERATOR). That's what we do here forcing the slip to go negative.