Can I Use A Motor From a Fan For Electricity

disconnect the fan from whatever it is currently hooked up to there should be 2 or 3 wires. if its 3 hopefully 1 is black and another is red. hook your meter up to these. use a fan to blow on this fan.
now 2 things you should look for, first is does the fan you're using rotate the fan you are trying to make a generator out of? and second is there even the smallest movement in volts?
this will tell you if you can do what you're hoping to do

 

There are many kinds of motors. Some will generate, others will not. If a motor is to generate, it will need to contain a permanent magnet. This can be discoverd by holding a needle on a thread and see if it is pulled towards the motor. Also, most permanent magnet motors when turned will seem lumpy. This is known as cogging and is due to the rotor passing the magnet. A 12V motor for driving fans in a car would be a good example of this type.

Another common type of fan uses a shaded pole motor, this runs on AC and will not produce power. These motors are usually of open construction with the coil to one side, the pole pieces are 'shaded' with a copper ring around half of the pole piece. They spin very easily without cogging.