There are many forms of using electric motors to make generators. Examples are as follows:
1. The motor used for fans can be converted into a generator. You can dismantle the rotor, carefully remove the aluminum bars in the rotor and the aluminum short-circuit rings at both ends, and add the field winding. Add slip rings, carbon brushes and excitation circuits in series. This method is troublesome to operate, but the output voltage can be adjusted by adjusting the magnetism.
2. Using an AC motor as a generator is called an AC asynchronous generator. The matching and use method is very simple. Just connect a capacitor of appropriate capacity to the lead of an ordinary asynchronous motor, use a diesel engine or other power to drive the motor, and the motor will become a generator. The synchronization of the motor The speed is the rated speed used as a generator; total capacitance selection: on motors above one kilowatt, choose a triangle connection capacitor, which can be 10μf (microfarads) per KW, and a star connection of 17μf (microfarads). The capacitor's AC voltage resistance must reach or exceed 400V before it can be used. The efficiency of this asynchronous generator is maximum 80% of the original electric motor power.
3. Directly replace the original rotor with one or two pole permanent magnets. The magnetic poles of the permanent magnets should be as close as possible to the stator, but not in contact. By rotating the rotor (or permanent magnet rotor), voltage and current can be output through the stator. If you increase the speed, the voltage can be raised to a very high level.
4. Generators and electric motors have different functions, so their design and manufacturing are also different. Even if an ordinary electric motor is converted into a generator, it will be "successful" and its efficiency will be very low.