Do household AC motors (mixer, vacuum cleaner, etc) work as electricity generators if used in reverse?
Only if the motor is a permanent magnet type motor. Most motors are electromagnetic, having electromagnets that operate only when A/C current flows through the coils of the field. If no current flows through the motor's field windings, then there is no magnetic field to pass, or rotate the stator through, so it will not create energy. When current flows through the fields, the motor is only a motor. On permanent magnet motors the magnets do not need to have current to work, so when the stator passes through the magnetic field, such as in a wind turbine, it creates energy.
No. a generator requires 'excitation current' to the coils or permanent magnets. You have to have a magnetic field. Just spinning an AC motor won't work. If a wind turbine is your goal, and you're 'lost' in things electrical, an automotive alternator with it's regulator and battery is the way to go. A relatively cheap inverter will give you the 120V. AC . All the electrcial engineering is already done for you, and all you've got to do is spin it at about 1500 - 2000 RPM.
AC motors would require some internal rewiring to act as generators. The short answer is No
Only if they have brushes in them (motors that will work on a.c. or d.c.). They don't have to necessarily be used in reverse, either - they'd generate when turned in either direction (at reversed voltage in the case of brushed motors). However, you're talking alternative energy systems here, and motors with brushes don't hold up in long-term, 24/7 service. I have used industrial quality 3-phase motors as generators, instead. Those motors are available dirt cheap if you buy them used, and even new they're not especially expensive. You need to add 3 capacitors to them to make them generate, and they generate at 3 phase 240 volts. You could mount your unit up to several miles from your house and still be able to economically send the current over 3 wires of #10 wire in many cases. 3 transformers are used at the house end to convert back to battery bank voltage where they power an inverter, at least in my systems. Write me privately if you'd like the circuit for this. EDIT: To the thumbs down posters, I have used one of these 3-phase motors-as-generators to power an off-grid house for 3 years now (connected to a waterwheel with a 1-100 gear increaser). The capacitors I add to the circuit supply the excitation current. The schematic is free for anyone that asks. I don't know why you would give this a thumbs down, this makes a very efficient generator.
