does a 3 phase ac electric motor used as a generator create 3 phase ac power?
No, only if you provide a source of 3 phase power to energize the field windings. Without that, you just have a few coils of wire spinning near other coils of wire. No magnetic fields, no power generated.
Yes, it generates 3-phase power. To create the magnetic field that transfers energy from the rotating shaft to the stator coils, it needs either: 1. Permanent magnets (no excitation required, synchronous generator) 2. A dc exciter (think of it as using electromagnets in place of the permanent magnets) 3. 3-phase power applied to the output. When the prime mover spins the shaft faster than synchronous speed, the device acts as a generator. When the prime mover tries to slow below synchronous speed, the device acts as a motor. This is an induction generator. It can't work as a stand-alone generator. It has to connect to the grid or to a power source (such as another synchronous generator) that can provide reactive support. You can also use a 3-phase motor to convert 1-phase to 3-phase. You apply single phase to two of the output terminals. The trick is that you have to manually start the motor spinning, or use a timer to temporarily connect a capacitor. It will then come up to speed on its own. It will generate the missing phase. You can connect a three-phase load to the three terminals (with proper protection, of course). Look up static phase converter for more information.
