If One doesn't care about phase-frequency or voltage and need a high speed generator can current be fed to the rotor so that these motors can be used as a generator?One more question:What voltage is needed for the rotor? Say for example the120 volts single phase motor's normal running speed is 10,000, what voltage needs to be fed to the rotor so that if one is turning the motor at this speed it would generate around 120 Volts. I know there is a lot of problem with this set up but since its being converted to DC and used in a hydrogen production system, Voltage or frequency isn't a big issue.
Plug-in drills and vacuum cleaners have usually been universal motors, essentially the same thing as series connected DC motors. I don't believe they can be used as generators without changing the internal connections. The Dyson vacuums apparently use permanent magnet motors as do battery powered drills. Those motors would probably make good generators, but you would need to eliminate the electronic control and connect directly to the motor coils. Any motor that can be used as a generator would generate the rated voltage at the rated speed for which it was designed as a motor.
