[jacquesm]

Electric motors and alternators are mostly equivalent, the difference is that the diode assembly on a car alternator would stop you from using one as a motor. Otherwise, they are roughly identical.

That you don't find a 'traditional' alternator in an electric or hybrid car is simply because the electric motor doubles in that role when required.

Almost all electric motors when spun will generate power, you'd have to do some work to get one not to generate power when driven.

[m4x]

AC induction motors are the most common type of motor for anything other than small electronics and turning one by hand will not generate any output power. They are definitely not identical to an alternator. The armature of an induction motor doesn't have an associated magnetic field so turning it won't generate any power in the windings.

Permanent magnet motors are the only motor that will generate power if you just pick one up and turn it by hand, and they are quite rare (and expensive) at scales larger than a RC toy motor

[jacquesm]

Sorry, but you're wrong there. Remanent magnetism will allow you to use an AC induction motor as a generator just fine.

Absent any remaining magnetism you can 'flash' the motor core with a short DC pulse and then start rotating it with your chosen driver afterwards.

Just one sample (of many) of people using this trick for all kinds of interesting small RE applications:

http://www.smallhydropower.com/induction.htm

[m4x]

Interesting reading, thanks. There is always somebody with another clever trick up their sleeve.