Question about motor and generator size
Any electrical motor is also an electrical generator. The current flow and torque direction depends on the difference of the voltage applied and the mechanical speed applied from outside.

As the losses have to be supplied by the driving side, it depends whether you talk about electrical power or mechanical power.


If you talk about electrical power, the generator has to be slightly bigger, because the mechanical part has to supply all the electrical losses.
If you talk about mechanical power, the motor has to be slightly bigger, because the electrical part has to supply all the mechanical losses.