Electric motor control in submarines
 

I have a very technical question for all real (or armchair) Machinist and/or Electrician Mates over here. The question is: How electric motor power output was adjusted on a WW2 diesel -electric submarine?

Because in electric locomotives, for example, the motor RPM is controlled by means of connecting and disconecting resistors from the motor's circuit
I first thought it is the same on a submarine, but then i realized that those resistors on a locomotive are cooled either by airflow at speed or powerful fans and i seen neither of those on any submarine. So how was it done ?

I'm certainly not an electrician of any kind, and have no clue.

You might, however, find some answers here.

And if not, that might keep you entertained anyway. :sunny: