Abstract: An electrical propulsion system and control arrangements therefor, particularly advantageous for ship use, are disclosed. Power is supplied by an alternating current generator through rectifiers to two direct current motors each of which drives a propeller. The armatures of the motors and the rectifiers are connected in a series loop. The speed and direction of rotation of the motors are controlled by varying the motor fields. When the fields of the motors are reversed, for example for deceleration, regenerative energy fed through the propellers could cause excessive current to flow in the closed loop with resultant damage to the electrical apparatus. To prevent current above a predetermined maximum in this loop, a sensor responsive to current in the loop is provided and a signal from the sensor automatically controls the field of at least one of the motors to cause that motor to develop a back EMF preventing excessive flow of current in the loop.