An electric motor with two independent output shafts connected to the rotor by coupling means working in one sense of rotation only, e.g. by means of freewheel clutches. The first freewheel works in one sense of rotation while the second freewheel works in the opposite sense. Two operating devices can be powered by the motor, simply by switching the sense of rotation; an example of use is a combined pump-compressor machine. Various embodiments are disclosed, some of them obtainable as a simple and low-cost modification of an existing motor or motor-pump assembly.