Generator/motor problems in pumped-storage installations

The paper investigates the problems in pumped-storage installations relative to the electrical ratings of the generator/motor units and the possibility of using two-speed synchronous machines for this duty. In those cases where the set runs in the opposite direction of rotation when pumping to that when generating, the paper discusses the problems arising in connection with starting the set on the pumping cycle, the design of the thrust bearing and the arrangement of the ventilating system. Frequent stopping is a characteristic of pumped-storage stations, and the paper shows that it is advisable to supplement the action of the friction brakes by a simple form of dynamic braking.