the poles are fed, alternating current generators can produce a variable number of phases of power. A higher number of phases leads to more efficient power system operation but also increases the infrastructure requirements of the system. Electricity grid systems connect multiple generators operating at the same frequency: the most common being three-phase at 50 or 60 Hz.

There are a range of design considerations for power supplies. These range from the obvious: How much power should the generator be able to supply? What is an