There's an interesting article over at OCAU regarding 3 phase power and just exactly what it is and how it works. Quite a good read if you've always wanted to know the basics about 3 phase power.
So what about three phase power? Pavarotti is big and expensive and a rather lumpy source of air pressure. Plus with modern technology we can use a more complicated scheme if there is a benefit to it. So instead of Pavarotti we get three choir boys with three small balloons. Two of the choir boys are blowing up their balloons while the third one has his connected to the hose intake. Then they switch off in a three phase sequence so that there is always a balloon connected to the hose intake.More information at OCAU