Magnetism Not Magic

Generating electricity isn't magic. You can do it simply by passing a wire through a magnetic field.

A simple electromagnet contains a magnet and wire coils separated by a small gap. As you turn the crank, the magnet spins near the coils, producing electricity.

A generator is a machine that produces electricity. Hoover Dam's generators work on the same principles as an electromagnet. Each generator, though, has a turbine, rather than a crank. Water striking the turbine causes the spinning that produces electricity. Imagine how much water power it takes to spin a turbine, shaft, and rotor with a combined weight of over 600 tons!

High, Medium and Low Head Dams

Dams are categorized according to head, or the difference between the height of the water in the reservoir (forebay) and the level of the water downstream of the dam (tailrace).

The bigger the difference, the greater the water pressure to spin the generators' turbines. Dams are said to be “high head,” “medium head,” or “low head.”

Hoover Dam, with a head of over 500 feet, is a medium head dam.

Intakes, Penstocks, and Generators

Water enters the intake towers from Lake Mead.

Four 30-foot diameter pipes (penstocks) carry water from the intake towers to the generators.

Water is forced through narrower penstocks, increasing its velocity, and thus its capacity to turn the turbines.

Turbines power the 17 power plant generators to create electricity.

The Power Grid

The network of transmission lines and substations that transmit electricity is known as “the grid.” The grid extends across state boundaries so that the power system across the continental United States is linked.

Switchyards
Switchyards are power distribution centers where electricity is routed across the grid. Voltage levels are altered for efficient transmission. Switchyards may contain stepup or stepdown transformers.

Dispatch Centers
Dispatch centers receive information from all over the grid and use it to monitor and control power transmission.