How Kentucky Dam Works
Power to run the generators at hydroelectric dams is provided by the force
of water spinning huge turbine blades which are connected to the generators.
In this cross section one can see magnets turning inside the coils of wire
to produce the electricity which lights home and street lights.
Connected to the base of the generators are vertical shafts which extend below the powerhouse floor to the turbines. To generate electricity, water enters the dam through the penstock, or pipe, which leads to the power house structure. There the force of the moving water turns the blades of the turbine. The turbine shaft is connected to the generator that produces electricity. Once it's work has been accomplished, the water is returned to the river through the draft tube underneath the powerhouse. Navigation and flood control were the primary goals of Kentucky Dam's designers. The turbine bay was to contain "roughed in" stalls for the generators. With the outbreak of World War II, the demand for electricity increased and four generating units were installed during construction. The fifth unit was installed four years later. Each turbine assembly weighs 487,500 pounds or more than 220 tons.
Imagine this 102 ton carbon-steel turbine spinning at 78.3 revolutions per minute. Picture more than 78,500 gallons of water per second rushing through the intake to spin its heavy blades which generate 37 mega-watts of electricity. Measuring over 21 feet wide and nearly 12 feet tall, this adjustable-blade Kaplan propeller-type turbine, the first to be installed at Kentucky Dam, began commercial operation in 1944. Although it's huge, it plays only a small role in TVA's balanced river system.