Electromagnetic Machines
For the most basic of all hydroelectric dams, the idea is to build a dam on a river that has a large drop in elevation. At the top of the damn there is a reservoir and at the bottom of the wall there is intake. Gravity forces water down the wall into the intake and through a penstock (a large hollowed out pipe). At the end of the penstock there is a large turbine propeller that is spun by the rushing water. A shaft is attached to the turbine that spins with the turbine and the shaft is connected to a generator which creates the power. The water then flows out into an outflow lake where it waits to be pumped back into the reservoir at night/early morning with the excess power for the next day of use (U.S. Department of the Interior, 2005).
The way hydroelectric power plants generate electricity is within accordance with the first law of thermodynamics that states energy cannot be created or destroyed, only distributed from one form to another. For the plants to generate electricity the water must be in motion (kinetic energy), when it reaches the turbine most of this kinetic energy is converted into mechanical energy (the spinning of the shaft).
Hydro electric generators can vary quite largely throughout each power plant; however each generator uses the spinning shaft that is connected to the turbine. The shaft spins a large magnet (rotor) at high, fixed speeds around coils of a conductor (stator) which according to Faraday’s Law of Electromagnetic Induction will create a current inside the coiled wire that can be harvested (Perlman, 2014). The electricity is then directed through a transformer across long cables of transmission lines where it becomes available for commercial use.
Hydroelectric Dams
Electromagnetic induction, or otherwise known as just ‘induction’, is a process where a conductor is placed in a changing magnetic field or a conductor is moving through a fixed magnetic field. This causes the creation of voltage across the conductor, thus causing an electrical current (Jones, 2014). Electromagnetic induction also work is reverse so that a moving electrical charge can generate a magnetic field.
Hydroelectric Dam Components
The different vital components that a hydroelectric dam consists of are:
Water – The water is the most vital component of the hydroelectric dam’s source because obviously without the potential energy of the water rushing through the penstock there would be no power generated.
Turbine – The turbine is part of the mechanical machinery. It is the blades that are pushed by the force of the water. They are connected to a mechanical shaft that is spun around at a fixed speed.
Dam – The dam wall is what contains the water in a reservoir. This stored water is what’s used to spin the turbine, and thus, in turn create the power.
Generator – The generator itself consists of two main parts:
Rotor – The rotor is a rotating magnetic spun by the shaft. This rotor turns at high fixed speeds around coils of a conductor and induce a current on them.
Stator – The stator is the coils of conductor. The rotor rotates around them and the electrons inside the conductor have a current induced on them by the magnet, within accordance to Faradays law.
(U.S. Department of the Interior, 2005)
(U.S. Department of the Interior, 2005)