Presentation on theme: "Chapter 11 Magnetism Electrical Generation Electrical Transmission Environmental Impacts of High Voltage Lines Standard Power Generation Cogeneration and."— Presentation transcript:
Chapter 11 Magnetism Electrical Generation Electrical Transmission Environmental Impacts of High Voltage Lines Standard Power Generation Cogeneration and Combined Cycle Plants
Energy in the News
Magnets Lodestone or magnetite- first recognized by the Greeks in 500 BC. Used to make a compass needle. Like charges repel. Unlike charges repel. Magnetite= Fe 3 O 4
Earths’ Magnetic Field Lines
Magnetic Particles Lined Up in Field Dark: Elongated Magnetic Particles Pyrotite? Light: Radiolarian Skeletons What direction Are the Field lines?
Electrical Currents Make Magnetic Fields Wire carrying current affects a compass needle: Original experiment by Oersted that discovered magnetic fields produced by electrical currents.
Coils of Wire (Solenoids)
Parallel Currents Attract
Parallel Currents in Loops Attract
Parts of an Electric Motor Simple Electric Motor Outside: Field magnet (permanent Magnet) Inside: Rotating Electromagnet Reverses its field every half rotation
Detail of Electromagnet in Motor Electromagnet is connected to A battery or other power source Armature (green) allows the current Direction to switch every 180 Degree rotation, thus switching The North and south poles of The Electromagnet
Two Types of Current Direct Current (DC): constant intensity and sign Alternating Current(AC): varying intensity and sign Some devices generate direct current, some Generate alternating current.
A Moving Magnet Produces Current in the Wire
Electrical Generator What type of current is made by this generator? What could turn the generator?
Electrical Generator: Second View Wire is turned In the magnetic Field Result: Current In the wire.
Alternating Current from Generator
Cross Section of Gas Turbine Gas turns blades on left: Right side connected to generator
High Voltage Transmission Lines Typical Voltage: 345,000 Volts Why are the voltages So high?
Transformer: Changes Voltage and Current (not Power) Two coils with alterating Current. First coil induces A current in the second coil. Difference in voltage Proportional to difference in Number of windings of Wire. V in * I in = V out * I out
Transformer on Power Pole Why is the voltage stepped Down at the last minute, just Before power is sent into The house?
Overall Electrical Distribution
Typical Magnetic and Electrical Fields High voltage transmission lines: exposure MIGHT correlate With leukemia and brain cancer. Studies very contradictory.
Costs of Electricity
Costs of Transmitting Energy Transmission lines: most expensive way to move energy Moving energy in gas pipelines, by barge or by rail is much Cheaper. ( cost is about half). Why?
Turbines (Jet Engines)
How a Turbine Engine Works Air Enters On Right.. Shaft is Turned to Generate Electricity On Left.
Detail of Turbine Combustion Area
Cogeneration Power Plant= Both Heat and Power Output
Separate Power and Heat Generation vs Cogeneration