Electromagnets, Motors and Generators 6.4 Flashcards
What are Permanent Magnets?
-Have an invisible force called a Magnetic Field
What are Magnetic Fields?
-Act on other magnetic materials, containing iron, cobalt and nickel
-Strength can be represented by field lines
What is Electromagnetism?
-An electric current produces a magnetic field
-Current moves along wire, generates circular magnetic force
-Wire wrapped to form a coil, strength of magnetic field increased, strongest at center of coil
What is a Solenoid?
-Coil of wire with electricity flowing through
What are Electromagnets?
-Iron rod or magnetic material placed in center of coil, magnetic field becomes stronger
What are the advantages of Electromagnets compare to normal magnets?
-Can be on or off depending if there’s current flowing through
-Strength can be altered by changing its current
-Direction of magnetic field can be changed by changing direction of current passing through
What are Electric Motors?
-Convert electrical energy to kinetic energy
-Made by placing a solenoid on a swivel between a permanent magnet
-Works by magnetic field of solenoid interacts with magnetic field of magnet, this repulsing/attraction causes solenoid to spin
-Kinetic energy used to turn wheels, spin fans, etc
What are Generators?
-Use kinetic energy to produce electrical energy
-Done by manually spinning the magnet or solenoid
-Turbines use water or steam as spinning force
What are Turbines?
-Need to be spun at high speeds
-large generators spin their magnets, keep their solenoid fixed
What are Ways to Spin Turbines?
-MOVING WATER
*Hydro-electricity: Water flows down spins turbine, e.g. Snowy River
*Waves: Regular swells move turbines
*Tide: Regular patterns of tides move water over turbines
-STEAM
Water heated, turned into high pressure steam that turns the turbine, steam exit via cooling towers.
Water can be heated via:
*Burning fossil fuels(gas/coal)
*Burning organic matter(wood)
*Geothermal energy(heat from deep Earth)
*Nuclear power
*Solar power
What are Dynamos?
-Generators power lights of bicycles
-Works by small magnets spun around a solenoid
What Produces Alternate and Direct Current?
-Batteries and solar cells produce direct current(DC)
-Generators, dynamos and turbines produce alternating current(AC)
What is the Transmission of Electricity?
-Power plants produce electricity at 20,000V
-Electricity must be transmitted from power plants to homes/business
-Long wires have a resistance in electricty transport creates wasted energy
-Power lines can be so dangerous, transformers increase voltage to 220,000 to 500,000 solely for transmission
-Transformers at the other end reduce voltage to 240V for house wiring
