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Agricultural Electricity What is Electricity? • Easier to describe what it does than what it is! • The flow/movement of electrons through a material. Direct Current (DC) • Flow of electrons in only one direction. • Produced by: • • • • DC Generators Batteries Solar (PV) Cells Wind Turbines Alternating Current (AC) • Flow of electrons in one direction and then the other. • Produced by AC generators. • Supplied by Modern Power Suppliers. How do they flow? • Conductors • Materials that allow electrons to readily move from one atom to another. • Most metals are good conductors. (silver, copper, gold, aluminum) • What about water? • Distilled water? Copper vs. Aluminum Copper -Used Primarily on the customer side of the meter. -A better conductor than aluminum. -More expensive. Aluminum -Used primarily on the utility side of the meter. -Not as good a conductor as copper. -Less expensive. -Lighter. Insulators • Materials that do not allow their electrons to readily move from atom to atom. • Rubber, plastic, glass, porcelain, ceramics. Voltage (Volts) • The pressure/force pushing the electrons through the material. • Similar to water pressure in a water piping system. • Supplied by the generator. • Symbol= E or V Kilovolt (kV) • 1000 volts • Used to define the voltages of transmission lines and higher voltage distribution lines. • Examples: • 345 kV line=345,000 volts • 12.5 kV line=12,500 volts Current (Amps) • The rate of flow of the electrons through the material. • Similar to the flow rate (gallons/minute) in a water pipe. • One Ampere=6,280,000,000,000,000,000 electrons per second • Byproducts • Heat • Magnetic Fields •Symbol=I or A Resistance (Ohms) • Measure of a materials impedance/resistance to the flow of electricity through it. • Similar to the friction/head loss in a water piping system. • Symbol= omega Resistance Creates Voltage Drop • Voltage drops on a circuit the farther you get from the source. • Low voltage can cause: • Dim lights • Hot motors • Reduced motor life Real Power (Wattage..Watts) • A measure of the power used by an appliance. • “The rate or ability to do work” • Symbol: W Kilowatts • 1000 Watts • Most power suppliers use kilowatts to quantify how much power commercial/industrial customers use for billing purposes. • Symbol=kW Megawatts • 1,000,000 watts • Commonly used by electrial people to measure the power a generator is capable of producing or the power requirements of large customers or cities. • Symbol=MW Ohm’s Law • The basic physical law describing how electricity acts. • Volts=Amps X Ohms • Helps us figure out “How big should the wires be?” Why can’t I run my coffee pot, toaster, blender & microwave without the breaker tripping? • How many amps does a circuit with a 1000 watt coffee maker, a 500 watt toaster, a 200 watt blender and a 700 watt microwave draw when all operate? Use Watt’s Law • 700+1000+500+200=2400 Watts • Watts=Volts X Amps • 2400 Watts divided by 120 volts=20 amps Practice • On a 120 volt system how many amps will a 800 watt microwave, 1000 watt coffee maker, a 500 watt toaster and a 200 watt radio. • Watts= volts x amps Long-Nose Pliers Diagonal-Cutting Pliers Crimper Multipurpose Tool Wire Strippers Cable Ripper Lineman’s pliers Automatic wire strippers MultiMeter Amp Meter