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 Aluminum-Used Primarily on -Used primarily on the customer side the utility side of of the meter. the meter.-A better conductor -Not as good a
than aluminum. conductor as copper.-More expensive. -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