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Electricity Merit Badge Class 3 – Electric Power We Use Alternating Current (AC)

Electricity Merit Badge Class 3 – Electric Power We Use Alternating Current (AC) Safety & Conservation. Classes. Class 1 – Basics Electricity (shared with the Electronics Merit Badge) Class 2 – Magnetism Class 3 – Electric Power, Alternating Current Generating electricity

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Electricity Merit Badge Class 3 – Electric Power We Use Alternating Current (AC)

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  1. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Electricity Merit Badge Class 3 – Electric Power We Use Alternating Current (AC) Safety & Conservation

  2. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Classes • Class 1 – Basics Electricity (shared with the Electronics Merit Badge) • Class 2 – Magnetism • Class 3 – Electric Power, Alternating Current • Generating electricity • Step up and step down voltages • Safety devices • Conservation • Class 4 – Safety at Home

  3. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree The Electricity We Use – a Quiz Where does the electricity come from to power these?

  4. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree DC – Mostly Batteries • DC means “Direct Current” • It doesn't change much • Hook a battery to a meter or a bulb • See, it doesn't change much

  5. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree AC – What Comes Out of The Wall • AC means “Alternating Current” • It's what comes out of the wall outlets • It “alternates” from high to zero to low to zero to high... and on and on • It alternates very fast + Direction - Direction

  6. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Generating AC • Spin magnet near coil • See energy go from zero to high to zero to low • Spin speed is the “frequency” • At home it's 60 cycles per second

  7. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Power Plants Generate Electricity • Electric company power plants work the same way • Spin magnets in front of three coils • Uses steam turbine or wind or water to spin • Coils “make” electricity that’s sent to your home

  8. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree How to Spin a Generator • Steam Turbine • Spins because steam pressure presses against turbine blades • Spinning turbine spins a generator • Used more than any other form of generation

  9. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Steam from ... Coal Nuclear Natural Gas

  10. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Very Old & Very New Forms of Generation • Hydroelectric, falling water • Wind where it is windy • Solar where there is much sun

  11. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Getting the Power to the Consumers • Power generation plant to… • High Voltage transmission lines to… • Substation to … • Distribution lines to … • A house or business 125,000 to 750,000 volts 25,000 volts 7,500 to 35,000 volts 120 & 240 volts

  12. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Why Change Voltages? • Power company sends 120,000 watts to a shopping center • At 120 volts that’s: • 1,000 amps • BIG wires • BIG pole to hold the BIG wires • At 125,000 volts that’s: • 1 amp • small wires • little pole to hold the little wires

  13. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Remember Power Formula? • P (watts) = I (amps) x E (volts) so • I (amps) = P (watts) / E (volts) I = 120,000 watts / 120 volts so I = 1,000 amps I = 120,000 watts / 125,000 volts so I = .96 amps

  14. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree But Not High Voltages Everywhere • Very high voltages near people are dangerous • Voltages are reduced closer to people and buildings • That’s what you see here 125,000 to 750,000 volts 25,000 volts 7,500 to 35,000 volts 120 & 240 volts

  15. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Voltage Changed by a Transformer • Primary coil (windings) is input • Secondary coil (windings) is output • Step-up or Step-down • Ratio of windings determines up or down voltage

  16. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Transforming Power • With AC, transformers change the voltage up and down • Step up transformers increase the voltage (electrical pressure) so power companies can use smaller wires to carry the current (energy) • Wires on the poles or underground near your house carry 7,000 to 35,000 volts • Step down transformers reduce it to 240 volts (for your stove and A/C) and 120 volts (for your lights, TV, etc.)

  17. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Where Transformers are Found

  18. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree What Transformers Look Like

  19. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree What Happens When Power Lines Go Bad

  20. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Preventing Power Accidents • Too much current (amps) on the line trips: • Big circuit breakers in substations • Fuses on poles • Fuses in transformer cabinets • That turns off power in the lines

  21. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree How You Can Prevent Power Accidents • Why are these dangerous?

  22. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree What Happens When You Touch a Power Line

  23. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Keep Safe Around Power linesAbove You and Under You Don’t let anything get near the electric wires Call 811 before you dig to have underground wires marked

  24. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Marked Underground Power Line • This man called 811 for marking • Red stripes mark the underground line • Dig at least 2 feet away from marked line

  25. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Conservation – Saving Energy Measuring the Electricity Used Read meter from left to right Notice some numbers go clock-wise, some go counter clock-wise Read two months, subtract to find kilowatt hours used

  26. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Calculating Consumption • If last month was 14840 • And this month is 15964 • Then 15964 – 14840 = 1124 kilowatts-hours used • At $0.10 per kilowatt = $112.40 • Reduce the kilowatt-hours used and you reduce the cost

  27. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Reducing the Power You Use • How much power do these use? • How is a lumen different from a watt?

  28. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Finding Lower Powered Stuff • More power consumed means more coal burned, more natural gas burned, more nuclear fuel used • EnergyStar label on an appliance means it uses less power than others • Check the label for power usage

  29. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Give 5 Ways Your Family Can Conserve Energy

  30. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree Reducing Power on the Small • LED flashlights save batteries • Fewer batteries means less in land-fills

  31. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree What We Learned • AC means alternating current • AC is what we use in our homes for lights, etc. • Spinning magnets near coils of wire is how power companies make most of the electricity • Transformers step up and step down voltage for efficiency • Electricity can burn and cause fires if not handled properly • Circuit breakers and fuses prevent fire

  32. Electricity Merit Badge Class 3 - 2013 National Scout Jamboree What We Learned • Stay away from power lines above and below you • New bulbs can save electricity • Lumens measure amount of light • Watts measure the power consumed • EnergyStar means less power consumed • LED means Light Emitting Diode • LED flashlights use less power so batteries last longer

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