Electricity

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Electricity

• Transmission and Distribution

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Transformer

• A device that transfers electricity from one
  circuit to another

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Step-up Transformer

• A type of transformer that increase the voltage
  of electricity as it passes through

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Step Down Transformer

• A type of transformer that decreases the voltage
  of electricity as it passes through

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Transmission Voltages from Generator to Household

• 1. Electricity is generated at 12,500-25,000
  volts
• 2. Goes through step up transformer upped to
  138,000-765,000 volts
• 3. Carried through transmission lines

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Transmission Voltages from Generator to Household

• Substations use step down transformers to lower
  voltage to desired level depending on the usage.
• Distribution lines serving houses are usually
  12,000 volts
• Transformer on poles beside a house reduce the
  voltage down to 120 volts

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Transmission Voltages from Generator to Household

• 7. A typical house will have 2 legs of 120 volts
  for a total voltage in the house of 240

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Different Application use different voltages

• Pubic Transportation (subways, trolley cars) use
  600 volts
• Industrial Plants may use voltage as high as
  34,000 (they would have step down transformers
  inside the plant to further reduce the voltage)

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Review Questions

• Define Transformer
• Step Up Transformer
• Step Down Transformer
• Distribution Line
• Substation
• Transmission line

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• To increase voltage from 12,500 to 138,000 volts
  you would need a ____________.
• To decrease voltage from 7,500 to 120, you would
  need a ____________.
• The power lines that go cross country and are
  usually very high off of the ground are referred
  to as ___________________

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• The type of line that your house is connected to
  is a _______________.