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POWER

POWER. Engines. During the industrial revolution, steam engines were used to run machines in a factory, to move trains and boats In a factory, the flywheel of the steam engine was connected by canvas belts to a shaft that ran the length of the factory, high overhead Reaction Engines

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POWER

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  1. POWER

  2. Engines • During the industrial revolution, steam engines were used to run machines in a factory, to move trains and boats • In a factory, the flywheel of the steam engine was connected by canvas belts to a shaft that ran the length of the factory, high overhead • Reaction Engines • Newton’s third law explains why reaction engines work --- jet & rocket engines • In a jet engine, the burnt mixture of air and fuel • Rocket engines carry their own oxygen supply • Nuclear Reactors • Large amounts of energy are released when large atomic nuclei are split • The reactor can move a ship and fulfill its electricity needs as well

  3. Engines • Electrical Motors • They change electrical energy into rotary motion • Small motors deliver less than one horsepower --- fractional horse power motors • They must carry their power source with them

  4. Transmission • They are used to carry force and motion from the engine of a power system to the object to be moved (the load) • Transmissions can be mechanical, hydraulic or electrical • Mechanical Power Transmission • Mechanical transmissions (sometimes called mechanisms) are very simple parts • Gears, pulleys, cams, levers, and linkages • Hydraulic Power Transmission • They transmit force through a tubing that carries the fluid • Pressure = force on a liquid/area • Pistons of different sizes can be used to obtain larger or smaller forces

  5. Transmission • Electrical Power Transmission • Alternating current, or ac is produced by generators at power plants • Electricity changed to heat by the resistance in the wires is lost • Transformers are used to change the voltage of the current • Transmission lines from several generating stations are often joined in a grid • Superconductivity holds promise for saving the loss of electricity in terms of heat • Superconductivity is possible in materials that were cooled nearly to absolute zero --- a temperature at which molecules stop moving --- about –459 F

  6. Continuous/Intermittent Power Systems • Continuous power systems are nearly always available, e.g. an internal combustion engine • Intermittent power systems sometimes store energy • Solar cells charge a battery when the sun shines • The battery in a car is recharged by a generator called a alternator

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