Electrical Machines Generalizations

8/6/2019 Electrical Machines Generalizations

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ELECTRICAL MACHINERYGENERALIZATIONS


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Rotating Electrical Machines:1. Generators

2. Motors

3. Rotary Converters

4. Frequency Converters


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Generator is a machine that

converts mechanical energy into

electrical energy.

Motor is a machine that converts

electrical energy into mechanicalenergy.


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When an electric generator is in operation, it

is driven (rotated) by a mechanical machineusually called prime mover.

Types of Prime Movers:

1. Internal combustion engines2. Electric motors

3. Turbines (steam, water, wind)

4. Reciprocating engines

5. Hand crank

6. Compressed air

7. Other sources of mechanical energy


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When an electric motor is inoperation, it is supplied with

electrical energy and develops

torque, that is, a tendency to producerotation. And if the rotating element

of the motor is free to turn, it will do

so and thereby cause mechanicalrotation of itself and its application.


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Motor-generator set


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Turbo-generator set


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Generators and Motors


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Wind-powered electric generator


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Wind-powered electric generator


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Solar Thermal Electricity


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The Parabolic Trough


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A parabolic through concentrates

sunlight onto a black pipe with

circulating water. This uses a

focusing mechanism like fresnel

lenses and fresnel mirrors.


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Thermal fluid expansion

converts the thermal energy

into physical energy to spin

an electric generator.


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The largest solar photo voltaic

cell in the world produces only

12MW but by comparison thelargest solar thermal plant in

the world generates 354 MW.


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There is at least 10 to 100 times

more money spent on solar

photo voltaic than what isspent on solar thermal which is

10 to 100 times more promising

for power plants.


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Gas Turbine Generator


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Combined Cycle Combustion Turbines


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The basic principle of CCCTs is to use

two complementary thermodynamic

cycles to efficiently generate electricity.

Heat generated by the combustion of

natural gas in a primary gas turbine is

used to create high pressure steam that

powers secondary steam turbines.


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These systems can have athermal efficiency of 60%. CCCTs

can be 40% more efficient than

older technology fossil fuel

generation and have 90% less

emissions.


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A natural gas/air mixture is burned

in the combustion gas turbine-

generator compressors creating

electricity. The hot combustedgases exit the gas turbine and enter

the Heat Recovery Steam Generator

(HRSG). The hot gases are used toconvert water into superheated

steam.


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High pressure steam generated by

HRSG is supplied to the steamturbines generating additional

electricity. Low pressure steam

exits the steam turbines to a coldwater condenser. This condensed

steam is used to recharge the HRSG,

again cycling to high pressure steamby the hot exhaust of the gas

turbine.


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Two thermodynamic cycles are

employed in combined cycle

combustion turbines, the BraytonCycle (gas turbine) which is combined

with the Rankine Cycle (steam

turbine)to create a very efficientmodern system of energy generation.


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Combined Cycle Combustion Turbines


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400MW

Gas Turbine Generator

Electrical Machines Generalizations

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