Double Revolving field theory-how the rotor develops torque
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interduction to electrical power systems
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8. Suited for high head, low flow sites.
The largest units can be up to 200 MW.
Can operate with heads as small as 15 meters
and as high as 1,800 meters.
Pelton Wheels
9. โข Combined action of pressure and moving
water.
โข Runner placed directly in the water stream
flowing over the blades rather than striking each
individually.
โขL ower head and higher flows than compared
with the impulse turbines.
Reaction Turbines
10. The inlet is a scroll-shaped tube that wraps
around the turbine's wicket gate.
Water is directed tangentially, through the
wicket gate, and spirals on to a propeller
shaped runner, causing it to spin.
The outlet is a specially shaped draft tube that
helps decelerate the water and recover kinetic
energy
Kaplan Turbine
11. The inlet is spiral shaped.
Guide vanes direct the water tangentially to the
runner.
This radial flow acts on the runner vanes,
causing the runner to spin.
The guide vanes (or wicket gate) may be
adjustable to allow efficient turbine operation
for a range of water flow conditions.
Francis Turbines
28. โข 235U fissions by absorbing a neutron and producing 2 to 3 neutrons, which
initiate on average one more fission to make a controlled chain reaction
โขNormal water is used as a moderator to slow the neutrons since slow
neutrons take longer to pass by a U nucleus and have more time to be
absorbed
โขThe protons in the hydrogen in the water have the same mass as the neutron
and stop them by a billiard ball effect
โขThe extra neutrons are taken up by protons to form deuterons
โข235U is enriched from its 0.7% in nature to about 3% to produce the reaction,
and is contained in rods in the water
โขBoron control rods are inserted to absorb neutrons when it is time to shut
down the reactor
โขThe hot water is boiled or sent through a heat exchanger to produce steam.
The steam then powers turbines.
Nuclear Reactor works
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32. Nucleons more tightly bound in Fission Product Nuclei โ Gives
200 Mv Energy per Fission
