power train components mjh
Post on 08-Apr-2018
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Power Train ComponentsPower Train Components
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IntroductionIntroduction Reduction Gears - fast to slow
Lubrication System - overcome friction Shaft components - turbines to the working
medium (ocean)
Propeller - transform rotational energy intothrust
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Reduction GearsReduction Gears Purposes
Allow turbine andpropeller to operateat most efficientspeeds
Combine twoturbines to commonshaft
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Reduction GearsReduction Gears Reduction Process
Pinion (small) geardrives reduction (large)gear
Reduction ratio = turnsof pinion : turns ofreduction gear
DoubleDouble--reductionreduction:reduction in 2 steps(more compact design)
For naval reduction
gears, normally 30:1
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Reduction GearsReduction Gears Locked TrainLocked Train
Two sets of gears andshafts
Torque transmittedequally
Increases ability totransmit torque usingsmaller components
Turbine shaftsconnected to reductiongears by flexiblecouplings to allow for
thermal expansion
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Shaft Turning/Jacking GearShaft Turning/Jacking Gear Electric motor that
rotates reduction gears,turbines, and shaft w/ousing steam
Cool down turbines afteroperation
Prior to startup for evenheating
Position for maintenance Can be used to lock shaft
in place In event of casualty (i.e.,
loss of lube oil)
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Shaft BearingsShaft Bearings Designed to support the
moving parts of: Shaft
Turbines
Thrust bearings Absorb axial forces
Ex: Kingsbury Thrustbearing
Radial (Journal) bearings Absorb radial forces
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Lube Oil SystemLube Oil System Provide lubrication and remove heat generated by
bearings in overcoming friction
Major components: Sump
Pump
Strainer
Cooler
Bearings
Sump
PumpStrainer
Moving Parts
CoolerSW
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Lube Oil SystemLube Oil System Lube oil can be kept in service for a long
time if kept pure (two methods)
Batch Purification In-port only
Uses heated settling tank
Continuous Purification At-sea method
Centrifugal purifier separates oil &contaminants
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Propulsion ShaftPropulsion Shaft Shaft is hollow: reduces weight & increases
resiliency
Consists of four sections
Thrust shaftThrust shaft - from thrust bearing in reductiongears to end of engineroom
Line shaftLine shaft - located in shaft alley (supported byline shaft bearings)
Stern shaftStern shaft - part of shaft which penetrates hull(supported by Stern Tube bearings)
Propeller shaftPropeller shaft - shaft connected to propeller(supported by Strut Bearings)
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Propulsion ShaftPropulsion Shaft Different sections needed for easy
installation, removal, & maintenance
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PropellerPropeller Made of hub and blades & creates the thrust
necessary to propel the ship through the water
Terms:Pitch:Pitch: axialdistance advancedduring onecompleterevolution of screw
Face:Face: the pressureside
Back:Back: the suctionside
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Propeller TypesPropeller Types Constant vs. Variable Pitch
Variable has the twisted look
Adv: more efficient over widerange of speeds
Fixed vs. Controllable Pitch In controllable, blades can
rotate on hub to change pitch
(change direction) Right vs. Left Hand Screw
Viewed from aft of ship
Twin-screw ships have one of
each
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PropellerPropeller Cavitation
Formation and subsequent collapse of bubbles as
propeller turns Occurs at critical speed
Effects High level of underwater noise
Erosion of blades Vibrabtion with subsequent blade failure from
metallic fatigue
Overall loss of propeller efficiency
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Propeller Power vs. Shaft RPMPropeller Power vs. Shaft RPM Flow E RPM; Thrust (head) ERPM2;
Power E RPM3
So, if 10% power yields 100 RPM, howmuch power will produce 200 RPM?
10% x%1003 2003 x = 10 * (200/100)3
= 80% power80% power
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Questions?Questions?
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