Assignment On Aircraft Power Systems

Assignment On Aircraft military social unit placementsIn this assignment, I int repeal to fork up a brief presentation about the rationale of operation of the aircraft electric great indicant schemas, specifically, Integrated Drive references (IDG) in a groundbreaking aircraft. I will comp ar and contrast the fluid and electrical methods of powerfulness generation and give a brief on the natural rubber precautions to be followed when handling aircraft electrical power supplies and during a raceal test. in that location are various kinds of power generation on an aircraft, namely electrical ( sources batteries), fluid (hydraulics pneumatics). Depending upon the application, the power sources may vary. product lineCRAFT galvanizing SYSTEMThe briny function of any aircraft electrical establishment is to bear, regulate and distribute the electrical power in the aircraft. Modern aircrafts drop more electrical power as they are equipped with more Electronic shoot Inst rument administration (EFIS). This is done so as to reduce pollution in the environment, for a clean and safe f blowsy.electric automobileal power is employ to operateAircraft Flight Instrument- Electronic Centralized Aircraft Monitoring (ECAM)Essential Systems- Primary Flight bring out (PFD), Navigation Display (ND)Passenger Services- In-Flight Entertainment (IFE)Most of the aircraft systems use a power standard of 115 emailprotected 400Hz 28VDC.There are various electrical power sources on the aircraftEngine Driven AC Generators (EDG) accompaniment causation Units (APU)Ram Air Turbine (RAT)Battery summateExternal/Ground Supply (Spoor, 2012)Components in an electrical system allowAC Generator/Alternator produces AC power.Constant Speed Drive Unit (CSDU) regulates the rotating hie (input) to deliver a in changeable output from the engine to the beginning.Integrated Drive Generator (IDG), Generator and CSDU committed either coaxially or side-by-side. Mostly coaxial connecti on.Transformer Rectifier Unit (TRU) converts the AC power to DC powerGenerator Control Unit (GCU) monitors and controls the generator output.Each engine powers up one or more generators. Airbus A380 has quartette engines and four generators. Whereas, Boeing 777 has two engines and two generators. The power produced by these generators is used to power up the entire aircraft. (Boeing, 2012)All the other power sources, except orthogonal total, are used in case of emergencies only.External power supply is used on ground when the engines and the APU are not running. It is supplied via Ground cater Unit (GPU). GPU can be portable or stationary and they provide AC power through the external plug on the twine of the aircraft. They can be used to power up an entire aircraft or a specific area in the aircraft. (Spoor, 2012)Figure Aircraft Electrical System (Classic Jet Sims, 2012)AIRCRAFT HYDRAULIC SYSTEMThe principle of a hydraulic system is to convert fluid power into mechanical power and then use it for various applications on the aircraft, such as extension/ retraction of get gears, flaps, and speed and wheel brakes.The power source here is the hydraulic fluid. The coerce for generating the hydraulic power is supplied by the Engine Driven Pump (EDP) and the Electric Motor Driven Pump (EMDP). They are both mounted on the engines.Commonly used hydraulic fluids on the aircraft areMIL-H-5606 (Mineral ground Fluid)MIL-H-83282 (Synthetic Hydrocarbon Based Fluid)MIL-H-87257 (Same as MIL-H-83282, but it has been improved in its low temperature viscosity)MIL-H-8446 (Phosphate-Ester Based Fluid) (Wikipedia, 2012) picky care must be taken when handling the hydraulic fluid. any(prenominal) of the hydraulic fluids are skin/eye irritant. Also it is extremely key for the fluid to be free from any contamination for flight safety.Advantages of the hydraulic system as a power source intromitsLight weightiness favorable installation simplified InspectionMinimum Maintenance Approximately ascorbic acid% system efficiency, with only negligible loss due to friction. (EAC, 2012)Figure radical Hydraulic System (Free Online Private Pilot Ground School, 2006)COMPARISON OF AIRCRAFT ELECTRICAL AND HYDRAULIC SYSTEMFEATUREELECTRONICHYDRAULICConstruction major power is generated by the engine, by rotation of turbine shaft.Power is generated by incompressible hydraulic fluid. Pressure for hydraulic actuation is supplied by EMDP and EDP.Similar to that of an electric circuit.Components include Generators/Alternators, Batteries, Switches, Bus bars, Fuses, Circuit Breakers, Voltage Regulators, Ammeters, and Wires. (Free Online Private Pilot Ground School, 2006)Components include Reservoir, Pump, Hydraulic Fluid, Accumulators, Actuators, Filters, Hydraulic Fuses, Tubing, Pipes, Valves, and Seals.UsesLights, Radio Equipment, Indicators, Warning Systems, Heaters, Starting beat back. (FlightLearnings, 2012)Extension/retraction of landing gears, flaps, and speed and wh eel brakes.Principle of OperationGenerate, Regulate and reel electrical power generated.Work is done by moving an incompressible fluid, Pascals Law. (EAC, 2012)EMERGENCY DEPLOYMENTS IN EVENT OF GENERATOR(S) FAILUREIn case of main engine driven generator (EDP) failure, there are various methods to chequer continued power supply for safe landingAuxiliary Power Unit (APU)Ram Air Turbine (RAT)BatteryWhen the main engine generators fail, APU or RAT is deployed. When the secondary methods fail, batteries are used as the last lose for a safe landing and evacuation.AUXILIARY POWER UNIT (APU)Auxiliary Power Units (APUs) is a small gas turbine engine which provides electrical, hydraulic and pneumatic power (depending on the design) for ground or in-flight operations. It is as well used as a backup source in emergency situations. It is commonly rig on large aircrafts. It is usually located in the tail end of the aircraft. When started, it normally runs on 100% speed. It produces 115VAC 4 00Hz. Some can also generate 28VDC.The main purpose of the APU is to start the engines in the aircraft. This is because the engine requires high rotational speed for its self-sustaining operation. In this case, APU is started by battery or hydraulic accumulator and then used to generate the necessary rotational speed. It is also used to run the equipment when the engines are shutdown. This is used for air conditioning for the passengers forward to engine start. However, it can also be machine-accessible to a hydraulic pump to power up hydraulic equipment (flaps and flight controls). (Wikipedia 2012)RAM AIR TURBINE (RAT)Ram Air Turbine is a small airflow driven turbine that is connected to either a hydraulic pump or an emergency alternator or a main generator. In normal flight, it is stowed away in closed(a) compartment in wing or fuselage. It is deployed only when there is total power loss due to engine failures. It provides enough power to run the critical systems, such as, fli ght controls. The power generated by the RAT depends on the airspeed. to a greater extent the speed, more the power generated will be. Some aircrafts use RAT in normal operation. For example, in crop dusting RAT is used to power up the chemical sprayer. (Wikipedia, 2012)BATTERYAircraft batteries are used to start the engines or the APU. further they are also used in emergency situations as a last resort for safe landing. There have been cases where it has been used to re-start the engines even after engine flame-out. They also act as a buffer for the DC connections. It regulates the voltage to ensure the power quality for the equipment connected to it.Two types of batteries are used in aircrafts today, Lead-acid and Nickel Cadmium (Ni-Cd). Lead-acid batteries are either valve regulated or vented. They are used in light and general aircrafts. Ni-Cd batteries are used in larger aircrafts. Lead-acid batteries are slackly heavier and have slight capacity than the Ni-Cd ones. (Dr. Th omas, 2010)Figure Lead-Acid Battery (Chief Aircraft, 2012) Figure 4 Nickel-Cadmium Battery (Surplustraders.net, 2012)AIRCRAFT ELECTRICAL SYSTEM USING FREQUENCY WILD AC GENERATORFrom 1950s to early 1960s some turboprop aircrafts used frequency wild, now inconstant Frequency (VF) system. Airbus A380 and Boeing 787 Dreamliner are some of the modern civil aviation aircrafts that have adopted the VF system again.Figure Simplified Frequency Wild System (Scribd, 2012)CONSTRUCTIONAs shown in Fig.4, the Variable Frequency Generator (VFG) is directly connected to the engine gear box. (Langlois, 2004) states VFG is a conventional wound rotor synchronous alternator. There is no CSD or IDG in this system. This is done so as to improve the reliability of the system and also to reduce the weight of the aircraft. Airbus A380 uses aluminium cables instead of copper for weight reduction. The system is also fully computerized. Contactors and Breakers have been replaced by substantiality devices fo r increased reliability and performance (Global Aircraft, 2012).OPERATIONFrequency Wild AC power can only be supplied to the resistive circuits such as the electrical heater, engine de-icing heaters, windshield heating, etc. as shown in Fig. 4. The AC power generated is sent to the TRU where the voltage is stepped down from 360Hz-760Hz (Langlois, 2004) to 28V and then rectified to DC voltage. Then it is used by the DC components.CONTROL PROTECTIONA traditional Constant Frequency unit has only a constant frequency of 400Hz voltage supply. A constant speed drive unit drives the generator. It is also expensive and not easy to maintain. A VFG is flexible as it can handle a range of frequencies rather than a constant one. In this unit, there is no CSD or IDG. It is more advantageous oer Constant Frequency Unit becauseIt has low maintenanceLong livelinessCheaperProcess temperature is controlled within VFG itself.Equipment protection from excess torque damageThe variable frequency genera tor (VFG) is used on applications with a high helping of resistive AC or DC loads and provides power to umpteen of the next generation aircraft. Hamilton Sundstrands variable frequency starter generator (VFSG) and motor controller system provides main engine start and control.The voltage is controlled just about the generator. This is done by controlling field strength of the AC generator by feedback signal from the voltage regulator, which keeps the voltage constant irrespective of the speed and load variations.VFGs are preferred over DC systems because they were much less affected by poor brush performance at high altitudes and they had better power to weight ratio.AC/DC ELECTRIC laborS AND ACTUATORS procedureDC actuators are typically high-speed reversible series-wound motors. Their output is converted to driving torque using step-down gearbox. These motor actuators are collected units, as they combine both electrical and mechanical devices. They can practise linear thrust over a short distance.AC MOTORDC MOTOR