Electrical systems of aircraftElectrical systems of aircraftI.

Aircraft is an equipment capable of • flying (D,M,systems)• Carrying load (purpose)• Partially controlled (inflight reliability is

preconditioned by the quality of special aequipment)

• Brothers Orville and Wilbur Wright – on 17th December 1903, on the beaches of Kitty Hawk performed 4 flights – the first – jump 12s - 56,5 m

the last one 59s – 260 m• handmade aircraft named Flyer I.• financial expenses - 1000 USD• 1905 – lenght of flight 39 km,

• Flyer I flew without any signalization of engine running, no position lights• indicator of height and speed – pilot ´s eyes,

.

Размах крыла, м 11,80

Площадь крыла, кв.м 38,60

Длина, м 8,90

Высота, м 2,44

Взлетный вес, кг. 544

Скорость макс., км/час 70,8

Скорость крейс., км/час 56

Дальность полёта, км ?

Количество пассажиров 1

• Type transport aircraft• Manufacturer Airbus• Maiden flight 27 April 2005• Main user Singapore Airlines• Production since 2002- till now

Output 2,5 -4 aircraft per montlh • Price 319 millions of USD• 525 persons – type with three classes• 853 persons – with tourist class only

• indicator of height and speed – pilot ´s eyes, eaReasr monitoring engine run

• Based on overall feeling, he was judging the proper functioning of the engine

Digest of Aviation Equipment

A-12 Avenger II

Northrop XB-35

Helios – Solar wing

Avionic systems

include PV, EV, VV, RV, RTV, (LWeapons, FV), registration systems, ASR of flight and other electrical and electronical equipment, which enable flying by day and night, under any weather conditions within the determined weather conditions within the determined limits of altitudes and speeds.

Reliable functioning of AV is based on the relia bility of the electro-energetical system (EES).

Electrical equipment of aircraft –development

• 1900-50 – improving aircraft structure and flight characteristics (flaps, undercarriage, bomb-bay, gyroscopes, instr uments, effect of Wwi and WWII ....)

• 50s-70s – increase in speed and operational altitude of flight(introduction of jet-engines, RV, RTV)

• 70s- 90s – automatization of physical and decision-making f or aircrew and integration of systems into a unified system known aircrew and integration of systems into a unified system known as PES (introduction of micro-electronics, integration of systems, reduction in sizes)

• 90s-till now – improvement of aerodynamic configuration of AT, aimeded at: improving maneuvrability of visibility of aircraft, (complex automation of the processes taking place aboard of an aircraft, STEALTH, integration of D+M+LV, thrust vectoring, anthropo-technical requirements – modification in cockpit, maximization of visualization and reasonable da ta presentation)

Aircraft electrical equipment

Electrical equipment of aircraft is made up of : • Sources of electrical power (SEP)• Electrical network (EN)

• Electrical appliances (EA)• Electrical appliances (EA)

AEE is made up of a set of electrical equipment d ivided into groups by their functions, and interconnect ed by electrical conductors to form bases of various aircraft systems.

SOURCES OFELECTRICAL

ENERGY

ELECTRICAL APPLIANCES

ELECTLRICA NETWORK

OTHER ENERGY

OTHER ENERGY

m, s, t, ch... m, s, t, ch...

Aircraft Electrical Equipment – Description

Sources of Electrical Energy

Equipment converting other kinds of energy into electrical energy .

Sources of EE :• Direct current, Alternating Current (kind of el.

energy)• Main, Stand-by (importance)• Primary, Secondary (Generating electrical

energy)

Electrical appliances

• Equipments converting electrical energy into other kind of energy.

• A wide scale of aggregates functioning on various electrical principles. electrical principles.

• By the work performed, they can be integrated int o various functional circuits. (A -sources, B -starters for engines, C -lighting, D – air conditioning, heating, de-

icing, E, F, ... Y, Z)

Electrical network

• Transferring electrical energy from the source t o appliances.

• Direct-current electrical network is based o one conductor (+ conductor, – airframe as earth)conductor (+ conductor, – airframe as earth)

• Electrical network is made up of:1. conductors 4. fuses and protection e lements2. electrical connectors 5. changover switche s 3. distributors of EE 6. mínus connections, jumpe rs

Electrical network

• Conductors – joined into cable bundles sewn over in canvas, ending with MP-FP connectors, fastened to the airframe, marked on the insulator coating.

• Division:– Ø - 0,35 – 90 mm²– Ø - 0,35 – 90 mm²– protective coating – dural, steel tubes, leathercloth,

– thermal resistivity – from 70 °C to 250 °C

Electrical network

• Male plug-Female plug Connectors (MP-FP)To end cable bundles, enable interconnection of f the individual parts of the network, facilitate assembly and disassembly of aggregates, systems and parts of aircraft.and parts of aircraft.

• Division:– common– hermetic – protecting against humidity,– control

Block of commutation

Electrical regulator

Outer view of electrical connector

а) front view

б) rear view

Electrical network

Distributors of el. energy – fusing and switching elements of electrical utilization equipment

are concentrated by their importance on main and auxiliary distributors of switchboard type of distributors o f el. energy.

Main switchboard: integrates control elements of highest importance ( generators, batteries, convertors ...)

Auxiliary switchboard: for elements of lower importance (circuit -breakers)

Elektrical network

Fuses and circuit-breakers• Fuses

– melting,– inertial – having two reaction zones – fast and slow

• Automatic circuit-breakers(bimetallic principle)

a) b) c)

f)e)d)

Electrical network

Bridgings, earthing and minus wiring

• Conductive connection - bridging : selected at places, where the interconnected part are moving inone anothe ´s direction (control system, tubing, block of anothe ´s direction (control system, tubing, block of radioequipment, dashboard etc.), the entire surface of the aircraft is to have the same electrical charge,

• Earthing : cable on a wheel, when filling the fuel tanks ,

• Minus wiring : from generators to the airframe (earth).

a) b)a) b)

c) d)

Basic requirements on AEE

• Reilability and safety• Quality of electr. power• Min. weight and

dimensions• Mech. robustness

• Ruggedness to explosion or fire

• Independence on the position of in the airpsace• Mech. robustness

• Electrical stability• Thermal solidity

airpsace• Operation independent

of pressure, temperature and humidity

• Low level of interference with the radio equipment

Quality of electrical energy is given by

• At an AC power system:

- Phase angle of 120° between phases (116 – 124°),- Sinusoidal form of the curve,- Steady frequency , - Amplitude of the voltage pulse when switching the

appliances On and Off ; - Dividing the appliances between the phases with t he

smallest difference of load (10 %),

Quality of electrical energy is given

• At an DC power system:

- Stable value of the voltage,- Wave-form of the produced voltage,- Amplitude of the puls in the transitional mode and - Amplitude of the puls in the transitional mode and

and load changes, - Quality of attaching the minus clamp to the fra me,

Conditions of operation of the electrical equipment of aircraft

• Air temperature :-60 up to + 70 °C ( v < M)-60 up to +130 °C ( M 2,2 )

• Air pressure:

• Vibrations• Accelerations (+, –)• Schocks (firing)• Inverted position flight

• Air pressure:1OO kPa – on ground5,5 kPa – H = 20 km1,2 kPa – H = 30 km

Airborne system of electric power supply (EES of the aircraft)

Made up of :• System of producing and converting electrical ener gy

- sources of electrical energy (generators = ~, batteries, convertor, power rectifiers, ...)- system of control and protection (equipment to stabilize voltage, frequency, for parallel cooperation, connection, di sconnection, control and checks).

• System of electrical energy distribution – equipment for transmission of EE from the producing part to th e distributory equipments and from them to the appliances.

SOURCES OFELECTRICAL

ENERGY

CONSUMERS OF ELECTRICAL

ENERGY

ELECTRIC NETWORK

OTHER ENERGY

OTHER ENERGY

m, s, t, ch ... m, s, t, ch ...

SYSTEM OF CONTROLLING

AND PROTECTING SOURCES OFEL. ENERGY

SOURCES OF ELECTRICAL

ENERGY

ELEKTRICALNETWORK

OTHER ENERGY

m, s, t, ch...

CONSUMERS OF ELECTRICAL ENERGY

LIGHTING

STARTING THE AE

AIR CONDITIONING

DE-ICING OF AIRFRAME SYSTEMEL. ENERGY

OTHER ENERGY

m, s, t, ch...

SYSTEM OF CONTROL

AND PROTECTION OF SOURCES

OF EL. ENERGY

ASR

ENGINE SYSTEMS

Categorization of appliances - consumers of electrical energy of an aircraft

Appliances of Category 3:- Their failure does not affect continuity of the task and completion

of the flight,

Appliances of Category 2:Appliances of Category 2:- Their operation is a necessary condition to continuity of the task

and completion of the flight

Appliances of Category1:- Their operation is a necessary condition of copmpletion of flight

and landing

Basic types of the aircraft EES

• DC system of EE:- Low voltage 28 V- Medium voltage 270 V

• DC system of EE :- With variable frequency (300 – 900 Hz), - With variable frequency (300 – 900 Hz), - With constant frequency (400 Hz),

• Hybrid system of EE:- Combining DC and ALTERNATING channel of

generating electrical energy

DC system of EES of low voltage 28 V

• Main source – generator of DC ,Driven by the aircraft engine ,

• Standf-by source – board battery

• Supplying DC appliances by the convertor,

The oldest, most proven system in operation, used on small and medium- sized aircraft,

GLM=

• Auxuiliary power source of EE can be a small-size ram-air turbine.

• Power supply to board network on ground from the ground source,

• Disadvantage – limited output of the source is given by the low value of voltage.

GLM

GLM

AKU

POZEMNÝZDROJ

G

S

~

=

=

=

=

1 x 115 V/400 Hz3 x 36 V/400 Hz

24 V

27 V=

CRZ (centrálne rozvodné zariadenie)

The EES of the L -39 jet-trainer

Direct current EES of medium voltage 270 V

POZEMNÝ

LM

AKU

JM

S

~ =

3 x 200 V/400 Hz

270 V=

G ~

~ =

CRZ

• Main source – conntactless generator with DC output, drven by the aircraft engine,

• Stand-by source – board battery• Supplying AC appliances by the convertor,• Feeding DC appliances of lower voltage (27V) from the DC convertor,

POZEMNÝ ZDROJ

PEJ

JM

= = 28 V=

Alternating current EES with variable frequency

(300 – 900 Hz)Serving to feed board appliances of Resistor nature (circuits of heating,

lighting)

• Main source of EE on board of an A/C – gener ator of AC , driven by

TUJ

~ =27 V=

LM G~

AKU

S

24 V

A/C – gener ator of AC , driven by the aircraft engine,

• Main source of DC is a transfo/rectifzing unit TUJ

• Stand-by source of DC – board battery (AKU)

f = 400Hz

115 V/f = var.

S

~=

CRZ

Alternating current EES with constant frequency of 400 Hz

• Main source – contactless generator of alternating current, with stabilized frequency byPKVO, or VPMF (outpput convertor of frequency) driven by the a/c engine,

• Main source of direct current is a transfo/rectifying unit TUJ

TUJ

~ =

3x36Vf = 400Hz

27 V=

LM G3 ~

AKU

S

~=

24 V

PKVO

ω = var. ω = konšt. f = konšt.

a transfo/rectifying unit TUJ

• Stan-by sources of DC – AKU

• Feeding AC appliances from the convertor,

• System used in operation on board of aircraft and helicopters equipped with energeticcally demanding appliances

3x200/115 V/400Hz///CRZ

V P M F

T U J

~ =

f = 4 0 0 H z

3 x 2 0 0 /1 1 5 V /4 0 0H z

2 7 V =

L M

A K U

S

~ =

2 4 V

ω = v ar . f = v ar . f = k o n š t.

/ / /

G 3 ~

~ =

f = v a r .

C R Z

Hybrid EES

3x200/115 V400Hz

27 V

REDUKTOR

LM G3 ~

PKVO ///

LM G

CRZ =

CRZ ~

• It is a combined el. system with DC and AC channe l of generating electrical energy,

• System used for feeding appliances with higher demands on powerand type of EE

27 V=LM G=

OBVODYOVLÁDANIA

A SIGNALIZÁCIEKANÁLU

GENEROVANIA

CRZ

BLOK REGULÁCIEA OCHRANY

K ĎALŠÍMGENERÁTOROM

OBVODYPARALELNEJSPOLUPRÁCE

PREPÄŤOVÁOCHRANA

DIFERENCIÁLNYKOREKTOR NAPÄTIA

REGULÁTORNAPÄTIA

SEKUNDÁRNEZDROJE

ELEKTRICKEJENERGIE

OBVODYPREPÍNANIA

Z DROJOV

LM PRÚDOVÁOCHRANA

=G

NÚDZOVÉ A POMOCNÉZDROJE EL. ENERGIE

SYSTÉMROZVODU

ELEKTRICKEJENERGIE

SPOTREBIČEELEKTRICKEJ

ENERGIE

BLOKRIADENIA

A OCHRANY(DMR)

POZEMNÉZDROJE EL. ENERGIE

OBVODYOVLÁDANIA

A SIGNALIZÁCIEKANÁLU

GENEROVANIA

CRZ

OCHRANAPROTI SPÄTNÝM

PRÚDOM

FREKVENČNÁOCHRANA

f↑, f↓

PREPÄŤOVÁOCHRANA

U↑, U↓

REGULÁTORNAPÄTIA

OCHRANA PREDODBUDENÍM,PREBUDENÍM

KOREKTORFREKVENCIE

OCHRANA PREDNESYMETRICKÝM

ZAŤAŽENÍM

REGULÁTORFREKVENCIE

OBVODYPARALELNEJSPOLUPRÁCE

K ĎALŠÍM GENERÁTOROM

SEKUNDÁRNEZDROJE

ELEKTRICKEJENERGIE

BLOK OCHRANY A RIADENIA

OBVODYPREPÍNANIA

ZDROJOV

U, fPRÚDOVÁOCHRANA

~G

POZEMNÉ ZDROJEELEKTRICKEJ ENERGIE

NÚDZOVÉ A POMOCNÉZDROJE

ELEKTRICKEJ ENERGIE

SYSTÉMROZVODU

ELEKTRICKEJENERGIE

SPOTREBIČEELEKTRICKEJ

ENERGIE

MECH.

OCHRANAPKVOLM ///

Structure of the electrical and energetic system of aircraft

Is given by:

• Purpose of the aircraft (transport, training, bombi ng, .. ),• Required level of reliability of the EES (v,H,)• Required quality of the electrical energy (systems) ,• Operational conditions (t, p, humidity ),• Operational conditions (t, p, humidity ),• Price

Choice of an EES is based on mandatory air norms, TTS established for the given type of aircraft and av iation industry.

DC EES

• Advantages:- Simple parallel cooperation of DC generators,- the possibility of using the generator in regime "s tarter",- large startup torque of motors- simple and economical control rpm of el. engines,- less weight of electric wires in DC network

• Disadvantages:• greater weight and dimensions of machines and contr ol elements,- commutation,- a large part of the DC energy is required to change to the AC

AC EES

• Advantages:- simple voltage transformation (distribution of el. e nergy)- removing the sliding contacts, - Easily convertion AC power to DC

• Disadvantages:- complex system for parallel cooperation of more - complex system for parallel cooperation of more

generators (phase sequence, phase angle α, frequency, amplitude)

- It is not possible to use battery pack as a emergen cy power source

Distribution system of electrical energy

• Equipments for transfering EE from the system of g enerating energy to the distribution, and from them to the appliances.

• Must ensure reliable and continuous feeding of appliances and meet the requirements on maximal operational sa fety and minimal electrical losses and weights.

• By the way of connection of the EE sources to the CRZ, the networks can be divided into: centralized, de/centralized, separated and mixed/hybrid/combined .

• By configuration, they are divided into open, closed and by wiring into radial (parallel), magistral (series) and hybrid ones .

G

G

CRZ 2

CRZ 1

G

G

CRZ G

G CRZ 2

CRZ 1

DECENTRALIZOVANÝ SYSTÉM

CENTRALIZOVANÝ SYSTÉM

ODDELENÝ SYSTÉM

Types of EEs by connecting the source to the CRZ

RZ 1

RZ 3

RZ 2

CRZ CRZ

RZ 1 RZ 2 RZ 3

MAGISTRÁLNA SIEŤRADIÁLNA SIEŤ

Open system electrical energy distribution

RZ 1

RZ 2

CRZ 1

RZ 3CRZ 2

CRZ 1

RZ 1 RZ 2RZ 3

RZ 5 RZ 4

MAGISTRÁLNA SIEŤRADIÁLNA SIEŤ

RZ 4CRZ 2

Closed system of electrical energy distribution

Protection of on-board network and sources of electrical energy

• need to ensure reliable running under any conditions- one of the basic characteristics of on-board network and sources of EE (safe and reliable protection of the network against short-circuit, overload and excess voltage),

• selectivity of protection (switching off only those part of the network, where there is a trouble),

• protection must disconnect and protect both the generator and the network against the destructive consequences of short-circuit and potentail fire.

• protection against excess voltage disconnects the network at failure of generator regulator of voltage from the faulty source before the appliances connected into the on-board network get damaged.

Carbon regulator of voltage and the process of regulation

Differential minimal relay DMR – 400 DSP.

• is designed to both manual and automatic connecti on and disconenction of the dynamo to and from the board network.

Operation:• connecting the dynamo to the board network if its voltage exc eeds that ofthe battery by

0,3 – 0,7 V,

• disconnecting the dynamo from the board network, if its volt age dropsbelow that of the battery and if the reverse current, flowing through it reachesbelow that of the battery and if the reverse current, flowing through it reachesthe value of

15 ÷ 35 A,

• signalling connection and disconnection of the dynamo to or from theboard network,

• not enabling connection of the dynamo to the board network wi thopposite polarity.

DMR – 400 DSP

Excess voltage relay AZP – 1 MB

It protects the DC board network of the aircraft against dangerous increaseof the dynamo voltage in case of regulator failure.(at caking of the carbon column,breakinging the working winding) disconnecting the circuit of the excitationwinding of the dynama and switching off the differential relay.

Excess voltage relay must disconnect the excitation of the dynamo:

a) Maximally at 0,12 ÷ 0,9 with intense increase of voltage on the exciting winding of the dynamo from 15 to 31 Vunder normal conditions winding of the dynamo from 15 to 31 Vunder normal conditions b) Maximally at 0,07 ÷ 0,2 with intense increase of voltage on the exciting winding of the dynamo from 15 to 50 V under normal conditions.

Block diagram of the EES

NORMAL, ABNORMAL AND EMERGENCY MODES OF FEEDING T HE APPLIANCES

1) Normal mode• Three-phase appliances fed by two parrallely operating from the alternator

buses at voltage 3x208V / 400Hz.• Single-phase appliances 115V / 400Hz are feed either by the main and stand-

by transfromer TS/1-2 – bus bar ~ 115V and bus bar of the convertor PO –750A.

• Three-phase appliances 3x36V / 400Hz are fed from the bus bar of the main or the stand-by transformer TS330SO4B.

• One-way appliances are feed from the bus bars of the left and right VU – 6A, operating parallelly with batteries 12SAM – 28, from the bus bars of the batteries I and II. Normal mode of a one-way system is retained even at the failure of one of the power rectifiers.

2) Abnormal mode varises at sudden loss or more difficult control of electrical power systems, occuring not very often and at random, e.g.: failures of parts of electrical power sources, defects in the control mechanism etc. Its duration is short, nending by switchin g on the stand-by source and normal mode is resumed .

3) Emergency mode of feeding arises at the failure on both alternators, both of the power rectifiers or both of the transformers , the TC/1-2 and Tr. TS330SO4B or when the above mentioned failures occure at the same time.

Blok regulácie a ochrany

BRZ-1

15-SCS-45B

15-SCS-45B

ŠRAP-500K

ISA-1K

Rotačný menič

PTO-1000/1500M

Blok ochrany a riadenia

AZU–400AGSR-ST-12/40A

Jednosmerný generátor

LM

KS

+ 27V

Zbernica energouzla jednosmerného prúduZásuvka pozemného

zdroja jednosmerného prúdu

~ 3 x 115V 400Hz

~ 3 x 36V 400Hz

AKU

DCN80

GTDE

Sekundárna zbernica energouzla jednosmerného prúdu

Principle diagram of the energy supply system of the MiG-29

fighter

Regulátor napätia

BRN-120T5A

Blok ochrany a riadenia

BZU SP 376T

Blok ochrany sledu fáz

BČF-208

GT30-NŽ412Striedavý generátor

generátor

LM

SA

ŠRAP-400-3F

transformátora

T-1,5/0,2

Blok transformátorov prúdu

BTT-30BT

Blok ochrany transformátor

a

BZT-1

~ 3 x 200V / 400HzZásuvka pozemného zdroja striedavého prúdu

RMB-1B

GTDE117

NP103A

~ 3 x 115V 400Hz

~ 3 x 36V 400Hz

GeneratorGenerator ofof directdirect currentcurrent GSRGSR--STST--12/40A12/40A

•• StarterStarter -- generatorgenerator GSRGSR--STST--12/40A 12/40A isis usedused asas thethe sourcesource ofof directdirectcourrentcourrent on on boardboard .. NotNot usedused whenwhen in in thethe starterstarter modemode . .

•• In In generatorgenerator modemode itit operatesoperates asas a dynamo a dynamo withwith parallelparallelexcitationexcitation . . CoolingCooling ofof thethe generatorgenerator isis forcedforced –– by by ramram airair (min. (min. speedspeed 600kg/hr)600kg/hr)

Main Main technicaltechnical datadataoutputoutput voltagevoltage 28,5V28,5Voutputoutput powerpower 1212 000W000Woutputoutput currentcurrent 4040 0 A0 Aworkingworking rangerange ofof rpmrpm 4 000 4 000 -- 9 000 min9 000 min--11excitingexciting currentcurrent 1,91,9--15A15Aworkingworking rangerange ofof thethe ambientambient temeperaturestemeperatures -- 6060°°C C -- +60+60°°CC

DesingDesing ofof thethe GSRGSR--STST--12/42A12/42A

11--clamps, 2clamps, 2--cover, 3cover, 3--cable cable eyeseyes, 4, 4--protecting protecting beltbelt, 5, 5--carbon, carbon, 66-- stator body, 7stator body, 7--flange, 8,11 flange, 8,11 ––bearingsbearings, 9, 9--branch, branch,

1010--commutaor commutaor shieldshield, 12, 12--electrical segment.electrical segment.

AccumulatorAccumulator batteriesbatteries 1515--SCSSCS--45B45B

•• AccumulatorAccumulator batteriesbatteries are are designeddesigned to to emergencyemergency feedingfeeding ofofboardboard appliancesappliances atat failuresfailures ofof thethe mainmain sourcesource ofof DCDC –– thethegeneratorgenerator GSRGSR--STST--12/40A and 12/40A and thethe autonomousautonomous startingstarting ofof thetheaviationaviation engineengine..

•• InstalledInstalled aboardaboard thethe aircraftaircraft are are twotwo accummulatoraccummulator batteriesbatteries ofof•• InstalledInstalled aboardaboard thethe aircraftaircraft are are twotwo accummulatoraccummulator batteriesbatteries ofoftype 15type 15--SCSSCS--45B (15 45B (15 -- cellscells, SC , SC ––silversilver -- zinkzink, S , S -- aviationaviation, 45 , 45 ––capacitycapacity in Ah, B in Ah, B -- modificationmodification) ) withwith overalloverall capacitycapacity ofof 80 80 --90Ah.90Ah.

Main Main technicaltechnical datadataOutputOutput voltagevoltage 22 V22 VCapacityCapacity 45 Ah45 AhVoltageVoltage ofof 1 1 chargedcharged cellcell 1,841,84--1,86V1,86V

EES with digital controlClassical types of EES – description:• El. mech. switching elements• A great amount of independent, mutually isolated c ontrol circuits (number, mass)• Analogoue regulators of voltage and frequency with feedbacks,• Complex logical circuits of protection (problematic identification of states),• Large number of single-purpose switches of el. par ametrers without back-up,• Control ensured by circuit-breakers, large amount of conductors of the network

(mass),

Digitally controlled EESs in the 90s became one o f the subsystems of the Digitally controlled EESs in the 90s became one o f the subsystems of the PES, which can no longer be investigated independently nof other systems- description:• Digitally controlled buses (CRZ) – tasked to control feeding of appliances,

to protect and ensure self-control,• Power-based controlled elements (VR Č) and regulators – enable switching on, off,

controlling of performance, protecting the el. ne twork and self-diagnostics,• Contactless power switches (VS)- higher reliability, llower demands on maintenance,

integrating /joining the functions of the switch , regulator of power and protection, smal size, option of controlled start-up and contr ol by microcomputer,

• Sensors with digital output,• Information buses ...

Digitaly controlled EES – contribution• Improving quality of the EE- optimization of th processes of

controlling voltage and the frequency of the gener ator (non-linearity),

• Centralized acquisition and processing of informa tion –possibility of prognosing the state of the feeding system and its elements,

• Ensuring fast protection of the SNEE ,• Ensuring fast protection of the SNEE ,

• Potential for adaptive structure of the SNEE – continuous diagnostics of its own technical status,

• Reducing the number of elements of the technical n etwork and the gth of conductors – integration of circuits of control and protection and their interlinking,

Trends of further development of board systems of supplying EE

• Characteristic feature of developing the PSNEE – e fforts made to achieve max. Energy efficiency and minimalization of fuel consu mption – development of the theory on PEL.

• PEL – efforts made to replace the existing airframe hydraulic and pneumatic systems by an electrical system as the only primary system of energy (supply?).

• Energy taken from the power plant is used only to drive the electrical aggregates, which should replace the hydraulical and pneumaticaal systms in use. (Until now could not compete with the hydraulic al ones in terms of specific performances and dynamic cha racteristics).systms in use. (Until now could not compete with the hydraulic al ones in terms of specific performances and dynamic cha racteristics).

• Conditional fact to realizing the PEL is desinging reliable electro-mechanical drives, which will replace hdraulic one s.

• Concept of PBW (power by wire) and its trends by areas:- autonomous electrical drives of aircrafts- development of new power plants with integrated source of EE- electro-pulse (fly-by-wire) de-icing system

- System of cooling and air conditioning using el ectrical drives - System of automated self-control based on elemen ts of artificial

intelligence- Transfer of information using optical fibres- Digitaization of information processes on board of aircrafts- using

data buses

- Modernization of the main sources of EE is made th rough improving the design of contactless generatorsimproving the design of contactless generators

Contributions of the PEL:- Reducing fuel consumption and mass of aircraft- Simplifying technical servicing,- Improving operational reliability- Improving the dynamical characteristics of aircra ft control

Airborne synchronous generators

Excluding the PKVO eliminates a number of disad vantages of this desing:

• Short service-life, high operational losses, lower efficiency, lower effictivity of th P-G system, poor quality of tra nsitional processes,

Contribution of the new design:• Advantageous fitting and bedding of G, faster re action, potential

for integrating/joining the MF with the regulato r of frequency and voltage, high quality of the produced el. energ y, better conditions of parallel cooperation of the G.

Elektro – hydrostatický pohon EHAEHA (electro – hydrostatic actuator)

- Has its own oil tank, battery and hydraulic pump gen erating hydraulic pressurefor the piston connected with the control system of th e aircraft (hydraulic "mini-

system"), el. energy is taken from the onboard netw ork of the aircraft.

- has a small size, can operate in extreme climatic cond itions, is resistant toelectro-magnetic interference.

• EHA allows decentralization the structure of the hydraulic system of the entire aircraft.,

• Produce the energy required for movement of the working cylinder in place where it is necessary

• The weight of the hydraulic system was reduced and overall safety of the aircraft was increased.

Hydraulic EBHA with electrical back -up

• In normal modeWorking as a conventional hydraulic servo-drive fed by on-board hydraulic distribution system,

• In case of damages or losses of pressure in the hydraulic system it will automaticky switch-over to mode EHA.

Airborne contactless synchronous generatorswith permanent magnet

The most frequently used types of generator rotors with permanent magnet excitation

The most frequently used types of generator rotors with permanent magnet excitation

Atomic number Name Chemical sign

57 Lanthan La

58 Cer Ce

59 Praseodym Pr

60 Neodym Nd

61 Promethium Pm

62 Samarium Sm

63 Europium Eu63 Europium Eu

64 Gadolinium Gd

65 Terbium Tb

66 Dysprosium Dy

67 Holmium Ho

68 Erbium Er

69 Thulium Tm

70 Ytterbium Yb

71 Lutecium Lu

Magnetic materials of permanent magnets

• Hard magnetic alloys - Al, Ni, Co – with variable contents of Cu, Ti, and30 – 50% Fe

• Alni -(13%Al, 27% Ni), AlNiCo (8% Al, 13% Ni, 22% Co + Fe) – magnetic properties do not depend on temperature, mean valu e of B.H, electrically conductive, less resistive to demagnet. effects of the external field, substantial irreversible demagnetization.

• Ferrite magnets – DUROX (sintered Fe O s BaO, or SrO) – Low • Ferrite magnets – DUROX (sintered Fe 2O3 s BaO, or SrO) – Low dependence of the magnetic properties on temperatu re, lower product of B.H, el. non-conductive, resitive to demagn. Effec ts of external fields, high coercitive power, lower valu e of the remanent induction(Br).

• Permanent magnets – compounds of Sm, Ce, Pr, Th, Nd, with Cobalt Co (e.g. SmCo 5, PrCo 5, Sm2Co17 (VACOMAX), Nd-Fe-B (VACODYN), high value of remanent induction(Br), coercitive power, low dependence on temperature, high value of B.H, el. conductive, r esistive to the demagnet.. Effects of external fields, magnetic conductivity as ferrites.

Airborne contactless synchronous generators with rotating rectifyier- with dependent excitation

Airborne contactless synchronous generators with rotating rectifier - with dependent excitatio n

Airborne contactless synchronous generators with rotating rectifier– with independent excitation

PBHGB

RU

Contactless generators of alternating current

• Main advantage – altitude-worthiness, smaller dimensions,

• They are devices with non-traditional ways of exc itation, as required, they can have either an AC or DC outp ut.

Contactlessness is achieved by:• Excitation of the generator by means of a n AC exciter via a

rotating rectifier• Excitation of the alternator by a permanent magnet ,• Combined excitation of the alternator,• Further improvements of sources systems leads to the

developpment of an integrated design of „contactle ss generator – converter of frequency“ – without using t he PKVO

Basic laws of electrotechnics

1. Law of electromagnetic induction – of Farraday ; Maxwell´s formulation – in a direct conductor moving in a homogenous mag netic field a voltage directly prportional to B,l, v is induce d.

dΦe = B.L.v ; e = B.L.v. ; e = - ––––– [ V, Wb,s]

[ V, T, m, m/s] [ V, G, cm, cm/s] dt

e – voltage induced in the conductor, B- magnetic i nduction of the field, L- length of the active part of the conductor, v - speed at which the conductor is moving

810−

of the active part of the conductor, v - speed at which the conductor is moving(Rule of the right hand)

2. Law of the electromagnetic forces – transition of current in the conductor, which is in a magnetic field is accomp anied by generation of power, the magnitude of which is porportional to L,B, I.

F = B.L.I [ N, T, m, A] F = B.L.I [ kp, G, cm, A]

F – el. magnetic power acting on the conductor, B- m agnetic induction of the field, L- length of the active part of the conductor , I – current running through the conductor, (Rule of the left hand)

81,9

10 6−

3. Low of overall current – the curve integral of the vector of the magnetic field intensity along a circuit is equal to the overall current closed by this circuit

Which for the electromotr can be described as:F e

dH =→→

∫ l

ei

n

ii

FH =∑=

l.1

8

The sum of magnetic voltages of the sections is equal to the magnetic voltage of the circuit.

Φ – magnetic flow [ Wb = Vs = M ]B – magnetic induction [ T = Wb/ = M / = G ]H – magnetic field intensity [ A(z) /m ]S –cross-section of part of the circuit [ ]l - lenght of the mean power-curve [ m ]F – magnetic voltage [ A(z) ]µ – permeability [ H/m]

8

8102m 410 2cm 410

2m

Basic information on DC electromotors

• DC electromotors are used to convert electrical energy into mechanical work and vice versa.

• DC E motors consist of:- Stator wit poles and exciting winding- Anchor with working winding- Collector with a system of brushes

Princople of operation:• Generating the magnetic fields of poles,

source• Rotating the anchor in it (in the magn. field) • Collecting voltage on the system of brushes

(feeing the appliances) – generator. Feeding the anchor via the brushes –

electromotor. Interchangeability discovered by E.CH.Lenz

Winding forming a closed circuit of sections in series connection and is divided into two parallel.

In each branch voltage is made up of the voltage from the section in series connection and their direction is indicated with arrows.

Brushes are located into the exes of poles and touch the exes of poles and touch the electrical segments to which the sections are connected in a geometrically neutral position.

In sections in neutral position no voltage is indicated .

Winding forms a closed circuit of sections connected in series and is divided into two parallel branches .

In each branch voltage is made up of the voltage of sections connected in series and their direction is marked with

Movement of current in parrallel branches

direction is marked with arrows.

Brushes are located into the axes of the poles and touch the the electrical segments to which the section are connected in geometrically neutral positions.

In sections in neutral positions no voltage is induced.

Excitation of the electromotor (engine)

• The working of and electromotro is necessitated by the presence of magnetic flow , which is generated by excitation .

• It can be generated zby a • It can be generated zby a separate motor , or by its own motor.

• By way of excitation, electromotors are divided into:- motors with foregin excitation- motors with their own excitation

Basic equations of DC electromotorsInduced voltage of the anchor windingPoles´ extensibility speed of anchor rotation magn. flow of the pole pair

coeffficient of pole coverage

voltage induced in one conductor

induced voltage of the motor. .str stre B l v=

p s trb B

B δ

ατ

= =

.

2

D

p

πτ = . .v D nπ=

. 2 .D pπ τ=2 . .v p nτ=

. .strB l τ = Φ

n– rpmp- number of pole pairs

- poles ´ extensibility τ.2a str

NE e

a=

. . .2a str

NE B l v

a=

. .2 . . .2a str

NE B l p n

aτ=

. . . . . .a K e

NE p n C n k n

a= Φ = Φ = ( , , , , , , )a strE f p n N a l Bτ=

- poles ´ extensibility N- number of active commuting conductorsa – number of parallel branchesl – length of the conductor under the pole, actual/active partBstr- value of the magn. Induction in the air gap

- magn. flow of the polesCk- design constantKe- el-magn. Constatn of the motorD- diameter of the anchor

τ

Φ

Electromagnetic momentum of the DC electromotor

1 . .em aF B l iδ=

1 1 2.

2.. .e em am F B

Dl

DiM δ= = 2

aa

Ii

a=2. .

.2 2 2.

D D pπ τπ π

= =

1 .. . .. .2

.em m ae BD

NM i NM lδα α= =

2.. .

... . .

2. .

2 2a

em a

I pB l N

NI

a

pM

aδτ

πα

π= Φ=

. .strB lφ τ=

n– rpmp- number of pole pairs

- poles´ extensibility N- number of active commuting conductorsa –number of parallel branchesl – length of the cunductor under the ople, activeBstr - value of magn. Induction in the air gap

τ

Φ22 2a aππ

. . .em M a M aM C I k I= Φ =

eMM M Mo= −

eMM M Mo= +

( , , , , , , , ) ( , , , , , )em a aM f p N a B l I f p N a Iδτ α= = Φ

Bstr - value of magn. Induction in the air gap - magn flow of the poles

Cm- design constantKm- el-magn. Constant of the motor

Coefficient of pole coverageD- diameter of the anchor

α

Φ

Effective momentum of the motorRequired momentum of the motor (for a generator)

Mo

Breaking momentum of the generator

Momentum of idle run for the engine

Mo

Dimensional equation

Dimensions the electromotor depend on: magn. Induction in the air gap Bδ, rpm of the anchor

n, coeff. Of the pole´coverage α , and flow density of the anchor A..

.ai N

ADπ

= Flow density Of the anchor circumference

. .a

A Di

N

π=

.2I i a=

. . .. . . . . . . .2

2em

N D A DP p n B l a

a p Nδπ πα=

. .strB lφ τ= .strB Bδ α= .

2

D

p

πτ =.2a aI i a=

. ..2 .2a a

A DI i a a

N

π= =

0.em aP E I=

0 . . .N

E p na

φ=

. ..2 .2a a

A DI i a a

N

π= =

2p2 2. . . .. . .emP A D nB lδπ α=

2. . . .em essP c D l n=

El. mag. výkon

n–rpmp- number of pole pairs

- poles´ extensibility N- number of active, commuting conductorsa – number of parralel branchesl – length of the conductor under the pole, active partBstr- value of the magn. Induction in the air gap

- magnetic flow of the polesCk- design constantKe- el-magn. constant of the motor

τ

Φ

Esson´s coefficient characterizing utilization of active materials of the motor vby way of performance per unit volume of the pri sm pof the described anchor at one revolution per second .

2. .em

ess

Pc

D l n= 3/ . /W m ot s

Reaction of the anchor at DC electromotors

BV of the motor generates the magn. Flow of the poles:

- It directs from north to south,- it is symmetrical to the geom.

neutral.

- By turning the anchor of the generator in the magn. Field of the poles, motional voltage is induced in its winding, if the brushes get in its winding, if the brushes get connected to the load, current will run through the winding.

- The current flowing through the anchor winding will generate its own magnetic flow – the anchor when loaded represents an electromagnet , the magnetic flow of which is distributed around the geometrical neutral , running through the brushes. .

- When turning the brushes by a

In fact, there are no tweo flows in the electromo tor – that of the poles´ and the anchor , only one

generated in conjunction by mutual interaction of t he two flows .

Definition: the effect of the anchor magnetic flow ( when tapping current from the generator ) on the magnetic flow of the poles leads to generation of a resulting magnetic flow in the mo tor, termed as REACTION OF THE ANCHOR.

The resulting flow is divided under the poles unequally : under the otrailing edge of the pole it is amplified, punder the leading edge of otrailing edge of the pole it is amplified, punder the leading edge of the pole it is weakened. Thus, due to the anchor reaction the axis of the resulting magnetic flow is turning by a certain angle into the position termed as magnetic neutral.

Lonmgitudinal and lateral components of the

magnetic voltage of the anchor• If the brushes are positioned in the

geometrical neutral , the magnetic field of the anchor is vertical to the magnetic field of the poles of the motor and is termed as LATERALL(Y).

• If the brushes are positioned in the axis of the poles , bthe axis of the anchor field will be identical with the the axis of the poles of the motor and the pole will be poles of the motor and the pole will be tered as LONGITUDIUNAL(LY).

• The effect of this voltage on the flow of main poles depends on the direction of he brushes are turned with reference to the geometrical neutral.

+ 90° - acting demagnetizingly,- 90° - acting magnetizingly,± β - present in the motor are both the

longitudinal and lateral components .

• Conclusion:

• Anchor reaction reduces the resulting flowunder the leading edge of the poles and punder the otrailing edge amplifes it.

• If the brushes are in geometrically neutral position, the lateral field of the anchor deform the field of the poles, and as a result the neutral will be shifted into physical neutral.

• Reacion of the anchor may cause sparking on the commutator. on the commutator.

• Magnetic flow of the motor (poles) when loaded will be lower than when idling.

Eliminating the anchor reaction• Using a compensatory winding in series

with the anchor winding – makes the motor more expensive,

• Shifting the of brushes into the physical neutral.

Pecularities of the anchor reaction- Generators• Caused by drives with variable rpm (AE) – to maintain constant voltage on the

clamps of the generator, it is necessary to chang e IB.

• Anchor reaction is demonstrated at different revolutions of the motor and also depends on the magnitude of the loading current.

- Electromotors• In electromotors current runs against the direction of the induced voltage, and

therefore the anchor reaction is of opposite by nature as it is with the generators . It therefore the anchor reaction is of opposite by nature as it is with the generators . It acts demagnetizingly on the trailing edge of the po lesand magnetizingly on the leading edge of the poles.

• Shifting the brushes from the geometrical neutral in direction of turning the anchor generates magnetizing voltage of the anchor reaction , when shifting against the direction of turning the anchor demagnetization vo ltage is generated .

Commutation of DC electromotors• When shifting the anchor of the previous secti on of its winding from one parallel branch into the other, voltage in them is changing from a certain value of one sign into the one of opposi te sign.

• The process of changing the flow in the anchor se ction, which is short-circuited by the brush when transiting from o ne parallel branch into the onter is termed as commutation.

Process of commutation.

Straight-line comutation(an infinitely slow motion)

• The current in the commuting coil is changing linearly, slowly, in terms of its magintude and direction.

• Its magnitude on the in the segment • Its magnitude on the in the segment depends only on the magn itude of the transient resistance of the leayer between the brush and the commutator.

• Current at commutation increases or decreases in direct proportion to the change of the contact area between the brush and the segment.

Curve commutation(normal motion of the anchor)

If the commuting section is in position of the physical neutral, turning the anchor induced in it are phenomena such as:

• Motional voltage ek – as a result of the anchor motion in the magnetic field

• Self-induced reaction voltage er as a result of changing voltage in the section, which is being commutated,section, which is being commutated,

• Voltage of mutual induction em –generated in case when the brush is wider than the segment of the collector, simultaneous commutation takes place in several sections, from other conductors,

• Owing to them, in the commutatin section and additional commutation current in is flowing, which si the sum of kstraight-line commutation and the additional current.

1-straight-line, 2- delayed, 3-delayed el and ek are simultaneous),4-accelerated( ek>el ), 5-speeded up ( ek>>el )

Ways of improving commutation

• Turning brushes into the physical neutral – the brushes must be turnes by a certain angle against the direction of turning the anchor (when changing the load of the motor, the position of physical neutral changes too, consequently the positions of brushes is to be changed changes too, consequently the positions of brushes is to be changed accordingly. A thing difficult to perform in prac tical life.

• Using auxiliary poles, when mplemented between the main poles into the physical neutral, they are narrow, there by generate commutation field only in the field of commutation, excitation of the auxiliary poles – dinto a series with the ancher, inducing ek flowing in direction against the er.

• Using a special winding of the anchor,

Commutator and the collector mechanism – technologically the most demanding part of a DC electromotor , active, made up of alloy segments, mutually insulated, appropriately profiled,

Commutator• Motors up to 3kW – possibiity of air cooling the surface

even from the internal part • Motors with higher performance- featuring a split

commutator (commutators display low level of run-out(flapping).

• Collector mechanism - carbons are flexibly positioned in

Dezing of the lsiding contact of the aviation dy namoes and conditions of operation (wear of carbon)

• Collector mechanism - carbons are flexibly positioned in holders, emphasis is put on the sliding contact between the brush and the commutator, design depends on the performance, rpm of the electromotor,

• Suirface of the commutator is covered with a p olished layer (filmom), as a result of chemically active a gents the thickness of the layer is increasing while impai ring contact.

• Removing the film results in rapid wear of the b rushes, and at higher altitudes it becomes necessary to u se special types of brushes, important role is played by the design of brush-holders – reliable, stiff, resistin g vibrations.

Popt – optimal pressureP < Popt – wear due to vibrationsP > Popt –wear by friction