Canadair Regional Jet 100/200 - Electrical1.INTRODUCTIONThe aircraft uses both 115 Volts AC and 28 volts DC power. AC electrical power is providedby two engine-driven generation systems. Each system includes an integrated drivegenerator (IDG) and a generator control unit (GCU). An auxiliary power unit (APU)generator is also available as a back AC power source to replace either or both IDGs.In the event of total AC power loss, emergency AC power is available from an in-flightair-driven generator (ADG). The ADG assembly is stowed in a compartment on the rightside of the nose section.DC power is supplied by five transformer rectifier units (TRU) which rectifies AC input powerinto DC output power. Another source of DC power is from a main battery and APU battery.The main and APU batteries are connected into the aircraft DC electrical power system andare charged by their respective battery chargers. Power for starting the APU is provided bythe APU battery.Electrical contactors, switches and relays located throughout 13 junction boxes in theaircraft, are used for connecting AC and DC power to the appropriate buses andcomponents. Power connection is dependent on system configuration and health. Thefollowing is a list of all the aircraft electrical system buses:DC BUSSESDC BUS 1AC BUSSESDC BUS 2AC BUS 1DC ESSENTIAL BUSDC SERVICE BUSAC BUS 2AC ESSENTIAL BUSLEFT AND RIGHT BATTERY BUSAC SERVICE BUSADG BUSDC EMERGENCY BUSDC UTILITY BUS 1DC UTILITY BUS 2AC UTILITY BUS 1AC UTILITY BUS 2MAIN BATTERY DIRECT BUSAPU BATTERY DIRECT BUSOn the ground, the aircraft can receive external AC power through a receptacle located onthe forward right side of the fuselage. The aircraft can also receive external DC through areceptacle located on the aft right side of the fuselage.The electrical power services panel (EPSP) in the flight compartment, and the externalservice panel on the right forward fuselage, contain the AC and DC system control switches.The switches are used for manual and automatic control of the electrical power generatingsystem and external power operation.Page 1

Canadair Regional Jet 100/200 - ElectricalElectrical system warnings and cautions are displayed on the EICAS primary page. Statusand advisory messages are displayed on the EICAS status page. General views of theelectrical systems are displayed on the EICAS, AC and DC synoptic pages. The AC and DCsynoptic pages are accessed through the EICAS control panel (ECP). One push of theELEC key on the ECP will display the AC synoptic page. Pushing the ELEC key a secondtime will display the DC synoptic page.Page 2


Canadair Regional Jet 100/200 - ElectricalExternal Service PanelRight Forward FuselageElectrical Power PanelOverhead PanelFlight Attendant Panel&RQWURO 3DQHOV)LJXUH Page 4

Canadair Regional Jet 100/200 - Electrical1.AC ELECTRICAL SYSTEMAC power for the aircraft electrical systems is provided by two engine-driven, integrateddrive generators (IDGs) which supply power to all AC buses during normal operations. AnAPU generator provides a backup AC power source in flight if an IDG is inoperative or whenthe aircraft is on the ground with the engines off. If all AC power is lost in flight, emergencyAC power is provided automatically by a deployable air-driven generator (ADG). The ACdistribution system is controlled by the respective IDG and APU generator control units(GCUs). Each generator is monitored by the GCU’s for voltage, frequency and kilovolt amps(KVA) to provide system fault protective shutdowns. An AC power distribution schematicand system parameters are displayed on the EICAS AC synoptic page.A.Integrated Drive Generator (IDG)Each IDG consists of a constant speed drive (CSD) and a generator. The CSD uses aninternal oil system to hydro--mechanically change the variable input speed from theengine accessory gearbox to a constant output speed to the generator to produce115--volts AC and to maintain a constant frequency of 400 Hz. Each generator is ratedat 30 kilovoltamperes (KVA) up to an altitude of 35,000 ft., then 25 KVA to 41,000 ft.An oil cooler cools the oil used by the IDG. Each IDG is monitored for low oil pressureor high oil temperature. In the event of low oil pressure or high oil temperature, an(amber) FAULT light (cover--guarded) on the EPSP will illuminate. Lifting thecover--guard and pushing the switchlight will manually disconnect the IDG from theengine gearbox.The IDG will automatically disconnect if a severe oil overtemperature or overtorquecondition occurs. Once disconnected, either manually or automatically, the IDG cannotbe reconnected in flight. If the IDG was disconnected manually, it can only be reset onthe ground, with the engine shutdown. If the IDG was disconnected automatically, itmust be replaced.Each generator control unit (GCU) controls and monitors the related AC generatorsystem and provides voltage and frequency regulation and fault protection for itsrespective generator. The GCU also protects the electrical system from overcurrentand differential current faults. In the event of a malfunction, the GCU will automaticallydisconnect the faulty generator from the respective AC buses. The generator may bereset when the malfunction is corrected or no longer exists, by selecting the generatorswitch to the OFF/RESET position then back to ON.B.APU GeneratorThe APU generator is driven, directly by the APU gearbox, at a constant speed tomaintain a constant frequency output. The generator provides 115--volts, 400 Hz ACpower and is rated at 30 KVA from sea level to 37,000 ft. A GCU, identical to the IDGGCU, provides the same regulation and protection functions as the IDG GCUs.C.AC DistributionTwo different configurations of AC power distribution are available, Full configurationand Service configuration.Page 5

Canadair Regional Jet 100/200 - ElectricalIn Full configuration, all the AC buses are powered using either IDG 1, IDG 2, the APUgenerator or external AC. For normal AC distribution, AC power from IDG 1 and IDG 2is distributed to all the AC buses via GCU controlled contactors in junction box 1 (JB1).There is a priority control of AC power distribution. During normal operation, IDG 1powers AC bus 1 and IDG 2 powers AC bus 2. The failure of a generator, for anyreason other than a fault on its associated bus, will automatically transfer the load fromthe failed IDG to the remaining operative IDG. When the APU generator is available, itcan then be used to replace the failed IDG to power the respective AC bus. On theground, if the aircraft is being powered with external AC power and either the APU oran IDG is brought on line, the external power will be automatically disconnected and therespective APU or IDG generator will power all the AC buses. When external power isnot available, the APU generator provides electrical power to all the AC buses. If anIDG is powering its respective AC bus and the APU generator is powering the other ACbus, when the remaining IDG is brought on line the APU generator will be automaticallytaken off line.In service configuration, either external AC power or the APU generator is used topower specific buses for general servicing of the aircraft on the ground. Only AC Utilitybus 1, AC Utility bus 2, the AC service bus and the DC service bus are powered.,'* 38 *(1(5 725)DLOHG1RW DYDLODEOH)DLOHG & %XV %RWK & %XV DQG & %XV & %XV 1RW DYDLODEOH)DLOHG & %XV )DLOHG%RWK & %XV DQG & %XV )DLOHG%RWK & %XV DQG & %XV & %XV )DLOHGPage 6,'*


Canadair Regional Jet 100/200 - ElectricalAC ESS XFERUsed to switch essential bus feedfrom AC bus 1 to AC bus 2.ALTN (white) light indicatesessential bus is fed from AC bus 2.Transfer is automatic during an ACbus 1 failure.IDG 1 and 2 DISC(Guarded)Used to disconnectIDG from engine.DISC (white) lightindicates selecteddisconnect is successful.FAULT (amber) lightindicates a fault withinIDG (low oil pressure orhigh oil temperature).ACUsed to select externalAC power.AVAIL (green) lightindicates externalpower is connectedand is ready to use.IN USE (white) lightindicates that theexternal AC power unitis supplying theelectrical system.ONIDG will automaticallydisconnect, when anovertemperature orovertorque conditionoccurs.Once disconnected, theIDG cannot be reset withthe engines running.Electrical Power PanelOverhead PanelAUTO XFERUsed to disable automatictransfer of associated IDG.OFF (white) light indicatesautotransfer is selected off.FAIL (amber) light indicates afault preventing autotransfer.EXT AC PUSHUsed to selectexternal AC power.AVAIL (green) lightindicates externalpower is connectedand is ready to use.IN USE (white) lightindicates that theexternal AC powerunit is supplying theelectrical system.External Service PanelRight Forward Fuselage & (OHFWULFDO 6\VWHP)LJXUH Page 8GEN 1, 2 and APU GENAUTO -- Connectsgenerator toassociated bus.OFF/RESET -Disconnects generatorfrom associated busand/or resets thegenerator controlcircuit.

Canadair Regional Jet 100/200 - ElectricalFlow LinesGreen -- Bus energized.Blank -- Bus not energized.Generator LoadDisplays the load onthe generator.Generator VoltageDisplays the generatorvoltage level.Generator FrequencyDisplays the generatorfrequency level.AC Electrical PageEICAS DIGITALREADOUTXX KVAXXX VXXX HZGREENAMBERWHITEGeneratorloadedVoltage100--125 VACFrequency375--425 HzGeneratoroverloadGenerator notloadedVoltage notin rangeFrequencynot in rangeHALF INTENSITYAMBER DASHESMAGENTAInvalid dataInvalid dataInvalid dataEICASOUTLINEGREENAMBERGENGenerator onGenerator offwith engine /APU runningBoth generatorand engine /APU are offInvalid dataIDGConstantspeed drive onLow oil pressureor high oiltemperatureEngine is off orIDG hasdisconnectedInvalid dataEngine / APU offInvalid dataBus not poweredInvalid dataBus not poweredInvalid dataInvalid dataInvalid dataAPUBUS 1BUS 2Bus powered(generator linecontactor 1)Bus powered(generator linecontactor 2)ESS BUSBus poweredSERV BUSBus poweredUTIL BUS 1Bus poweredUTIL BUS 2Bus poweredBus inoperative(essential busfail)Bus inoperative(AC service busfail)WHITEBus not powered(shed)Bus not powered(shed)HALF INTENSITY HALF INTENSITYMAGENTACYANInvalid dataInvalid data & (OHFWULFDO 6\VWHP 6\QRSWLF 3DJH)LJXUH 6KHHW Page 9Engine / APUrunning andready to load

Canadair Regional Jet 100/200 - ElectricalADG FeaturesDisplayed when ADG voltage is more than 10 voltsand frequency is more than 300 Hz.SHED (white)Indicates that the respective AC utilitybus has been automatically shed.AUTO XFER OFF (white)Indicates that corresponding automatictransfer has been selected off.AUTO XFER FAIL (amber)Indicates that corresponding automatictransfer has failed.AC Electrical PageDISC (white)Indicates that IDG has been disconnected.EICAS DIGITALREADOUTLess than 108 volts ormore than 130 voltsLess than 360 Hz ormore than 440 HzBetween 108 and130 voltsBetween 360 and440 HzXXX VXXX HZEICASOUTLINEAMBER DASHESWHITEGREENGREENInvalid dataInvalid dataWHITEADG BUSADG outline greenADG outline whiteADGVoltage and frequencydigital readouts greenVoltage or frequencydigital readouts white & (OHFWULFDO 6\VWHP 6\QRSWLF 3DJH)LJXUH 6KHHW Page 10

Canadair Regional Jet 100/200 - ElectricalSERVICE CONFIGURATION (green)The message is displayed:When external AC power is available and theAVAIL switchlight on the external service panelhas been selected, orWhen APU power is available and the APUSERV BUS switchlight on the forward F/Apanel has been selected.For either selection, only the AC service bus, ACutility bus 1, AC utility bus 2, and the DC servicebus will be powered.External AC Power FeaturesDisplayed when external AC voltage is morethan 10 volts and frequency is more than 50 Hz.AC Electrical PageEICAS DIGITALREADOUTGREENAMBERWHITEXX KVALoadedOverloadNot loadedInsufficient dataBetween 106and 124 voltsBetween 370and 430 HzLess than 106 volts ormore than 124 voltsLess than 370 Hz ormore than 430 HzXXX VXXX HZEICASOUTLINEGREENHALF INTENSITY AMBER DASHESMAGENTAWHITEExternal AC available External AC not availableor in useand not in use & (OHFWULFDO 6\VWHP 6\QRSWLF 3DJH)LJXUH 6KHHW Page 11Invalid dataInvalid dataInvalid dataHALF INTENSITYMAGENTAInvalid data

Canadair Regional Jet 100/200 - Electrical 0006 0039 IDG 1 or 2 caution (amber)Indicates that IDG has low oil pressureor high oil temperature.GEN 1 or 2 OFF caution (amber)Indicates that generator is off.(Indications are inhibited during start)GEN 1 or 2 OVLD caution (amber)Indicates that generator control unit hasdetected a load of greater than 40 kVA.APU GEN OFF caution (amber)Indicates that APU generator is off andAPU is ready to load.APU GEN OVLD caution (amber)Indicates that generator control unit hasdetected a load of greater than 40 kVA.Primary PageIDG 1 or 2 DISC status (white)Indicates that IDG has been disconnected,either automatically or manually. 0039 0039 Status Page & (OHFWULFDO 6\VWHP (,& 6 ,QGLFDWLRQ *HQHUDWRUV MST)LJXUH Page 12

Canadair Regional Jet 100/200 - Electrical 0006 0039 EMER PWR ONLY warning (red)Indicates that the ADG has deployed.AC BUS 1 or 2 caution (amber)Indicates that the associated bus is notpowered.AC ESS BUS caution (amber)Indicates that AC essential bus isless than 90 Volts.AC SERV BUS caution (amber)Indicates that AC bus 2 is powered andAC service bus is less than 90 Volts.AC 1 or 2 AUTOXFER caution (amber)Indicates that the corresponding automaticbus transfer has failed.Primary PageAC 1 or 2 AUTOXFER OFF status (white)Indicates that the corresponding automaticbus transfer has been selected off. 0039 AC ESS ALTN status (white)Indicates that AC essential bus isbeing fed from AC bus 2. 0039 AC UTIL 1 or 2 OFF status (white)Indicates that corresponding ACutility bus is not powered.Status Page & (OHFWULFDO 6\VWHP (,& 6 ,QGLFDWLRQV %XVVHV MST )LJXUH Page 13

Canadair Regional Jet 100/200 - ElectricalAC BUS to TRU FlowLinesGreen -- RespectiveAC bus is poweringTRU.TRU Voltage ReadoutsDisplays, in incrementsof 1 VDC, the rectifier’svoltage level.TRU Output FlowLinesGreen -- RespectiveTRU is on--line andoutput is 18 VDC orgreater.TRU Load ReadoutsDisplays, in incrementsof 1 amp, the load onthe rectifier.DC ELEC PageEICAS Secondary DisplayCenter Instrument PanelEICAS DIGITALREADOUTGREENxx VBetween 22 and 29 VDCxx ABetween 3 and 99 ampEICASOUTLINETRU 1AMBER DASHESLess than 22 VDC ormore than 29 VDCLess than 3 amp ormore than 99 ampInvalid dataHALF--INTENSITYMAGENTAWHITETRU118 VDC or greaterLess than 18 VDCInvalid dataTRU 218 VDC or greaterLess than 18 VDCInvalid dataVAServiceTRU18 VDC or greaterLoad more than2 ampVAEssentialTRU 2VAEssentialTRU 1Less than 18 VDCLoad less than2 ampLess than 18 VDCLoad less than3 ampLess than 18 VDCLoad less than3 ampVVAMBERInvalid dataGREENATRU 2WHITEASERVTRU 2EssTRU 2EssTRU 118 VDC or greaterLoad more than3 amp18 VDC or greaterLoad more than3 ampTRU failureInvalid dataTRU failureInvalid data7UDQVIRUPHU 5HFWLILHU 8QLWV)LJXUH Page 14Invalid data

Canadair Regional Jet 100/200 - ElectricalThe AC essential bus is normally powered by AC bus 1. ,I D IDXOW H[LVWV RQ & EXV WKH *&8 ZLOO DXWRPDWLFDOO\ WUDQVIHU WKH SRZHU VXSSOLHG WR WKH & HVVHQWLDO EXV IURP &EXV WR & EXV The crew can also manually transfer the & HVVHQWLDO EXV VXSSO\SRZHU IURP & EXV WR & EXV XVLQJ WKH & (66 ;)(5 VZLWFKOLJKW RQ WKH HOHFWULFDOSDQHO. In flight, the AC service bus is normally powered from AC bus 2. On the ground,it can be powered from the APU generator or from external AC power.The AC service bus supplies power to those circuits necessary for ground--servicingoperations, without having to power the entire electrical system.The AC utility buses are normally powered (in full configuration) by their respective ACbus. In flight, the AC utility buses are automatically SHED if only one generator isoperational. In service configuration, the AC utility buses are powered from either theAPU generator or from external AC power.D.AC Loads DistributionAC BUS 1AC BUS 2AC ESSENTIALHydraulic Pumps 2B and 3BLeft Windshield HeaterProbe Heaters (R) (AOA andPitot) and TATLeft --Navigation, Landing andTaxi LightsGround Proximity WarningSystem (GPWS)Enhanced Ground ProximityWarning System (EGPWS)HSTA (Ch--1)Hydraulic Pumps 3A and 1BRight Windshield HeatersRight Window HeaterIce Detector 2Instrument Lights (copilot andoverhead), Landing and TaxiLights (R)Inertial Reference System (2) 0040 ARINC Display Fan, Galleyand Cabin FanFlap Power Drive Unit (2)ADG Deploy SensorTRU 2, DC Essential busHSTA (Ch--2)Bleed Leak Controllers (L / R)Left Window HeaterProbe Heaters (L) (AOA andPitot)Ice Detector 1Engine Ignition AInstrument Lights (Pilot’s andCenter)CB Panel Integral LightsInertial Reference System (1)Flight Recorder PowerHydraulic System FanDisplay Cooling Fan (R)Exhaust and Cockpit FanFlap Power Drive Unit (1)Engine Vibration MonitorADG Deploy SensorTRU 1, DC essential bus 0025 & 87,/,7 %86 & 87,/,7 %86 *DOOH\ DQG&RHH 0DNHUD H&RIIHH0DLQ %DWWHU\J&KDUJHU3RZHU 6HQVLQJ5HOD\*DOOH\ DQGDWH 6\VWH:DWHU6\VWHP 38 %DWWHU\J&KDUJHU3RZHU 6HQVLQJ5HOD\Page 15 & 6(59,&(%866HUYLFH 7589DFXXP &OHDQHU7RLOHW0RWRU SXPS 0025 Head--up Guidance System 0026 Traffic Alert and CollisionAvoidance (TCAS)ARINC Chassis and DisplayCooling Fans (L)Essential TRU 1 '* %XV \GUDXOLF 3XPS %)ODSV

Canadair Regional Jet 100/200 - ElectricalE.Air Driven Generator (ADG)In the event of a complete AC power failure in flight, the ADG will automatically deployand supply 115--volts, 400 Hz AC emergency power to the ADG bus. The ADGgenerator is rated at 15 KVA. The ADG bus will then supply emergency power to theAC essential bus and the 3B hydraulic pump. The AC essential bus will then poweressential TRU 1, which will power the DC essential bus.If the automatic deploy function fails, the ADG can be deployed manually by pulling theADG manual release handle on the ADG CONTROL control panel at the rear of thecenter console.If either main generator is restored, the crew can override the ADG by pressing thePWR TXFR OVERRIDE button on the ADG control panel. This will reconnect therestored IDG to power AC bus 1, AC bus 2 and the AC essential bus. The ADG willcontinue to power the critical flight controls and the ADG bus. The flaps will move athalf speed when powered from the ADG bus.The ADG generator, voltage, frequency and ADG bus indications on the EICAS, ACELECTRICAL synoptic page are only displayed when the ADG bus is powered.The ADG will continue to operate and supply power to the ADG bus until the airspeeddecreases below approximately100 kts. At that point, if the APU generator or IDG hasnot been restored, the only power available will be from the batteries.The ADG cannot be restowed in flight. It is restowed manually, on the ground, bymaintenance personnel.NOTEAfter ADG deployment or APU generator switching,intermittent failure of the pilot’s and copilot’s air datasystems may occur. These failures may result inuncommanded changes to the pilot’s or copilot’s flightinstruments. The barometric altimeter setting, altitudepreselector, V--speeds and speed bug settings shouldbe checked and reset as required.Automatic deployment of the ADG is inhibited, on the ground, when the parking brakeis set.The ADG system circuits can be checked through a LAMP/UNIT test switch on the ADGcontrol panel. When the switch is set to LAMP, a ground is supplied to check that thegreen TEST light illuminates. The UNIT test has two modes, Pre--takeoff and Inflight:: Pre--takeoff,When the test switch is set to UNIT the ADG system circuits are checked and theTEST light will illuminate within 1 second and remain ON for 2 seconds.: Inflight,When the test switch is set to UNIT the ADG system circuits are checked and theTEST light will illuminate after 5 seconds and remain ON for 2 seconds.Page 16

Canadair Regional Jet 100/200 - ElectricalLAMP/UNIT SwitchUsed to test auto--deploy system.Test can only be accomplished withtwo generators selected ON andboth main AC busses powered.ADG Manual Deploy HandleUsed to manually deploy the ADG.TEST Light (green)Comes on after successfulcompletion of auto--deploysystem test.ADG Manual Deploy Handleand Auto--Deploy PanelCenter Pedestal LU 'ULYHQ *HQHUDWRU '*)LJXUH Page 17PWR TXFR OVERRIDEUsed to transfer ACessential bus power sourcefrom the ADG bus back tothe main AC bus.


Canadair Regional Jet 100/200 - Electrical1.DC ELECTRICAL SYSTEMFive transformer rectifier units (TRU’s) and two batteries (Main and APU) provide the aircraftwith DC electrical power. DC power is also available through an external DC receptacle onthe right aft fuselage.A.Transformer Rectifier Units (TRU)There are five TRU’s located in the nose avionics compartment. Each TRU converts115 VAC input power to 28 VDC output power for powering the aircraft DC buses. TheTRU’s are rated at 100 amps. Normal distribution of the TRU outputs is shown in thefollowing table:,1387 %86758287387 %86 & %XV 758 '& %XV DQG'& 8WLOLW\ %XV 758 '& %XV DQG'& 8WLOLW\ %XV (VVHQWLDO 758 '& (VVHQWLDO %XV DQG%DWWHU\ %XV & 6HUYLFH %XV6HUYLFH 758'& 6HUYLFH %XV & (VVHQWLDO %XV(VVHQWLDO 758 '& (VVHQWLDO %XV DQG%DWWHU\ %XV & %%XV B.BatteriesThe main and APU nickel-cadmium batteries and their battery chargers are located inthe aft equipment compartment. The batteries provide DC power to their respective DCbattery direct buses.The 17 AMP./HR, 24, volt main battery provides backup power to the attitude headingreference system (AHRS), proximity sensing electronic unit (PSEU), data concentratorunits (DCU’s), aircraft clocks, and the APU electronic control unit (ECU). The mainbattery also provides power to the flight compartment lighting system.The 17 AMP./HR, 24 volt, main battery provides backup power to the inertial referencesystem (IRS), proximity sensing electronic unit (PSEU), data concentrator units(DCU’s), aircraft clocks, and the APU electronic control unit (ECU). The main batteryalso provides power to the flight compartment lighting system. 0025 The 43 AMP./HR, 24 volt, APU battery provides the cranking power for starting theAPU.Page 19

Canadair Regional Jet 100/200 - ElectricalBattery chargers maintain the batteries at full charge. The main battery charger ispowered from AC Utility bus 1 and the APU battery charger is powered from the ACUtility bus 2. Battery charging is controlled automatically. Each charger monitors thebattery voltage and temperature to control the battery charge rate. If a battery reachesthe overtemperature set point (as sensed by the charger), the charging will stop toprevent overheating (thermal runaway).Effectivity:: Airplanes 7001 to 7220NOTEIn flight, both chargers will be shed during singlegenerator operations. On the ground, both chargers areshed if external AC power is connected and the flaps areout of the 0 detent, and the passenger door is closed.Effectivity::Aircraft 7221 and subsequentNOTEIn flight, both chargers will be shed during singlegenerator operations. On the ground, both chargers areshed if external AC power is connected, the flaps are outof the 0 detent, and the passenger and service doors areclosed.Page 20

Canadair Regional Jet 100/200 - Electrical'& 'LVWULEXWLRQ 6\VWHP)LJXUH Page 21

Canadair Regional Jet 100/200 - ElectricalBATTERY MASTERUsed to connect the APUand main battery directbusses to the battery bus.DC SERVICEUsed to connect the DCservice bus to the APUbattery direct bus.NOTEBattery master shouldalways be in the ONposition in flight.BUS TIE 1 or 2Switch/LightsCLOSED -- Come onwhite to indicate thatthe corresponding DCbus has beenautomatically tied tothe service TRU duringan abnormalcondition, or has beenpressed in, to manuallytie corresponding busto the service TRU.Essential Bus TieSwitch/LightCLOSED -- Whenpressed in, comeson white to indicatethat ESS Bus hasbeen manually tiedto the service TRUduring a DCessential TRU failure.CLOSED light (white)comes on.Corresponding utilitybus is shed whenswitch/light indicatesCLOSED.ESS TIE switch/lightcan only be selectedmanually.Electrical Power PanelOverhead Panel'& (OHFWULFDO 6\VWHP)LJXUH Page 22

Canadair Regional Jet 100/200 - ElectricalC.([WHUQDO '& 3RZHUThe aircraft can be connected to 28 volts DC from an external receptacle located on theright aft fuselage below No. 2 engine. External DC is used for ground operations tosave battery power and can be used to start the APU. When external DC is connectedto the aircraft, an external DC contactor is energized to provide power to the APU startcontactor. At the same time, the AVAIL lamp in the DC switchlight illuminates. Pressingthe switchlight closes two contactors to connect the external DC to the Main and APUbattery direct buses and the IN USE lamp in the switchlight illuminates.D.DC DistributionDC power is distributed to the DC system by five TRU’s. DC bus 1 and DC Utility bus 1are powered from TRU 1. DC bus 2 and DC Utility bus 2 are powered from TRU 2.The DC essential bus and battery buses are normally powered from the essentialTRUs. The emergency bus is powered from the battery bus and the APU battery directbus. The service TRU powers the DC service bus. In the event that an essential TRUfails, the DC essential bus and battery bus will remain powered from the operatingessential TRU. If both essential TRU’s fail, the essential DC bus and battery bus maystill be powered from the service TRU by selecting the ESS TIE switchlight on theelectrical panel. In the event that a main TRU fails, the respective DC tie will close tomaintain power to the respective DC bus 1/2 from the service TRU. At the same timethe corresponding utility bus will be SHED.The Main battery direct bus, APU battery direct bus, and the emergency bus are all hotbuses (they are continuously powered at all times from the batteries). When theBATTERY MASTER switch is selected ON, an input signal is supplied to the two powercontrollers (PC). The power controllers monitor for AC power, and if AC power is notavailable then the controllers will connect their respective batteries to the battery bus.When AC power is available, for the TRU’s to power the DC system, the powercontrollers will disconnect the batteries from the battery bus. Each battery direct buscan power the DC battery bus. Both the battery bus and the APU battery direct buspower the DC emergency bus. The DC service bus is normally powered from theservice TRU. If the DC SERVICE switch on the electrical panel is selected ON, the DCservice bus will be powered from the APU battery direct bus.NOTEAlthough there is only one battery bus, it is splitbetween circuit breaker panel 1 and 2 and is referredto as the left and right battery bus.In flight, if the power controllers sense a complete loss of AC power, they will reconnectthe batteries to the battery bus and at the same time the DC emergency ties will closeto connect the battery bus to the DC essential bus. Once the ADG bus is online topower essential TRU 1 and the DC essential bus, the batteries will act as a backuppower source to the DC essential bus.Page 23

Canadair Regional Jet 100/200 - Electrical 0006 0039 Primary Page 0039 0039 Status Page'& (OHFWULFDO 6\VWHP (,& 6 ,QGLFDWLRQV MST )LJXUH Page 24

Canadair Regional Jet 100/200 - ElectricalDC Emergency Bus FlowLinesGreen -- DC emergencybus is powered throughthe respective flow lineonly, or the respectivefeeder bus is availableto feed the failed DCemergency bus.White -- DC emergencybus is not poweredthrough the respectiveflow line.CHARGER (White) 0039 CHARGER (Amber)Indicates that thecorresponding chargeris not charging.NOTEDuring normal operation,when the DC emergencybus is powered by both thebattery bus and the APUbattery direct bus, the DCemergency bus outline andrespective flow lines are notdisplayed.EICAS BUS BAROUTLINEBUS 1BUS 2UTIL BUS 1UTIL BUS 2DC ELEC PageEICAS DisplayCenter Instrument PanelGREENAMBERBus poweredBus not poweredBus poweredInvalid dataInvalid dataBus not poweredInvalid dataBattery 18 VDCor greaterBattery lessthan 18 VDCBattery 18 VDCor greaterBattery lessthan 18 VDCBATT BUSBus poweredBus not poweredSERV BUSBus poweredAPU BATTDIR BUSMAIN BATTDIR BUSVABus not poweredInvalid dataBus not poweredMAINBATTHALF--INTENSITYMAGENTAInvalid dataBus poweredAPUBATTWHITEESS BUSEICAS BUS BAROUTLINEDC Emergency BusOutlineGreen -- DC emergencybus is powered by onlyone of the following:Battery bus or,APU battery direct bus.Amber -- DC emergencybus is not poweredWHITEGREENBattery 18 VDCor greaterExternal dc in useAlways displayedbetween 18V & 32V.Less that 18V orgreater than 32V.AMBERBattery lessthan 18 VDC'& (PHUJHQF\ %XV MST )LJXUH Page 25Invalid dataInvalid dataHALF-

components. Power connection is dependent on system configuration and health. The following is a list of all the aircraft electrical system buses: AC BUSSES DC BUSSES DC BUS 1 AC BUS 1 DC BUS 2 DC ESSENTIAL BUS ACBUS2 DC ESSENTI LBUS DC SERVICE BUS C BUS 2 AC ESSENTIAL BUS DC SERVICE BUS LEFT AND RIGHT BATTERY BUS AC SERVICE BUS DC EMERGENCY .