atr electrical system push button description

8/6/2019 ATR Electrical System Push Button Description

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FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHED

OFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

Let’s examine the electricalLet’s examine the electricalpanel and the componentspanel and the componentsof the electrical system.of the electrical system.

FAULT

OFF

The DC Generator Control The DC Generator Control push button

push button : selects or: selects orde-selects the generator.de-selects the generator.

TheThe FAULTFAULT light will illuminate ambelight will illuminate ambeif the Generator Control Unit sensesif the Generator Control Unit sensesa protection fault and trips thea protection fault and trips thegenerator off-line for:generator off-line for:

1. Over/Under voltage1. Over/Under voltage2. Under-speed2. Under-speed

3. Generator Overload3. Generator Overload

4. Sensing a differential fault curren4. Sensing a differential fault curren

For a fault associated with an under-speeFor a fault associated with an under-speereset will be automatic if Nh increasesreset will be automatic if Nh increasesto above 61.5%.to above 61.5%.

For anything else, a manual reset isFor anything else, a manual reset isnecessary. ON then OFF.necessary. ON then OFF.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHED

OFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

EMERGENCY SUPPLY ARROW EMERGENCY SUPPLY ARROW

The left and right amber arrows illuminThe left and right amber arrows illuminany time the Emergency and Mainany time the Emergency and Mainbatteries respectively are isolated frombatteries respectively are isolated fromthe charging cycle.the charging cycle.

Both arrows will illuminate at theBoth arrows will illuminate at theinitiation of a start cycle and willinitiation of a start cycle and willextinguish at 45% Nh. This denotesextinguish at 45% Nh. This denotesisolation and protection during the starisolation and protection during the starcycle.cycle.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHED

OFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

DC SVCE/UTLY BUS:DC SVCE/UTLY BUS:The DC SVCE/UTLY bus push buttonThe DC SVCE/UTLY bus push buttoncontrols the utility and service buses.controls the utility and service buses.The amberThe amber SHEDSHED light will illuminatelight will illuminatewhen either of the utility buses havewhen either of the utility buses havebeen shed it does not monitor thebeen shed it does not monitor thestatus of the Service bus..status of the Service bus..

SHED

OFFSHED

** When the Service Bus is being powerWhen the Service Bus is being powerfrom DC Bus #1, the master switch isfrom DC Bus #1, the master switch isthe DC SVCE/UTLY push button.the DC SVCE/UTLY push button.

** When the Service Bus is being powerWhen the Service Bus is being powerfrom external power, the master switcfrom external power, the master switcis on the flight attendant panel.is on the flight attendant panel.

If de-selected, theIf de-selected, the OFFOFF light willlight willilluminate.illuminate.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHED

OFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

DC SVCE/UTLY BUS:DC SVCE/UTLY BUS:The DC SVCE/UTLY bus push buttonThe DC SVCE/UTLY bus push buttoncontrols the utility and service buses.controls the utility and service buses.The amberThe amber SHEDSHED light will illuminatelight will illuminatewhen either of the utility buses havewhen either of the utility buses havebeen shed it does not monitor thebeen shed it does not monitor thestatus of the Service bus..status of the Service bus..

SHED

OFFSHED

** A clue to determine which utility busA clue to determine which utility busis shed, is by checking the recirculatiois shed, is by checking the recirculatiofans. The fan that is not runningfans. The fan that is not running

indicates the shed bus.indicates the shed bus.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHED

OFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

DC BUSOFFDC Bus OFF light:DC Bus OFF lig

ht:The DC BUS OFF light will illuminateThe DC BUS OFF light will illuminatewhen power to the associated DCwhen power to the associated DCBus is lost.Bus is lost.

When DC Bus #2 Fails, a single chimeWhen DC Bus #2 Fails, a single chimesounds with an associated ambersounds with an associated amber ELECELEClight on the Crew Alerting Panel (CAP).light on the Crew Alerting Panel (CAP).

Additional lights including:Additional lights including:

Inverter FaultInverter Fault

BUSOFF INVFAULT

FAULTDC GeneratorDC Generator FAULTFAULT

DC SVCE/UTLY BusDC SVCE/UTLY Bus SHEDSHED

SHED

SHED

ENG 2FIRE

ENG 1FI RE

CONFIGEXCESSCAB ALT

LDG GEARNOT DOWN

ENG 2 OILENG 1 OIL

NAC OVHTFLAPS UNLK

AFT SMK FWD SMK ELEC SMK

PROP BRK

OXY LOOPHYD

AIRANTI I CINGFUEL

ELECENGDOOR

FLT CTLWHEELSAUDIO

EFIS COMPGPWS FAULTI DLE GATE

MAINT PNLCCASPRKG BRK

RCL CLR TO

PITCH

DI SCONNECT

INHI



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

X START FAIL light: X START FAIL lig ht:The X START FAIL light will illuminateThe X START FAIL light will illuminateduring the start cycle.during the start cycle.

** When the second engine is beingWhen the second engine is beingstarted, at 10% Nh, the operatingstarted, at 10% Nh, the operatinggenerator will be connected to the stargenerator will be connected to the starbus via its start contactor. Thisbus via its start contactor. Thisconnection will assist the battery in theconnection will assist the battery in thestart process and will continue untilstart process and will continue untilthe completion of the start cyclethe completion of the start cycle(45% Nh).(45% Nh).

** If the generator does not assist in theIf the generator does not assist in thestart process, a single chime will bestart process, a single chime will beheard and an amberheard and an amber ELECELEC light willlight willilluminate on the CAP.illuminate on the CAP.

X STARTFAIL

ENG 2FIRE

ENG 1FI RE

CONFIGEXCESSCAB ALT

LDG GEARNOT DOWN

ENG 2 OILENG 1 OIL

NAC OVHTFLAPS UNLK


PROP BRK

OXY LOOPHYD

AIRANTI I CINGFUEL

ELECENGDOOR

FLT CTLWHEELSAUDIO



RCL CLR TO

PITCH

DI SCONNECT

INHI



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

X START FAIL light: X START FAIL lig ht:The X START FAIL light along withThe X START FAIL light along withthe CCAS alert will extinguishthe CCAS alert will extinguishat the completion of the start cycle.at the completion of the start cycle.

X STARTFAIL

ENG 2FIRE

ENG 1FI RE

CONFIGEXCESSCAB ALT

LDG GEARNOT DOWN

ENG 2 OILENG 1 OIL

NAC OVHTFLAPS UNLK


PROP BRK

OXY LOOPHYD

AIRANTI I CINGFUEL

ELECENGDOOR

FLT CTLWHEELSAUDIO



RCL CLR TO

PITCH

DI SCONNECT

INHI

92.345.0

6080

100

40

20

0%

Nh



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

EXTERNAL POWER:EXTERNAL POWER:The Bus Protection Control Unit provideThe Bus Protection Control Unit providefor the following:for the following:

AVAILON

1. Undervoltage (< 24.5 v)1. Undervoltage (< 24.5 v)

2. Overvoltage (> 33.5 v)2. Overvoltage (> 33.5 v)

3. Correct Polarity3. Correct Polarity(Negative Common Ground)(Negative Common Ground)

4. Excessive Current (> 1450 Amps4. Excessive Current (> 1450 Ampsduring the start.during the start.

If the BPCU checks the external powerIf the BPCU checks the external powerand finds it acceptable, then a greenand finds it acceptable, then a greenAVAIL light is illuminated.AVAIL light is illuminated.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

EXTERNAL POWER:EXTERNAL POWER:

AVAILON

When the push button is depressed andWhen the push button is depressed andcommanded on, a bluecommanded on, a blue ONON light willlight willappear.appear.

Things To Remember:Thing s To Remember:The Battery Switch must be selectedThe Battery Switch must be selectedon in order for the BPCU to operate.on in order for the BPCU to operate.This means that a dead battery can notThis means that a dead battery can notbe charged from the GPU.be charged from the GPU.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

Things To Remember:Thing s To Remember:The Ground Power Unit (GPU) must beThe Ground Power Unit (GPU) must becapable of providing a constant currentcapable of providing a constant currentrating of rating of 300 to 400 amps at 28 to 32300 to 400 amps at 28 to 32voltsvolts ..

During the start, the GPU must be ableDuring the start, the GPU must be ableto provide for anto provide for an additional 1000 ampsadditional 1000 amps

while always maintaining awhile always maintaining a minimum of minimum of 12 volts12 volts ..Prior to selecting the external power “OPrior to selecting the external power “Ocheck the current and amps on thecheck the current and amps on thegauges located on the Captain’s Maint.gauges located on the Captain’s Maint.Panel. If the rating is below 28 volts, thPanel. If the rating is below 28 volts, ththe following equipment should bethe following equipment should beselected off.selected off.

Pack Valves 120 amp reductiPack Valves 120 amp reductiFuel Pumps 20 amp reductiFuel Pumps 20 amp reductiRecirc Fans 32 amp reductiRecirc Fans 32 amp reductiUpper Pass. Lighting 23 amp reductioUpper Pass. Lighting 23 amp reductio



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

Things To Remember:Thing s To Remember:

If the GPU indicates at least 26 volts, thIf the GPU indicates at least 26 volts, thGPU can be used for all functions exceptGPU can be used for all functions exceptstarting.starting.

The GPU should be selected “OFF” priorThe GPU should be selected “OFF” priorto starting, otherwise the External Poweto starting, otherwise the External Powe

Contactor (EPC) will open automaticallyContactor (EPC) will open automaticallyduring the start.during the start.

** If the GPU voltage is less than 26 voltsIf the GPU voltage is less than 26 voltsthe GPU is not usable for any purpose.the GPU is not usable for any purpose.

Clue for line flying:Clue for line fly ing:If the supply arrows are flashing andIf the supply arrows are flashing andyou hear relays clicking. Check theyou hear relays clicking. Check thevoltage and have ground personnel turvoltage and have ground personnel turup the voltage of the GPU.up the voltage of the GPU.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

The Bus Tie Contactor:The Bus Tie Contactor:

The Bus Tie Contactor switch controls thThe Bus Tie Contactor switch controls thmanual isolation of both AC and DCmanual isolation of both AC and DCBus Tie Relays.Bus Tie Relays.

The Bus Tie Relay functions to provideThe Bus Tie Relay functions to providepower to both sides of the electricalpower to both sides of the electricalsystem in the event of failure of onesystem in the event of failure of oneDC Generator or during groundDC Generator or during groundoperations where power is being supplieoperations where power is being supplieby the GPU.by the GPU.

SHED

ISOL

The Bus Tie Relays are independent forThe Bus Tie Relays are independent forboth AC and DC systems. They are freeboth AC and DC systems. They are freeto operate separately but can both beto operate separately but can both becommanded open from a commoncommanded open from a commonisolation push button.isolation push button.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON


To Manually isolate the BTR so that itTo Manually isolate the BTR so that itis incapable of operating, the switchis incapable of operating, the switchmust be depressed.must be depressed.

SHED

ISOL

When the switch is depressed, a whiteWhen the switch is depressed, a whiteISOL light will illuminate. This willISOL light will illuminate. This willmanually isolate both AC and DCmanually isolate both AC and DCBus Tie Relays.Bus Tie Relays.

The BPCU switching logic will determineThe BPCU switching logic will determinewhen and if the BTR will close and supplwhen and if the BTR will close and supplpower to the electrical system.power to the electrical system.

Normal switch position is push buttonNormal switch position is push button““ OUT”.OUT”.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON


SHED

A Green Flow Bar is illuminated whenA Green Flow Bar is illuminated whenthe BTR is closed and power is beingthe BTR is closed and power is beingdelivered across the contactor.delivered across the contactor.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

The Battery Protection Unit:The Battery Protection Unit:The BPU operates to isolate the hotThe BPU operates to isolate the hotbattery bus from the associated DCbattery bus from the associated DCBattery Bus.Battery Bus.

It automatically opens the Battery CharIt automatically opens the Battery CharContactor (BCC) in any of the followingContactor (BCC) in any of the following

situations.situations.1. Thermal Runaway1. Thermal Runaway

(excessive current increase)(excessive current increase)

2. When the Engine Start Selector is2. When the Engine Start Selector isturned to initiate a start sequence.turned to initiate a start sequence.

3. Undervoltage of a main DC Bus3. Undervoltage of a main DC Bus(<25 volts)(<25 volts)

4. BAT toggle switch placed in OVRD.4. BAT toggle switch placed in OVRD.



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

The Battery Protection Unit:The Battery Protection Unit:The BCC willThe BCC will FAULTFAULT for any of thefor any of thefollowing reasons.following reasons.

1. Battery Overheat (71 C)1. Battery Overheat (71 C)

2. Excess Battery Charge Current/2. Excess Battery Charge Current/Failure of the Charge ControlFailure of the Charge ControlSystem.System.(150 amps for 90 or more seconds)(150 amps for 90 or more seconds)

3. A failure of the BCC to operate.3. A failure of the BCC to operate.

FAULT



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

Battery Amperage Indicator:Battery Amperage Indicator:The Bat Amp Indicator shows charge (CThe Bat Amp Indicator shows charge (Cor discharge (DCH) of the selectedor discharge (DCH) of the selectedbattery by switching of the toggle switcbattery by switching of the toggle switc

The scale is numbered in reference toThe scale is numbered in reference toamps x 100.amps x 100.

MAIN

01

2

1

2 DC

CHDCH

BAT SEL

EMERG



FAULT

OFF

FAULT

OFF

AVAILX START

FAIL

SHEDOFF

SHED

SHED

ISOL

DC GEN 2DC GEN 1

01

2

1

2DC

CHDCH

DC SVCE/UTLY BUS

BAT SEL

MAINEMERG BTC

DC BUSOFF

DC BUSOFF

BUSOFF

INVFAULT

BUSOFF

INVFAULT

EXT PWR

EMER BATCHG

EMER BUS

OVRD

UND/V

ESS BUS

FAULT

OFF

FAULT

OFF

STBY BUS

AC BUS 2AC BUS 1

INV 1

DC BUS 1

OFF

ON

OVRD

BAT

MAIN BATCHG

INV 2

DC BUS 2

ON

Stand-by Bus and Inverter 1 OVRD:Stand-by Bus and Inverter 1 OVRD:This guarded switch is used whenThis guarded switch is used whenoperating in battery only mode. The maoperating in battery only mode. The mabattery will be supplying power to thebattery will be supplying power to theDC Essential Bus, DC Stand-by Bus andDC Essential Bus, DC Stand-by Bus andthe AC Stand-by Bus through Inverter #the AC Stand-by Bus through Inverter #

When the voltage sensed across theWhen the voltage sensed across theDC Stand-by bus is 19.5 volts, theDC Stand-by bus is 19.5 volts, theamber Undervoltageamber Undervoltage (UND/V)(UND/V) light willlight willilluminateilluminate

OVRD

UND/V

The override switch must then be pressThe override switch must then be pressswitching the DC Stand-by Bus andswitching the DC Stand-by Bus andInverter #1 to the Emergency Battery.Inverter #1 to the Emergency Battery.

** Switching must be accomplished priorSwitching must be accomplished priorto depleting the main battery belowto depleting the main battery below

18 volts.18 volts.



Bus Power Control Unit:Bus Power Control Unit:

The Bus Power Control Unit is the switching logic that operates withiThe Bus Power Control Unit is the switching logic that operates withithe electrical system. Two independent BPCUs control the AC and DCthe electrical system. Two independent BPCUs control the AC and DCsystems, one for each system.systems, one for each system.

The BPCU can be powered by:The BPCU can be powered by:

1. DC External Power1. DC External Power

2. DC Emergency Bus2. DC Emergency Bus

3. GCU #1 or #2 (provided the generators are operating)3. GCU #1 or #2 (provided the generators are operating)



Bus Power Control Unit:Bus Power Control Unit:

If for any reason, the BPCU should fail, the result will be an opening oIf for any reason, the BPCU should fail, the result will be an opening othe Bus Tie Contactor (BTC) and a closure of the Battery Startthe Bus Tie Contactor (BTC) and a closure of the Battery StartContactor (BSC).Contactor (BSC).

Normal electrical operation will not be affected with the failure.Normal electrical operation will not be affected with the failure.In addition, in-flight engine starting will remain unaffected. No otherIn addition, in-flight engine starting will remain unaffected. No othernormal system functions will be available.normal system functions will be available.

In other words nothing will be effected until a failure is experienced.In other words nothing will be effected until a failure is experienced.However, no automatic corrective actions will take place.However, no automatic corrective actions will take place.

Note:Note:

atr electrical system push button description

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