Boeing 737NG - Electrical - SmartCockpit - Airline training guides, Aviation, Operations, Safety

Either generator or the APU can power both transfer buses. In the event a power source fails, what is required for that transfer bus to be powered by the opposite transfer bus power source?

The generator switch must be OFF.

The battery switch must be ON.

The battery switch must be OFF.

The BUS TRANS switch must be in the AUTO position.

Correct! Wrong!

Each IDG supplies its own bus system in normal operation and can also supply essential and non-essential loads of the opposite side bus system when one IDG is inoperative.

False.

True.

Correct! Wrong!

Galley busses are powered from:

The AC Transfer busses.

The main busses.

The Battery bus.

The generator busses.

Correct! Wrong!

The purpose of the AC ground service bus is to power:

The cabin lighting

All statements are correct.

The battery charger

The utility outlets

Correct! Wrong!

The purpose of the cross tie relay is to:

Disconnect TR2 and TR3

Isolate transfer bus 1 and 2

Isolate DC bus 1 from DC bus 2

Disconnect TR1 and TR3

Correct! Wrong!

Illumination of the BAT DISCHARGE light indicates:

The battery bus is not powered.

Excessive battery discharge is detected with the battery switch ON.

The DC meter is in the BAT position with the battery switch ON.

The battery is being overcharged.

Correct! Wrong!

DC voltage and amperage may be read on the DC voltmeter and ammeter for the battery and each of the three TRs. The standby power and battery bus displays only DC voltage. Normal indication is:

24 +/- 10 volts.

12 +/- 4 volts.

14 +/- 4 volts.

26 +/- 4 volts.

Correct! Wrong!

During primary charge cycle operation battery voltage can be as high as 30 +/- 3 volts

The main and auxiliary batteries also provide backup power for the DC standby system only.

False.

True.

Correct! Wrong!

The main and auxiliary batteries also provide backup power for the AC and DC standby system.

The Engine Integrated Drive Generators (IDGs):

Operate whenever the engine is operating and cannot be completely isolated from their associated generator.

Allow the generator to maintain a constant speed throughout the normal range of operation

Are used in conjunction with a separate generator drive unit (CSD)

Adjust varying generator speeds to maintain a constant frequency throughout normal range of operation

Correct! Wrong!

Because engine generators power the transfer busses directly, and transfer busses are connected by a bus tie system, the loss of an engine driven generator will not necessarily result in the loss of any bus(ses).

False.

True.

Correct! Wrong!

With the STANDBY switch in the AUTO position, the loss of all engine or APU electrical power results in the automatic switching from the normal power source to the alternate source for standby power:

Will not occur.

On the ground only.

Inflight only.

Either inflight or on the ground.

Correct! Wrong!

On the ground, with the battery switch OFF and STANBY POWER Switch in AUTO, the Battery Bus is:

Not powered.

Correct! Wrong!

On the ground, with the BATTERY switch OFF and STANDBY POWER Switch in BAT, the switched hot battery bus is:

Not powered

Correct! Wrong!

Illumination of the GEN BUS OFF light indicates:

The generator is not supplying power to its associated generator bus.

The associated generator bus is not powered.

The IDG is not supplying power to its associated Transfer bus.

The associated transfer bus is not powered.

Correct! Wrong!

In flight, if the APU is supplying both AC Transfer busses, positioning the BUS TRANS switch to OFF will:

Cause both AC Transfer busses to lose power

Cause AC Transfer bus No.1 to lose power

Not cause either AC Transfer bus to fail.

Cause AC Transfer bus No.2 to lose power

Correct! Wrong!

The cross bus tie relay:

Must be manually opened using the BUS TRANSFER Switch during a Flight Director approach

Will trip off when AC volts reaches 26 volts (plus or minus 4 volts) as displayed on the AC voltmeter

Opens up if BUS TRANSFER switch is moved to OFF

Normally powers the Battery Charger and backs-up TR units 1 and 2 through a diode

Correct! Wrong!

A high oil temperature in the IDG would cause an automatic disconnect of the IDG.

True.

False.

Correct! Wrong!

Normal AC voltmeter indication for the APU generator with the AC busses loaded:

110 to 125 volts.

10 to 135 volts.

115 to 125 volts.

100 to 125 volts.

Correct! Wrong!

What is the source of power for TR2?

Transfer bus 2.

Transfer bus 2 or Transfer bus 1.

AC Standby bus

Transfer bus 1.

Correct! Wrong!

The TR3 cross bus tie relay automatically opens at glide slope capture to:

Ensure that the STANDBY DC is powered.

Provide more power to the AC STANDBY Bus.

Provide more power to DC bus 1.

Prevent a single bus failure from affecting both navigation receivers and Flight Control Computers (FCCs).

Correct! Wrong!

One basic principle of operation for the B737 electrical system is:

There is no paralleling of the AC power sources.

There is no paralleling of any power source.

All generator bus sources can be automatically connected by the Standby Power System.

An AC power source may be used in parallel with a DC power source.

Correct! Wrong!

For ground service, a ground service switch is available on:

Aft attendant´s panel

Forward attendant´s panel

The overhead panel in the flight deck.

Aft overhead panel on the Flight Deck

Correct! Wrong!

Illumination of the blue GEN OFF BUS light indicates:

The generator is not supplying power to its associated generator bus.

The IDG is not supplying power to its associated transfer bus

he associated transfer bus is not powered

The associated generator bus is not powered

Correct! Wrong!

AUTOMATIC LOAD SHEDDING (ENGINE GENERATORS) - For single generator operation, the system is designed to shed electrical load incrementally based on actual load sensing. When configuration changes to more source capacity (two generator operation), automatic load restoration of the main busses, galley busses and IFE buses occurs. Manual restoration of galley and main bus power can be attempted by:

Moving the CAB/UTIL Power Switch to OFF for 5 minutes minimum, then back ON.

Moving the CAB/UTIL Power Switch to OFF for 2 minutes minimum, then back ON.

Moving the CAB/UTIL Power Switch to OFF, then back ON.

Moving the CAB/UTIL Power Switch to OFF for 3 minutes minimum, then back ON.

Correct! Wrong!

What is the source of power for TR3?

AC standby bus.

Transfer bus 1.

Transfer bus 1 or 2.

Transfer bus 2.

Correct! Wrong!

When the aircraft batteries is the only source of power:

Both the Captain's and First Officer's PFD/ND displays remain operative but only DEU No 1 is powered until the battery is discharged

The Captain's inboard and outboard displays operate until the battery is discharged

The Captain's inboard and the First Officer's inboard and outboard displays are inoperative

The Captain's inboard and outboard displays operate until the battery is discharged and the First Officer's inboard and outboard displays operate for a minimum of 5 minutes

Correct! Wrong!

The ELEC light will illuminate in flight if:

A fault exists in the DC or Standby system.

A fault exists in the AC or Standby power system.

A fault exists in the AC, DC or the Standby system.

The ELEC light only operates on the ground.

Correct! Wrong!

Illumination of the STANDBY POWER OFF light indicates:

AC standby bus unpowered

Hot battery bus unpowered

DC bus 2 unpowered

DC bus 1 unpowered

Correct! Wrong!

Which is the power source for the AC standby bus?

Transfer bus 1 under normal conditions

Transfer bus 2

Battery Bus through the Static Inverter under normal conditions

AC main bus 1

Correct! Wrong!

It is possible to power one transfer bus with external power and the other transfer bus with the APU?

No.

Yes.

Correct! Wrong!

The TR UNIT will illuminate in flight if:

TR1 fails or TR2 and TR3 fail.

Any TR unit fails.

TR3 fails.

TR2 fails.

Correct! Wrong!

DC voltage and amperage may be read on the DC voltmeter and ammeter for the battery and each of the 3 TRs. The Standby power and battery bus displays only Dc voltage. Normal indication is ______ volts

26 +/- 6

26 +/-4

24 +/- 4

24 +/-2

Correct! Wrong!

The IDGs contain the generator and drive in a common housing, and are lubricated and cooled by a external oil system attached to the gearbox.

False.

True.

Correct! Wrong!

The IDGs contain the generator and drive in a common housing, and are lubricated and cooled by a self–contained oil system.

The switched hot battery bus is powered whenever:

Transfer bus 1 is powered.

AC ground service bus is powered.

TR1 is powered.

The battery switch is ON.

Correct! Wrong!

The auxiliary battery operates in parallel with the main battery when the battery is powering the standby bus.

False.

True.

Correct! Wrong!

Which bus supplies electrical power to the auxiliary battery charger?

AC ground service bus 1

Transfer bus 1

AC ground service bus 2

Transfer bus 2

Correct! Wrong!

During cruise, one engine driven generator drops off-line. Indications that the crew should see include:

Illumination of the fuel pump, probe heat, respective hydraulic pumps powered by the associated Transfer bus

All statements are correct.

A SOURCE OFF light and a GEN OFF BUS light

A TRANSFER BUS OFF light and a GEN OFF BUS light

Correct! Wrong!

Both On the ground and in flight a amber ELEC light comes on to indicate that a fault exists in DC power system or standby power system.

False.

True.

Correct! Wrong!

The ELEC light is inhibited in flight.

Both AC Transfer busses can be powered simultaneously by:

A single IDG on the ground or inflight and the APU generator while on the ground or inflight

No single source can power both AC Transfer busses simultaneously

The APU generator while on the ground or inflight

A single IDG on the ground or inflight

Correct! Wrong!

AUTOMATIC LOAD SHEDDING (ENGINE GENERATORS) - For single generator operation, the system is designed to shed electrical load incrementally based on actual load sensing. What is the first bus that is shed?

The galleys and main bus on transfer bus 2 are shed first

The DC standby bus is shed first.

The AC standby bus is shed first.

The galleys and main bus on transfer bus 1 are shed first

Correct! Wrong!

After the loss of all generators, two fully charged batteries have sufficient capacity to provide standby power for a minimum of:Two fully charged batteries have sufficient capacity to provide standby power for a minimum of

60 minutes

45 minutes

30 minutes

20 minutes

Correct! Wrong!

When the STANDBY POWER Switch is OFF:

The STANDBY PWR OFF light will be extinguished

The Static Inverter provides 28V DC power to Transfer Bus No.1.

The STANDBY PWR OFF light will be illuminated

Automatic switching is provided from normal power sources to alternate power sources

Correct! Wrong!

If the AC source powering a transfer bus fails, the transfer bus will remain unpowered.

True

False.

Correct! Wrong!

The TR3 Disconnect Relay:

Automatically opens at glide slope capture during a Flight Director or Autopilot ILS approach

Will trip off when AC volts reaches 26 volts (+ or - 4 Volts) as dispalyed on the AC Voltmeter.

Must be manually opened using the BUS TRANSFER Switch during a Flight Director approach

Normally powers the Battery Charger and backs-up TR units 1 & 2 through a diode

Correct! Wrong!

Transformer rectifier (TR) units and the main battery/battery charger supply DC power.

False.

True.

Correct! Wrong!

With external DC power connected to the external DC power receptacle:

The battery is paralleled with the DC External power source.

The APU can be started using DC external power.

All circuits normally powered by the battery are powered.

There is no external DC power receptacle.

Correct! Wrong!

The illumination of the GND POWER AVAILABLE light indicates:

Ground power is connected and meets airplane power quality standards.

Ground power is connected however no airplane power quality is measured.

The external power bus is powered by a ground power supply.

The Ground Service Bus is powered by a ground power supply.

Correct! Wrong!

The 115V AC Standby Bus is powered by:

The Battery Bus through the Static Inverter under normal conditions.

The Battery through the Static Inverter with a failure of both engine driven generators.

The 115V Transfer Bus No.1 under normal conditions and the Battery through the Static Inverter with a failure of both engine driven generators.

The 115V Transfer Bus No.1 under normal conditions.

Correct! Wrong!

The GROUND POWER AVAILABLE light will extinguish when:

The pneumatic ground cart is disconnected

The GROUND POWER switch is positioned ON

The AC ground power cart has been disconnected

The GROUND SERVICE switch is positioned ON

Correct! Wrong!

In flight if APU is the only source of electrical power:

No galley busses are automatically shed

Only galley bus C & D are automatically shed

Only galley bus A & B are automatically shed

All galley busses are automatically shed

Correct! Wrong!

What is the significance of an illuminated ELEC light?

The battery is discharged.

Two or more TRs have failed.

One of the three TRs has failed.

The DC system or standby system equipment has failed.

Correct! Wrong!

What is the purpose of the GROUND SERVICE switch?

Provide automatic control of ground service busses.

Provides automatic control of ground service bus.

Provide manual control of ground service busses.

Provide manual control of ground service bus.

Correct! Wrong!

Enables servicing airplane using external power without activating AC transfer busses.

The main battery charger is powered through:

AC main bus 1

Transfer Bus 1

DC bus 1

AC ground service bus 2

Correct! Wrong!

DC busses powered from the battery following a loss of both generators are:

Battery bus, DC Standby bus, Hot battery bus.

Battery bus, DC Standby bus, Hot battery bus & Switched hot battery bus.

Battery bus, DC Standby bus, Hot battery bus & Switched hot battery bus (even when the battery switch is OFF).

DC standby Bus, Hot Battery Bus & Switched hot battery bus.

Correct! Wrong!

Boeing 737NG - Electrical

Boeing 737NG – Electrical

Either generator or the APU can power both transfer buses. In the event a power source fails, what is required for that transfer bus to be powered by the opposite transfer bus power source?

Each IDG supplies its own bus system in normal operation and can also supply essential and non-essential loads of the opposite side bus system when one IDG is inoperative.

Galley busses are powered from:

The purpose of the AC ground service bus is to power:

The purpose of the cross tie relay is to:

Illumination of the BAT DISCHARGE light indicates:

DC voltage and amperage may be read on the DC voltmeter and ammeter for the battery and each of the three TRs. The standby power and battery bus displays only DC voltage. Normal indication is:

The main and auxiliary batteries also provide backup power for the DC standby system only.

The Engine Integrated Drive Generators (IDGs):

Because engine generators power the transfer busses directly, and transfer busses are connected by a bus tie system, the loss of an engine driven generator will not necessarily result in the loss of any bus(ses).

With the STANDBY switch in the AUTO position, the loss of all engine or APU electrical power results in the automatic switching from the normal power source to the alternate source for standby power:

On the ground, with the battery switch OFF and STANBY POWER Switch in AUTO, the Battery Bus is:

On the ground, with the BATTERY switch OFF and STANDBY POWER Switch in BAT, the switched hot battery bus is:

Illumination of the GEN BUS OFF light indicates:

In flight, if the APU is supplying both AC Transfer busses, positioning the BUS TRANS switch to OFF will:

The cross bus tie relay:

A high oil temperature in the IDG would cause an automatic disconnect of the IDG.

Normal AC voltmeter indication for the APU generator with the AC busses loaded:

What is the source of power for TR2?

The TR3 cross bus tie relay automatically opens at glide slope capture to:

One basic principle of operation for the B737 electrical system is:

For ground service, a ground service switch is available on:

Illumination of the blue GEN OFF BUS light indicates:

What is the source of power for TR3?

When the aircraft batteries is the only source of power:

The ELEC light will illuminate in flight if:

Illumination of the STANDBY POWER OFF light indicates:

Which is the power source for the AC standby bus?

It is possible to power one transfer bus with external power and the other transfer bus with the APU?

The TR UNIT will illuminate in flight if:

DC voltage and amperage may be read on the DC voltmeter and ammeter for the battery and each of the 3 TRs. The Standby power and battery bus displays only Dc voltage. Normal indication is ______ volts

The IDGs contain the generator and drive in a common housing, and are lubricated and cooled by a external oil system attached to the gearbox.

The switched hot battery bus is powered whenever:

The auxiliary battery operates in parallel with the main battery when the battery is powering the standby bus.

Which bus supplies electrical power to the auxiliary battery charger?

During cruise, one engine driven generator drops off-line. Indications that the crew should see include:

Both On the ground and in flight a amber ELEC light comes on to indicate that a fault exists in DC power system or standby power system.

Both AC Transfer busses can be powered simultaneously by:

AUTOMATIC LOAD SHEDDING (ENGINE GENERATORS) - For single generator operation, the system is designed to shed electrical load incrementally based on actual load sensing. What is the first bus that is shed?

After the loss of all generators, two fully charged batteries have sufficient capacity to provide standby power for a minimum of:Two fully charged batteries have sufficient capacity to provide standby power for a minimum of

When the STANDBY POWER Switch is OFF:

If the AC source powering a transfer bus fails, the transfer bus will remain unpowered.

The TR3 Disconnect Relay:

Transformer rectifier (TR) units and the main battery/battery charger supply DC power.

With external DC power connected to the external DC power receptacle:

The illumination of the GND POWER AVAILABLE light indicates:

The 115V AC Standby Bus is powered by:

The GROUND POWER AVAILABLE light will extinguish when:

In flight if APU is the only source of electrical power:

What is the significance of an illuminated ELEC light?

What is the purpose of the GROUND SERVICE switch?

The main battery charger is powered through:

DC busses powered from the battery following a loss of both generators are: