Boeing B737 MAX - Electrical

Illumination of the BAT DISCHARGE light indicates:

The battery bus is not powered.

The battery is being overcharged.

Excessive battery discharge is detected with the battery switch ON.

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

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 DC bus 1.

Provide more power to the AC STANDBY Bus.

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

Correct! Wrong!

The TR3 Disconnect Relay:

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

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

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

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

Correct! Wrong!

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

Not cause either AC Transfer bus to fail.

Cause both AC Transfer busses to lose power

Cause AC Transfer bus No.2 to lose power

Cause AC Transfer bus No.1 to lose power

Correct! Wrong!

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

The battery charger

All statements are correct.

The utility outlets

The cabin lighting

Correct! Wrong!

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 battery switch must be ON.

The generator switch must be OFF.

The battery switch must be OFF.

The BUS TRANS switch must be in the AUTO position.

Correct! Wrong!

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

True.

False.

Correct! Wrong!

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

Which bus supplies electrical power to the auxiliary battery charger?

Transfer bus 2

AC ground service bus 2

Transfer bus 1

AC ground service bus 1

Correct! Wrong!

When the aircraft batteries is the only source of power:

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

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

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

Correct! Wrong!

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

Not powered.

Correct! Wrong!

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

False.

True.

Correct! Wrong!

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

Battery bus, DC Standby bus, Hot battery bus.

DC standby Bus, Hot Battery Bus & Switched 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).

Correct! Wrong!

The cross bus tie relay:

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

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

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

Opens up if BUS TRANSFER switch is moved to OFF

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!

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

A single IDG on the ground or inflight

The APU generator while on the ground or inflight

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

24 +/-2

24 +/- 4

26 +/- 6

26 +/-4

Correct! Wrong!

Illumination of the GEN BUS OFF light indicates:

The associated transfer bus is not powered.

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

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

The associated generator bus is not powered.

Correct! Wrong!

What is the source of power for TR2?

Transfer bus 2.

AC Standby bus

Transfer bus 1.

Transfer bus 2 or Transfer bus 1.

Correct! Wrong!

The main battery charger is powered through:

Transfer Bus 1

AC main bus 1

DC bus 1

AC ground service bus 2

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, DC or the Standby system.

A fault exists in the AC or Standby power system.

The ELEC light only operates on the ground.

Correct! Wrong!

The GROUND POWER AVAILABLE light will extinguish when:

The GROUND POWER switch is positioned ON

The GROUND SERVICE switch is positioned ON

The pneumatic ground cart is disconnected

The AC ground power cart has been disconnected

Correct! Wrong!

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

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

There is no paralleling of the AC power sources.

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

There is no paralleling of any power source.

Correct! Wrong!

When the STANDBY POWER Switch is OFF:

The STANDBY PWR OFF light will be illuminated

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

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

The STANDBY PWR OFF light will be extinguished

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 forrna minimum of

30 minutes

45 minutes

60 minutes

20 minutes

Correct! Wrong!

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

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

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

Correct! Wrong!

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

All galley busses are automatically shed

No galley busses are automatically shed

Only galley bus A & B are automatically shed

Only galley bus C & D are automatically shed

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:

Either inflight or on the ground.

Will not occur.

On the ground only.

Inflight only.

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!

What is the source of power for TR3?

AC standby bus.

Transfer bus 2.

Transfer bus 1.

Transfer bus 1 or 2.

Correct! Wrong!

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

True.

False.

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:

14 +/- 4 volts.

26 +/- 4 volts.

24 +/- 10 volts.

12 +/- 4 volts.

Correct! Wrong!

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

What is the significance of an illuminated ELEC light?

The battery is discharged.

The DC system or standby system equipment has failed.

One of the three TRs has failed.

Two or more TRs have failed.

Correct! Wrong!

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

A TRANSFER BUS OFF light and a GEN OFF BUS light

A SOURCE OFF light and a GEN OFF BUS light

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

All statements are correct.

Correct! Wrong!

Galley busses are powered from:

The AC Transfer busses.

The Battery bus.

The generator busses.

The main busses.

Correct! Wrong!

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

True.

False.

Correct! Wrong!

Which is the power source for the AC standby bus?

Transfer bus 2

Transfer bus 1 under normal conditions

Battery Bus through the Static Inverter under normal conditions

AC main bus 1

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.

True.

False.

Correct! Wrong!

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

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

Yes.

No.

Correct! Wrong!

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

True

False.

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!

Illumination of the blue GEN OFF BUS light indicates:

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

he associated transfer bus is not powered

The associated generator bus is not powered

The IDG is not supplying power to its associated transfer bus

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.

True.

False.

Correct! Wrong!

The ELEC light is inhibited in flight.

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

100 to 125 volts.

110 to 125 volts.

115 to 125 volts.rn

10 to 135 volts.

Correct! Wrong!

The switched hot battery bus is powered whenever:

The battery switch is ON.

TR1 is powered.

Transfer bus 1 is powered.

AC ground service bus is powered.

Correct! Wrong!

The 115V AC Standby Bus is powered by:

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

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

The Battery Bus through the Static Inverter under normal conditions.

Correct! Wrong!

The TR UNIT will illuminate in flight if:

TR1 fails or TR2 and TR3 fail.

TR3 fails.

Any TR unit fails.

TR2 fails.

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.

True.

False.

Correct! Wrong!

What is the purpose of the GROUND SERVICE switch?

Provide manual control of ground service busses.

Provide manual control of ground service bus.

Provide automatic control of ground service busses.

Provides automatic control of ground service bus.

Correct! Wrong!

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

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

There is no external DC power receptacle.rn

The APU can be started using DC external power.

The battery is paralleled with the DC External power source.

All circuits normally powered by the battery are powered.

Correct! Wrong!

Illumination of the STANDBY POWER OFF light indicates:

DC bus 1 unpowered

DC bus 2 unpowered

AC standby bus unpowered

Hot battery bus unpowered

Correct! Wrong!

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

Aft overhead panel on the Flight Deck

Aft attendantu00b4s panel

The overhead panel in the flight deck.

Forward attendantu00b4s panel

Correct! Wrong!

The purpose of the cross tie relay is to:

Isolate transfer bus 1 and 2

Disconnect TR2 and TR3

Disconnect TR1 and TR3

Isolate DC bus 1 from DC bus 2

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 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.

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

Correct! Wrong!

The illumination of the GND POWER AVAILABLE light indicates:

Ground power is connected and meets airplane power quality standards.

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

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

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

Correct! Wrong!

Boeing 737 MAX - Electrical

Quiz

Boeing B737 MAX - Electrical

Illumination of the BAT DISCHARGE light indicates:

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

The TR3 Disconnect Relay:

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

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

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

Which bus supplies electrical power to the auxiliary battery charger?

When the aircraft batteries is the only source of power:

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

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

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

The cross bus tie relay:

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

Both AC Transfer busses can be powered simultaneously by:

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

Illumination of the GEN BUS OFF light indicates:

What is the source of power for TR2?

The main battery charger is powered through:

The ELEC light will illuminate in flight if:

The GROUND POWER AVAILABLE light will extinguish when:

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

When the STANDBY POWER Switch is OFF:

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 forrna minimum of

The Engine Integrated Drive Generators (IDGs):

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

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:

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).

What is the source of power for TR3?

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

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:

What is the significance of an illuminated ELEC light?

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

Galley busses are powered from:

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

Which is the power source for the AC standby bus?

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.

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

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

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?

Illumination of the blue GEN OFF BUS light indicates:

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.

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

The switched hot battery bus is powered whenever:

The 115V AC Standby Bus is powered by:

The TR UNIT will illuminate in flight if:

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.

What is the purpose of the GROUND SERVICE switch?

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

Illumination of the STANDBY POWER OFF light indicates:

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

The purpose of the cross tie relay is to:

The illumination of the GND POWER AVAILABLE light indicates: