Electrical

Question 1

What power sources can cross tie on the ground?

Answer 1

The engine generators.

Question 2

What is the electrical source priority?

Answer 2

On side engine generator
APU generator
External power unit
Off side generator cross tie

Question 3

What does the reset position of the generator control switch do?

Answer 3

Closes the generator control relay.

Question 4

When only the battery switch is on what buses are powered?

Answer 4

DC Transfer Bus
Battery Direct Bus
Battery Bus

Question 5

What are the two purposes of the ground service bus?

Answer 5

To provide power to those circuits necessary for ground service, and to provide an alternate means of battery charging. (B2 8-120)

Question 6

Is there a way to monitor external power?

Answer 6

No AC load meter exists for external power.

Question 7

At what RPM should you disconnect a CSD?

Answer 7

A higher speed to allow for a smoother disconnect.

Question 8

Can a CSD be reconnected?

Answer 8

Yes, but only on the ground by a mechanic.

Question 9

What is the electrical power source for the pneumatic pressure gauge?

Answer 9

Emergency AC bus

Question 10

What is the electrical power source for the augmentation valve?

Answer 10

Respective DC bus

Question 11

What is the power source for the start valve solenoid?

Answer 11

The DC Transfer bus

Question 12

How do you verify an AC EMER BUS OFF light?

Answer 12

By looking for a “GYRO” flag in the captains ADI

Question 13

What normally powers the DC Transfer bus?

Answer 13

The Left AC Bus through the Left DC Bus

Question 14

How would you identify a differential fault in the “feeder” zone?

Answer 14

Move Generator switch to reset and off and observe no volts and frequencies.

Question 15

What is needed for battery charging to occur?

Answer 15

Ground Service AC bus powered, battery switch on, emergency switch off.

Question 16

How would you verify the DC TRANSFER BUS OFF light?

Answer 16

By doing a fire warning test.

Question 17

Is the DC cross tie automatic?

Answer 17

No

Question 18

How many circuit breakers must be pulled to disconnect a Transformer Rectifiers from its power source?

Answer 18

3, one for each phase of the AC input.

Question 19

What is the power source for the #2 Transformer Rectifier on the right side?

Answer 19

The Ground Service Bus

Question 20

What happens if you turn off the Battery Bus if you have the Emergency Power switch on?

Answer 20

You will lose the DC Transfer Bus and the Battery Bus, along with battery charging.

Question 21

List some items (3) powered by the Battery Direct Bus

Answer 21

Emergency Inverter
DC Emergency Bus
Fuel Fill and Transfer Valves

Question 22

How many batteries are on board?

Answer 22

Two 14 volt NICAD batteries.

Question 23

What are the Major Faults in the Electrical System? (2)

Answer 23

Generator Bus Differential Feeder Fault
Generator Bus Short

(B2 8-127)

Question 24

What are the Minor Faults in the Electrical System? (5)

Answer 24

Overvoltage
Undervoltage
Underfrequency
Overspeed
Incorrect phase sequence

(B2 8-127)

Question 25

What will cause the AC Crosstie to lock open?

Answer 25

A major fault

Question 26

After a Major Fault how would you know that it is a Generator Differential Feeder Fault? Can the associated bus be powered and if so by what?

Answer 26

If zero voltage and zero frequency are observed on the associated voltmeter for that bus. Yes it can be powered by the APU.

Question 27

After a Major Fault how would you know that a Generator Bus Short has occurred? Can the associated bus be powered and if so by what?

Answer 27

If good voltage is observed on the voltmeter for the associated bus. No it must not be powered by the APU as a short exists on the bus.

Question 28

During a Minor Fault will the AC Crosstie automatically close?

Answer 28

Yes

Question 29

What does the Ground Service AC Bus receive power from?

Answer 29

Right Generator Bus APU External Power

Question 30

Generally what kind of items do the Generator Buses supply power to? Where do these buses get their power from?

Answer 30

High current draw items. They receive their power directly from the generator.

Question 31

Generally what kind of items do the L/R AC Buses supply power to? Where do these buses get their power?

Answer 31

Low current draw items and the DC power distribution system. They receive power directly from the onside Generator Bus.

Question 32

What is the purpose of a Generator Relay?

Answer 32

To provide a means of disconnecting the generator's output from the Generator Bus. (B2 8-124)

Question 33

What is the purpose of the Generator Control Relay?

Answer 33

Often referred to as the Field Relay this provides a means of controlling the generator field, or the way for the generator to produce current.

Question 34

If the Generator Control Relay opens what other relay opens?

Answer 34

The Generator Relay will also open. The reason both switches exist is because you need a way to disconnect the power to the system (Generator Relay) and you need a way to stop the generator from producing power (Generator Control Relay).

Question 35

What normally powers the Emergency DC Bus?

Answer 35

The Left DC Bus which is in turn powered by the Left AC Bus.

Question 36

What gauges will work on Emergency Power?

Answer 36

``` Airspeed Cpt ADI without the FD Cpt Altimeter Cpt VSI EGT N1 N2 Oil pressure low lights ```

Question 37

Can one TR power the entire airplane?

Answer 37

Yes

Question 38

What indicates that the Emergency DC Bus is unpowered?

Answer 38

Captains pitot heat is inoperative.

Question 39

What do the blue APU and External Power Available lights mean?

Answer 39

Power is available, meets frequency/voltage requirements, and the phase sequence is correct.

Question 40

All temperature readings are powered by what?

Answer 40

AC power

Question 41

All direct reading items are powered by what?

Answer 41

DC power

Question 42

All pressure reading items are powered by what?

Answer 42

AC power