DC ELECTRIC - Dgca question bank for pilots

Results

#1. What are the advantages of an earth return system? 1.It is not a single wire system. 2.Short circuits are less likely. 3.Open circuits are less likely. 4.Reduced weight. 5.Easier fault detection and diagnosis.

1,2,3,4.

2,3,5.

3,4.

All of the above.

#2. How is the voltage regulator in a DC generator connected?

In series with field windings.

In series with the armature.

In Parallel with the field windings.

In parallel with the armature.

#3. Ohm’s law states that current is?

Directly proportional to voltage.

Directly proportional to resistance.

Directly proportional to the square of resistance.

Directly proportional to the square of voltage.

#4. Ohm’s law states that current is?

Inversely proportional to voltage.

Inversely proportional to resistance.

Directly proportional to the square of resistance.

Directly proportional to the square of voltage.

#5. If two batteries 12V, 40 Ampere hour batteries are connected in series they will provide?

12V 80 amps.

12V 40 amps.

24V 40 amps.

24V 80 amps.

#6. The voltage of a fully charged lead acid cell is normally?

1.7 V.

1.8 V.

1.9 V.

2.0 V.

#7. Connecting batteries in parallel to a resistive circuit will?

Increase both voltage and current.

Increase voltage but not affect current.

Increase current but not affect voltage.

Not affect voltage or current but increase battery life.

#8. Connecting two batteries in series to a resistive clrcuit will?

Increase both voltage and current.

Increase voltage but not affect current.

Increase current but not affect voltage.

Not affect voltage or current but increase battery life.

#9. If a current is passed through a conductor that is within a magnetic field?

A force will be exerted on the conductor.

The magnetic field will be intensified.

A force will be exerted on the conductor only if it is moved.

The magnetic field will increase the current.

#10. What is a ratiometer?

A moving coil instrument that is insensitive to changes in supply voltage.

A moving coil instrument that is sensitive to changes in supply voltage.

An instrument that indicates the ratio of currents from each generator in a coupled system.

An instrument that indicates the ratio of voltages from each generator in a coupled system.

#11. The loads on an aircraft busbar are connected?

In parallel so that voltage is proportional to the loads swiched on.

In series so that voltage is proportional to the loads swiched on.

In parallel so that current is proportional to the loads swiched on.

In series so that current is proportional to the loads swiched on.

#12. Resistance of 2 parallel loads can be calculated using?

1/RT=1/R1+1/R2.

Rr=R1+R2.

1/RT=R1+R2.

RT=1/R1+1/R2.

#13. When a battery nearly discharged?

The electrolyte begins to boil.

All of the distilled water evaporates from the electrolyte.

The voltage decreases.

The voltage and current decrease.

#14. A hot busbar?

Is one that is overloaded.

Is connected directly to the battery.

Is used to store energy when the generators are running.

Is used only in emergencies.

#15. A GCB?

Connects the generator to its busbar.

Connects the generators together.

Connects the individual generator busbars together.

Connects the generators to earth.

#16. What will happen if one generator is persistently over excited?

The GCB and SSB will trip.

The GCB and BCB will trip.

The GCB and over-exciter relay will trip.

The BCB and over-exciter relay will trip.

#17. Real load is equal to?

Torque on the CSDU.

CSDU torque x RPM.

CSDU RPM.

CSDU torque / RPM.

#18. A battery is tested using a voltmeter?

In series and with the loads switched on.

In series and with the loads switched off.

In parallel and with the loads switched on.

In parallel and with the loads switched off.

#19. OHM’s law is?

I=VR..

V=1/R.

I=V/R.

R=VI.

#20. Power in a Dc circuit is?

P=1/R.

P=1²R.

P=1²/R.

P=V/I.

#21. Connecting two identical batteries instead of one, in series with a resistive circuit will?

Double voltage and current.

Double voltage but not affect the current.

Double current only.

Double battery life.

#22. Electrical bonding? 1. Prevent static radio interference. 2.Prevent lighting strikes. 3. Helps in dissipating strikes. 4.Maintains zero PD between different parts of the airframe. 5.Maintains a constant PD between different parts of the airframe.

1,2,3,4.

2,3,4,5.

3,4.

All of the above.

#23. Power dissipated in a DC circuit is? 1.Zero. 2.IV 3.I²R. 4.I²/R 5.V²/R.

1,3,4,5.

2,3,5.

2,3,4,5.

All of the above.

#24. Connecting two identical batteries instead of one, in parallel in a resistive circuit will?

Double voltage and current.

Double voltage but not affect the current.

Double current but half the voltage.

Double battery life.

#25. If two 40 ampere hour batteries are connected in parallel they will provide?

80 amps for 1 hour.

80 amps for 2 hour.

40 amps for 1 hour.

40 amps for 3 hour.

render function for question type not found

#28. What power will be dissipated in the circuit below is?

17.72W.

3.204W.

9.288W.

24.96W.

render function for question type not found

#30. The total current through the battery in the circuit below is?

0.473A.

0.340A.

0.267A.

0.86A.

#31. How should a battery be checked for its state of charge?

On load using a voltmeter.

Off load using a voltmeter.

On load using an anmeter.

Off load using an ammeter

#32. How is initial excitation of a DC generator normally achieved?

Current from the battery.

Current from the hot bus bar.

Residual magnetism in the field windings

Field circuit current supplied.

#33. How are aircraft batteries normally connected?

In parallel to maximise voltage

In series to maximise ampere/hour rating.

In series to simplify circuit wiring.

In parallel to maximise amper/hour rating.

#34. Which of the following can be provided by a 100amp/hour battery?

2 volts for 50 hours.

50 amps for 2 hours

10 volts for 10 hours

20 ampls for 50 hours

#35. A non trip-free circuit breaker?

May be reset by pulling out the button

May be reset as many times as necessary to complete a flight.

Cannot be reset except on the ground

Can be held closed even when the circuit is faulty but might overload the circuit.

#36. Total resistance in a DC circuit is equal to?

1/R1+1/R2+1/Rs.

R1+R2+R3.

(R1+R2)/R2×R2).

(R1×R2)/(R1+R1).

#37. A reverse current relay is used to?

Trip the generator circuit breaker whenever generator output voltage exceeds 24 volts.

Trip whenever battery voltage exceeds generator output voltage

Prevent DC generators from being paralleled.

Enable the vital services bus bar to be powered by AC or DC when required.

#38. Electrical power in a DC circuit is?

I / E.

V² / R.

R /I.

V x R.

#39. As load increase on a shunt wound generator?

Voltage increases.

Voltage reduces

Current remains constant

Voltage remains constant

#40. If a system becomes open circuit?

The battery will become reverse connected

The circuit will become bridged.

Current will increase rapidly

Current will cease to flow

#41. The direction of rotation of a motor can be determined by applying?

Fleming's left hand rule

Fleming's right hand rule

The screw rule

Faraday's third law

#42. The direction of rotation of a generator can be determined by applying?

Fleming's left hand rule.

Fleming's right hand rule

The screw rule

Faraday's third law

#43. If a current is passed through a conductor in a magnetic field?

The magnetic field will intensify

The magnetic field will be negated

A force will act on the conductor

No force will act until the conductor is moved

#44. A battery is nearly discharged when?

The current increase with decreasing load

The current decreases with increasing load

The voltage increases with increasing load

The voltage decreases with increasing load

#45. If one cell of a 12 volt battery is dead?

The voltage will be 1/12th of its normal value.

The voltage will be 11/12th its normal value.

The battery is unserviceable and must be replaced immediately.

The capacity and voltage will be 11/12 th of their normal value.

#46. What is the difference between (1) a fuse and (2) a circuit breaker.

(1) operates on current while (2) operates on power

(1) can be reset while (2) cannot.

(1) operates on power while (2) operates on current

(1) cannot be reset but (2) can be

#47. What type of motor would be used to start a piston engine?

Series wound

Shunt would

Compound would

Synchronous

#48. What type of motor would be used to drive an inverter?

Series wound

Shunt wound

Compound wound

Synchronous

Synchronous Motors. These are basically alternators operated as motors. Alternating
current is applied to the stator but the rotor has a Direct Current power source.

#49. What type of motor would be used to drive a hydraulic pump?

Series wound

Shunt wound

Compound wound

Synchronous

#50. A relay is?

An electromagnetic switch in which the core moves.

An electromagnetic switch in which the core not move.

A rotary indicator employing electromagnetic fields and return springs.

A remote amplification device

The solenoid has a moving core whereas the relay has a stationary core and an attracted
armature.

#51. Fuses are rated in terms of?

The amount of power they can carry

The amount of voltage they can carry

The amount of current they can carry

Their rupture time.

#52. Fuses will blow when?

The circuit has become open circuit.

Too many loads have been switched off, so excessive current flows in the remaining loads.

The loads have become connected in series

The circuit has become short circuited

#53. If battery charge rate is very high after starting the engine with a Nicad battery?

Shut down immediately because the battery is in thermal runaway.

This is normal provided charge rate remains constant

This is normal provided charge rate falls to a lower figure after a brief period.

This indicates that generator voltage regulator is defective, so the engine should be shut down immediately

#54. The voltage of a Nicad battery begins to fall following a total generator failure?

This is normal and should be ignored

This indicates that the battery is about to fail

This indicates that too many loads have been shed

This indicates that the battery is in thermal runaway

#55. Static wicks?

Are not used in DC aircraft

Are part of the earth return circuit

Discharge static charges in flight

Discharge static charges at all times.

#56. Metal sheaths around cables?

Protects sensitive circuits from lightning strikes.

Reduces radio interference

Improves or replaces bonding.

Prevents chafing

#57. Capacitors in high energy ignition systems?

Protect the contact breaker points from arcing.

Store energy

Control discharge rate.

Product the inductive coils from excessive currents.

#58. A differential cut out in a DC distribution system?

Maintains the required voltage differential between the generators and battery

Maintains both generators at the same output voltage after parellelling

Ensures that the output voltages of the two generators are approximately equal before paralleling

Connects the two generator bus bars in parallel

#59. A bus tie breaker (BTB) in a split bus system?

Connects the bus bars of each generator together in parallel

Connects the bus bars of the two generators in serise

Ensures that the generators can be parallelled only when one has failed

Ensures that the generators can be parallelled only when both are serviceable.

#60. If two generators are connected in parallel when not at the same output voltage?

Residual currents will flow into the battery causing it to overheat.

Circulating currents will flow between the generators to equalise the voltages.

Polarising currents will flow between the two generators causing the fuses to blow.

Circulating currents will flow between the two generators causing one to drive the other.

#61. The current within the armature of a DC generator is?

Equal to the value of the output current

Very low

#62. The current in the armature of a DC motor must be?

Equal to the rms value of the output current

DC.

AC.

Very low

#63. Loads driven by a battery must be?

In series so that all share the same voltage

In series so that all carry the same current

In parallel so that carry the same current

In parallel so that all carry the same voltage.

#64. A differential cut out must detect pd between?

The hot but bar and the battery.

The individual generators

The generator and its loads

The generator but bar and battery bus bar.

#65. A centre zero ammeter is normally fitted __ in order to measure ?

Downstream of the battery bus bar measure discharge rate.

Upstream of the generator bus bar measure discharge rate

Downstream f the generator measure charge rate.

Between the battery and its bus bar measure charge/discharge rate.

#66. A left zero ammeter is normally fitted _ in order to measure _____?

Between generator and battery bus bar measure charge rate

Upstream of the generator bus bar measure discharge rate

Downstream of the battery measure charge rate.

Between the battery and its bus bar measure charge/discharge rate.

#67. If the RPM of a generator decrease, the resistance of its carbon pile will?

Increase

Decrease

Remain constant

Increase then decrease at very high RPM

#68. If the load on a generator increases, the resistance of its carbon pile will?

Increase

Decrease

Remain constant

Increase then decrease at very high RPM.

#69. A reverse current cut out?

Is used to parallel generators

Prevents one generator form driving the other in a parallel system

Opens if the generator voltages becomes excessive

Closes when generator voltages is greater than battery voltage.

#70. An under-volting generator will be indicated by?

The load ammeter and warning light

The warning light

The load ammeter

The generator voltmeter

#71. If 10 fully charged lead acid cells are connected in parallel the open circuit voltage will be approximately?

2.2 Volts

2.4 Volts

22 Volts

24 Volts

#72. If 10 fully charged lead acid cells are connected in series the open circuit voltage will be approximately?

2.2 Volts

2.4 Volts

22 Volts

24 Volts

#73. The charge state of a ____ battery can be checked by testing voltage on and off line, but this method cannot be used for a _ battery?

Lead acid alkaline

Alkaline Lead acid

Secondary primary

Primary secondary.

#74. Induced voltage in the armature of a DC generator is?

Constant at any given RPM.

Greatest when the axis of the coil is at right angles to the field

Greatest when the axis of the coil is parallel to the field

Independent of coil alignment

#75. The conductor in motor will?

Turn clockwise

Turn anti- clockwise.

Stop.

Turn clock wise or anti- clock wise depending on voltage.

#76. The conductor in this generator is?

Turning clockwise

Turning anti-clock wise.

Stopped

Turning clock wise or anti- clock wise depending on voltage.

#77. A capacitor in series with a load in a DC circuit will?

Block current flow to load.

Increase current few to the load

Allow only AC to flow through the load

Prevent radio interference

#78. Current in the armature of a DC generator is _ and is by the ___?

Very small amplified commutator

DC inverted slip rings.

AC rectified commutator.

AC rectified diode pack

#79. If the number of parallel loads connected to a DC generator are increased the generator will?

Become easier to turn because electrical resistance will decrease.

Harder to turn because electrical resistance will increase

Become harder to turn because more power will be drawn from it.

The required turning force will remain constant

#80. An illuminated DC generator warning light indicates that ?

The battery voltage is less than 24V and the reverse current cut out is open

The battery voltage is greater than generator voltage and the reverse current cut out is open.

The battery voltage is greater than the generator voltage and the reverse current cut out is closed

The generator has failed and must be switched off immediately

#81. The most reliable indication of battery discharge rate following a total generator failure is?

A voltmeter

An ammeter

A wattmeter

A ratiometer.

#82. Following a total generator failure the _______ of an alkaline battery will _ whereas that of a lead acid battery will __?

Voltage decrease gradually remain constant then fall suddenly

Voltage remain constant then fall suddenly decrease gradually

Current increase gradually remain constant then fall suddenly

Current remain constant then fall suddenly increase gradually

#83. Loads are connected to a bus bar

In series ensure all receive the same current

In series to reduce overall current flow

In parallel to reduce overall resistance

In parallel to ensure all receive the same voltage.

#84. As the number of loads on a bus bar increases, the total resistance and the generator

Increases becomes harder to turn

Decreases becomes harder to turn

Increases becomes easier to turn

Decreases becomes easier to turn

#85. The voltage regulator is a _ in ___ with the field to maintain constant output voltage?

Constant resistance parallel.

Constant resistance series .

Variable resistance parallel

Variable resistance series

#86. The electro-magnetic brake coil of an actuator is energised?

By the back emf whenever the actuator is stopped

By back emf whenever the actuator is running

By supply current whenever the actuator is stopped

By supply current whenever the actuator is running

#87. Actuator limit switches?

Are open whenever the actuator is running

Are open whenever the actuator is stopped

Close when the actuator reaches its limits of travel

Open when the actuator reaches its limits of travel

#88. In a carbon pile voltage regulator, the spring is biased towards ________ and the _ is biased towards _____?

High resistance current coil low resistance

High resistance volts oil low resistance

Low resistance current coil high resistance

Low resistance volts coil high resistance

#89. Electrical fuses are connected in _ to ?

Parallel reduce resistance.

Parallel increase resistance

Series sense total voltage

Series sense total current

#90. The cores of elector-magnetic coils are laminated to?

Control the direction of the field

Reduce manufacturing costs

Reduce electrical resistance

Increase efficiency.

#91. As the throttle is moved from idle to take-off power?

The voltage regulator is unaffected

The resistance of the voltage regulator decreases

The resistance of the voltage regulator increases

Generator output voltage increases

#92. If two generators are paralleled when at different voltages?

One will burn out.

Large circulating currents will flow

Large eddy currents will flow

The loads will receive different voltages

#93. The limit switches of a linear actuator in mid travel are?

Both open

Both closed

One open and one closed

It depends on the direction of travel

#94. If a generator ammeter is indicating 14 Amps?

The battery is dead

The battery is charging

The generator is off line

The generator is on line

#95. If a centre zero ammeter is indicating minus 12 amps?

The battery is charging

The battery is discharging

The generator is on line

The voltage regulator is defective

#96. Thermal runaway is most likely to occur when?

A lead acid battery is charging very quickly

A lead acid battery is discharging very quickly

An alkaline battery is charged very quickly

An alkaline battery is discharging very quickly.

#97. EMF is measured in?

Amps

Farads

Coulombes

Volts

#98. A capacitor connected in series will?

Make current lag voltage in a DC circuit

Pass only DC current

Block DC current

Reduce impedance in a DC circuit.

#99. The total power drawn by the circuit illustrated below is?

5 KW.

50 KW.

280 W.

78.4 W.

#100. The total current drawn by the circuit illustrated below is?

2.8A.

28A.

280W.

1.12 A

Finish

Results

#1. What are the advantages of an earth return system? 1.It is not a single wire system. 2.Short circuits are less likely. 3.Open circuits are less likely. 4.Reduced weight. 5.Easier fault detection and diagnosis.

#2. How is the voltage regulator in a DC generator connected?

#3. Ohm’s law states that current is?

#4. Ohm’s law states that current is?

#5. If two batteries 12V, 40 Ampere hour batteries are connected in series they will provide?

#6. The voltage of a fully charged lead acid cell is normally?

#7. Connecting batteries in parallel to a resistive circuit will?

#8. Connecting two batteries in series to a resistive clrcuit will?

#9. If a current is passed through a conductor that is within a magnetic field?

#10. What is a ratiometer?

#11. The loads on an aircraft busbar are connected?

#12. Resistance of 2 parallel loads can be calculated using?

#13. When a battery nearly discharged?

#14. A hot busbar?

#15. A GCB?

#16. What will happen if one generator is persistently over excited?

#17. Real load is equal to?

#18. A battery is tested using a voltmeter?

#19. OHM’s law is?

#20. Power in a Dc circuit is?

#21. Connecting two identical batteries instead of one, in series with a resistive circuit will?

#22. Electrical bonding? 1. Prevent static radio interference. 2.Prevent lighting strikes. 3. Helps in dissipating strikes. 4.Maintains zero PD between different parts of the airframe. 5.Maintains a constant PD between different parts of the airframe.

#23. Power dissipated in a DC circuit is? 1.Zero. 2.IV 3.I²R. 4.I²/R 5.V²/R.

#24. Connecting two identical batteries instead of one, in parallel in a resistive circuit will?

#25. If two 40 ampere hour batteries are connected in parallel they will provide?

#28. What power will be dissipated in the circuit below is?

#30. The total current through the battery in the circuit below is?

#31. How should a battery be checked for its state of charge?

#32. How is initial excitation of a DC generator normally achieved?

#33. How are aircraft batteries normally connected?

#34. Which of the following can be provided by a 100amp/hour battery?

#35. A non trip-free circuit breaker?

#36. Total resistance in a DC circuit is equal to?

#37. A reverse current relay is used to?

#38. Electrical power in a DC circuit is?

#39. As load increase on a shunt wound generator?

#40. If a system becomes open circuit?

#41. The direction of rotation of a motor can be determined by applying?

#42. The direction of rotation of a generator can be determined by applying?

#43. If a current is passed through a conductor in a magnetic field?

#44. A battery is nearly discharged when?

#45. If one cell of a 12 volt battery is dead?

#46. What is the difference between (1) a fuse and (2) a circuit breaker.

#47. What type of motor would be used to start a piston engine?

#48. What type of motor would be used to drive an inverter?

#49. What type of motor would be used to drive a hydraulic pump?

#50. A relay is?

#51. Fuses are rated in terms of?

#52. Fuses will blow when?

#53. If battery charge rate is very high after starting the engine with a Nicad battery?

#54. The voltage of a Nicad battery begins to fall following a total generator failure?

#55. Static wicks?

#56. Metal sheaths around cables?

#57. Capacitors in high energy ignition systems?

#58. A differential cut out in a DC distribution system?

#59. A bus tie breaker (BTB) in a split bus system?

#60. If two generators are connected in parallel when not at the same output voltage?

#61. The current within the armature of a DC generator is?

#62. The current in the armature of a DC motor must be?

#63. Loads driven by a battery must be?

#64. A differential cut out must detect pd between?

#65. A centre zero ammeter is normally fitted ____________ in order to measure __________?

#66. A left zero ammeter is normally fitted _______ in order to measure ___________?

#67. If the RPM of a generator decrease, the resistance of its carbon pile will?

#68. If the load on a generator increases, the resistance of its carbon pile will?

#69. A reverse current cut out?

#70. An under-volting generator will be indicated by?

#71. If 10 fully charged lead acid cells are connected in parallel the open circuit voltage will be approximately?

#72. If 10 fully charged lead acid cells are connected in series the open circuit voltage will be approximately?

#73. The charge state of a ____________ battery can be checked by testing voltage on and off line, but this method cannot be used for a _________ battery?

#74. Induced voltage in the armature of a DC generator is?

#75. The conductor in motor will?

#76. The conductor in this generator is?

#77. A capacitor in series with a load in a DC circuit will?

#78. Current in the armature of a DC generator is _______ and is ________ by the _________?

#79. If the number of parallel loads connected to a DC generator are increased the generator will?

#80. An illuminated DC generator warning light indicates that ?

#81. The most reliable indication of battery discharge rate following a total generator failure is?

#82. Following a total generator failure the _____________ of an alkaline battery will ___________ whereas that of a lead acid battery will ______?

#65. A centre zero ammeter is normally fitted __ in order to measure ?

#66. A left zero ammeter is normally fitted _ in order to measure _____?

#73. The charge state of a ____ battery can be checked by testing voltage on and off line, but this method cannot be used for a _ battery?

#78. Current in the armature of a DC generator is _ and is by the ___?

#82. Following a total generator failure the _______ of an alkaline battery will _ whereas that of a lead acid battery will __?

#84. As the number of loads on a bus bar increases, the total resistance and the generator

#85. The voltage regulator is a _ in ___ with the field to maintain constant output voltage?

#88. In a carbon pile voltage regulator, the spring is biased towards ________ and the _ is biased towards _____?

#89. Electrical fuses are connected in _ to ?