3272-11 sys (1.14)

On a split bus electrical system, the bus tie breakers are. always closed in flight. always open in flight. only closed in an emergency.

Parallel electrical system bus tie breakers are. closed in flight and open on ground. closed on ground and open in flight. always closed in flight.

Whilst synchronising generators, frequency bias is adjusted on. the on-line generator. all generators. the on-coming generator.

The GCR will trip during over-voltage. based upon a fixed time delay circuit. based upon the amplitude of the over-voltage. immediately.

In a constant voltage AC generator, the voltage is regulated by. a 3-phase transformer. varying field voltage. varying field current.

A vibrator type voltage regulator regulates field current by. just a pair of contact breaker points. a resistor in parallel with a pair of contact breaker points. a resistor in series with a pair of contact breaker points.

When a current transformer is disconnected, what should be done?. Resistor placed across terminals. Left open circuit. Terminals shorted.

What does the differential sensing coil sense?. Volts. Power. Current.

Where does the GCU gets its power?. RAT. PMG. Battery.

Galley loads are wired in. either series or parallel depending on the design. series. parallel so load shedding will lower current consumption.

In a merz-price protection system of a single phase, if, when a fault occurs, only one relay contactor opens,. only the relay on the side which has the fault will energise. then it is probable that one of the relays has failed short circuit. then it is probable that one of the coils has failed open circuit.

A fuse-type current limiter. can be used as a radio suppressor. limits current flow to a load. opens a circuit after a time/current condition has been exceeded.

When a load is shed from a busbar, the. busbar voltage decreases. current consumption from the bar decreases. busbar voltage increases.

In unparalleled AC generation systems, the phase rotation of one generator in relation to the others. must be synchronised prior to paralleling. is unimportant. must be BCA.

In a multi-generator system, the generator which takes more than its reactive power share is protected by. over-current and under-current protection circuits. over-excitation and under-excitation protection circuits. over-voltage and under-voltage protection circuits.

In a pulsed width modulating type voltage regulator, the generator output voltage is increased by. increasing the voltage sensed by the voltage regulator. increasing the mark to space ratio. decreasing the mark to space ratio.

Sharing of electrical loads by paralleled DC generators is controlled by. automatic load shedding. equalising circuits which control the field excitation of the generators. equalising circuits which control the speed of the generators.

Excessive commutator sparking can be caused by. rotating field diode failure. weak spring tension. brushes positioned on MNA.

Before checking the SG of a battery recently removed from an aircraft. take the temperature of the electrolyte. carry out a capacity test. allow to stabilise for one hour.

On an AC external power plug, the interlock circuit is controlled by pins. E and F. A and B. C and D.

Over-voltage protection circuits are activated. after a fixed time delay. dependent on the magnitude of the overvoltage. before the over voltage limit is exceeded.

A diode connected across a coil will. prevent the coil being fitted the wrong way. prevent back EMF and allow faster switching. suppress arcing when relay is opening and closing.

Which fault does not always trip the GCR?. Over-frequency and under-frequency. Under-frequency and under-volts. Over-frequency and over-volts.

Differential protection in a generating system. detects current difference between source and load. uses the volts coil to trip the GCR. detects voltage difference between source and load.

Open phase sensing on a current transformer. is detected on generator neutral circuit. is detected using all phases. is detected using any phase.

If the battery is switched off in flight, the. battery is disconnected from bus. captain's instruments will be powered from the standby bus. generator voltage falls to zero.

To flash a generator field the. generator is on line and producing a voltage less than the flashing voltage. generator must be stationary. generator rotates but is not on line.

Voltage is controlled by. the voltage regulator. the constant speed drive. the swashplate.

Distilled water should be added to a ni-cad battery. only in the battery workshop. when fully charged. at any time.

Overflowing electrolyte in a ni-cad battery indicates. not enough charging current. low electrolyte temperature. excessive charging current.

During a normal engine shutdown, generator tripping is initiated by. underfrequency. undervoltage. overcurrent.

What would you use to neutralise nicad battery spillage?. Boric acid. Distilled water. Bicarbonate of soda.

Before operating generators in parallel, their voltages should be matched to prevent. overloading the generator drive and shearing of splines. voltage spikes of sufficient magnitude to trigger GCU overvoltage circuits. large circulating currents developing.

Consumer loads are connected to a busbar. in series so when loads are shed voltage is reduced. in series so when loads are shed current is reduced. in parallel so when loads are shed current is reduced.

A current transformer connected on the neutral star point of a generator is for. overload protection. differential current protection. negative sequence protection.

Differential protection as applied to AC generation systems compares. ambient pressure to cabin pressure. generator voltage to busbar voltage. generator current to busbar current.

In an AC generation system, the frequency and phase rotation. is of no consequence after paralleling. must be synchronised prior to paralleling. must be out of phase prior to paralleling.

Diodes are placed across a contactor to. prevent contact bounce. ensure smooth contactor operation. speed up operation by reducing back EMF.

Placing the battery master switch to off during flight will. shut down the APU. isolate the battery from the main busbar. disconnect all power to the main busbar.

Whilst operating paralleled AC constant frequency generators, it is important to maintain generator outputs at the same voltage. to prevent a circulating current of considerable magnitude developing between two or more generators. to prevent a circulating current developing between two or more TRUs. to prevent CSD shock loading.

A voltage regulator installed in series with a generator field. uses a current coil in parallel with generator output. uses a voltage coil in parallel with generator output. uses a voltage coil in series with generator output.

CSD warning lights on the flight deck normally indicate. low oil pressure, low oil temperature. high oil pressure, low oil temperature. low oil pressure, high oil temperature.

The output frequency of a hydraulically driven standby generator is controlled by. an IDG. a CSD. an hydraulically actuated swash plate.

An AC generator used with a CSD. does not need a voltage controller because current is kept constant. does not need a voltage controller because voltage is kept constant. needs a voltage controller to maintain voltage with increasing load.

Power to a GCU is supplied. initially by a 'field tickling' supply and then PMG output. by the battery bus or rectified generator output. by the generator output only.

Trip signals for a GCR are. underfrequency and overcurrent. overfrequency and undervoltage. differential protection and undervoltage.

Abnormal CSD operation is monitored on the flight deck by observing indications of. high oil temperature / low oil pressure. low oil quantity / low oil temperature. High oil temperature / low oil quantity.

Wires in hot temperature areas should be bound with. PVC. Teflon. Nomex.

A heat gun should be operated at. 100°C below the specified. the specified temperature. 100°C above the specified.

High voltages on a generator in a parallel system should be prevented because. it will cause high circulating current in the bus / other generators. it will damage the drive shaft. it will trip the GCR.

Over-voltage condition trips the generator. The time taken to trip the GCU depends on. time delay circuit. closing of fuel and hydraulic valves. amplitude of voltage.

Speed of an HMG is controlled by a. ID unit. CSD unit. swashplate.

A permanent magnet should have. high retentivity, low coercivity. low retentivity, high coercivity. low retentivity, low coercivity.

What will happen if the aircraft battery becomes overheated?. The power supply to the battery charger will be interrupted. The hot battery bus will be disconnected from the battery. The battery charger will switch to trickle charge mode.

When the temperature increases in a lead acid battery, the SG will. increase. decrease. remain the same.

On testing a generator it is found to require adjusting, where would you adjust it?. By means of a remote trimmer. On the GCU. In the cockpit on the flight engineers panel.

Control of hydraulically powered emergency electrical generator frequency is. by angle of swash plate. by IDG. by CSU.

When a ni-cad battery is fully charged. the electrolyte level is lower than normal. the electrolyte level is higher level than normal. the electrolyte level stays the same.

Electrical load on aircraft is controlled by. a GCU. a BPCU. an IRS.

A 4:1 step-up transformer receives 120VAC in its primary and has 1600 Ohms resistance in its secondary. What is the current drawn from the source?. 3 A. 1.2 A. 0.3 A.

After engine start using a Ni-Cad battery, the pilot observes on the battery charger indicator, an initial high current draw followed by a rapid decrease in current. no cause for concern. the battery is faulty. there is a problem with the charging circuit and he must shut-down the engines.

In a lead-acid battery after numerous checks, one cell has low reading. It is defective. It must be replaced. It needs topping up.

A short range passenger aircraft has complete electrical failure. What time duration would the battery be expected to power essential equipment?. 60 minutes. Forever. 30 minute.

An external power plug has two short pins. These are used for. a guide for correct alignment of the plug in the socket. the interlock circuit. ground handling bus.

The purpose of a synchronising bus bar is. to enable two propeller systems to be synchronised. to allow monitoring and trimming from the flight deck. to monitor total current load.

To confirm the state of charge of a ni-cad battery. subject the battery to load and check the voltage. measure the discharge time. subject the battery to load, check voltage and check the SG of each cell.

Circulating currents are associated with. AC generators in parallel. DC generators in parallel. AC and DC generators in parallel.

Generator brush bedding. can be done on the aircraft. should only be done if 50% of the width and 80% of the length is already being done. should not be done on the aircraft.

Pitot tubes are heated by. AC. AC or DC. DC.

Paralleling is used for. DC electrical generators only. AC electrical generators only. AC and DC electrical generators.

Battery charging procedures can be found in ATA. Chapter 24 Section 21. Chapter 31 Section 21. Chapter 24 Section 31.

In a carbon pile regulator, the resistive element is. in parallel with the field and changes resistance with changing length. in series with the field and changes resistance with changing length. in series with the field and changes resistance with surface area contact.

Maximum battery temperature on charging before protection circuit starts is. 144 degrees C. 71 degrees F. 144 degrees F.

If an aircraft has no battery charger, the battery is charged by. constant current until a predetermined limit when it automatically switches to constant voltage. constant current. constant voltage.

The output of a carbon pile regulator with no variation of loading is. stationary. pulse width modulating. fluctuating.

In a transistor voltage regulator, the voltage output is controlled by. zeners and transistors. diodes and transformers. transformers and transistors.

A paralleled relay for a DC system is energised and connected by. voltage and current coil. current coil. voltage coil.

Increasing the real load primarily. increases output voltage and increases frequency. decreases output voltage. decreases frequency.

Inductive reactive load causes. increase in torque only. no effect on torque but produces extra heat dissipated. increase in torque and increase in heat dissipated.

The power factor of an AC generator identifies the proportion of. apparent power from the generator that does work. real power from the generator that does work. reactive power from the generator that does work.

Differential protection in an AC system protects against. a reverse current flowing from the battery. line-line, line-line-line, line-earth faults. short circuits.

When resetting the CSD on the ground, the engine should be. rotating at idle. stationary. rotating at Nsync.

One of the main purposes of a CSD is to. enable generators to be paralleled. maintain constant load on the generator. prevent engine overload.

In an undervolt condition in an AC generator system, the most likely consequence is. activation of the time delay circuit. deactivation of the field regulatory TRs. energise the bus tie relay.

If voltage and frequency of the generator drop to zero in flight, it would be an indication that the. bus tie interlock is inoperative. phase sequence detection circuit has operated. CSD driveshaft had sheared.

Assuming all systems are operating normally, as aircraft electrical load increases, generator output voltage will. decrease and amperage output increases. increases and amperage output increases. remain constant and amperage output increases.

When installing multiple batteries on aircraft, they are connected in. either parallel or series and switched between as an option. series. parallel.

What is the small pin on the DC ground power connector?. Ground or earth. Positive to battery relay. Positive to external power relay.

How is RAT driven?. Airstream. Compressor. Fan.

How is an aircraft battery rated?. Ampere hours. Watts. Joules.