Generator Flashcards
frequency = Rotor magnet poles x RPM / x
120
frequency = rotor pole pairs x RPM / x
60
What is the equation for frequency using rotor magnetic poles?
f = P x RPM / 120
What is the equation for frequency using rotor pole pairs?
f = PP X RPM / 60
400 HZ = x RPM
24000
During cruising flight, when the throttle is pulled back on an aeroplane equipped with a constant speed-propeller, the propeller pitch automatically decreases/increases and the RPM increases/decreases/does nothing.
Decreases and does nothing.
Window screens in flight use a singlephase/3phase.
3 phase
Fuel pumps use a singlephase/3phase.
Single phase
What value is the phase voltage?
115v
Whats the line voltage?
200v
Blank is dependant of magnet rotation speed and number of poles on rota.
Frequency
What is used to lubricate the independent drive generator?
Oil.
Whats an inverter in a generator?
DC to AC
How do you regulate the constant sped drive?
Using hydraulics.
In an AC power generation system, the constant speed drive unit is… a electrical/hydromechanical unit that can/cannot be disconnected from the engine drive shaft during flight.
Hydro and can
In order to produce an alternating voltage of 400 Hz, the RPM required for a 6-pole AC generator is…
8000
When climbing out at a low altitude in an aircraft fitted with an Split Bus Bar System, the Voltage reading from GEN 1 (IDG) suddenly spikes up to 1000 V which engages a caution annunciator. What is the pilot’s immediate action? = nothing, the system is protected by the blanks and gcu which does not need pilot input.
Circuit breakers
When the “disconnect” switch is activated on the electrical panel, it disconnects… blank from the gearbox.
Independent drive generator
What monitors the oil pressure and tempurature?
Constant speed drive,
In an AC system, what is a differential fault? It is a large difference between… blank and its busbar.
Generator
The APU of a large passenger jet airliner has its own AC generator that… supplies the aircraft with three-phase x V, x Hz AC.
115 V and 400Hz
How do you know if there is a failure in the CSD/GCU? Oil pressure increases/ decrease and oil temperature increases/decreases. And you should disconnect the IDG.
Oil pressure decreases whilst oil temp increases
An AC generator driven by a constant speed drive (CSD)… requires a blank controller to maintain constant voltage under load.
Voltage
When can the IDG disconected?
When engine running?
When can the IDG be connected?
With engines shut down.
Where does the initial electrical signal in a generator come from?
Permanent magnet generator PMG
A generator control unit has a blank regulator.
Variable.
What does a TRU (transformer rectifier unit) do?
Ac to Dc
There is a generator control switch on the flight deck. Using the annex above, which generator does this switch directly control?
Excitor Generator
What is a Transformer Rectifier Unit (TRU) used for? To convert from x to DC, usually to a higher/lower voltage.
AC to DC, usually to a lower voltage
The primary function of a constant speed drive in an AC generating system is to… drive blank at a constant blank.
Drive generator at a constant speed.
Out of GEN and BAT which one only has positive current
BAT
A starter-generator is an electrical generator that… performs as an blank blank during engine start.
Electric motor
On an aircraft using AC as primary power supply, the batteries are charged in flight from…
Transform rectify unit (TRU)
A rectifier is used to…
AC to DC
The main purpose of a Constant Speed Drive unit is to… maintain a constant blank.
Frequency.
The frequency of the current provided by an alternator depends on…
Rotation speed
As regards the Generator Control Unit (GCU) of an AC generator, it can be said that:
1) the GCU controls the AC generator voltage
2) modern GCUs are provided with a permanent indication to record the failure
3) all the commands originating from the control panel are applied via the GCU, except dog clutch release
4) the Auxiliary Power Unit (APU) provides the excitation of the AC generator as soon as the APU starts up
The combination regrouping all the correct statements is…
2,3
What is a voltage regulator used for? To control voltage from… x during varying load and speed.
Generators
Alternating current can be derived from direct current by…
An inverter
- Low oil pressure in the CSD
- Slight variation about the normal operating frequency
- High oil temperature in the CSD
- Excessive variation of voltage and kVAR
1,3
Frequency wild” in relation to a AC generation system means the generator… output frequency varies with blank speed.
Engine
What is connected to AC1 in an airbus?
Essentials bussbar
If AC1 goes to 0 volts what happens?
RAT deploys
When would you operate the IDG disconnect?
High oil pressure or low oil tempurature
What does the constant soeed drive unit.
Controls the rotor to 12,000rpm to allow for 400 constant hz in the generator.
Where is the generator disconnect?
Between the engine and the IDG.
The caution warning on the left hand IDG is shown and the temperature does not begin to drop. What can the pilots assume about that IDG? That the blank supply is lost and cannot be recovered in flight.
That the electrical supply is lost and cannot be recovered in flight.
What occurs to current and torque during a DC generator’s armature runaway?
Current and torque decrease
One of the purposes of the starter-generator is to start the blank blank until reaching self-sustaining speed.
Core engine
When the engine fire shut-off handle is pulled, what is the effect on the AC generator? The exciter control relay and the blank breaker open.
Generator
True or false : Each generator is connected to its own dedicated AC bus bar.
True
The function of the generator breaker is to close when the voltage of the…generator is less/greater than battery voltage and to open when the opposite is true
Greater
