Engine Electrical Systems Flashcards
Name the components of a basic magnetic circuit.
Permanent multi-pole rotating magnet, Soft Iron Core, Pole Shoes
How would you seat newly installed generator brushes to the commutator?
Remove Cover, Remove Brushes, Install Sandpaper, Install new Brushes, Rotate Generator, Remove Brushes, Remove Sandpaper, Blow out Generator, Install new Brushes, Install Cover
When is it necessary to replace the brushes in a starter?
Once they reach half their original length
Where is the generator rating and performance data located?
On the generator data plate
What units make up a DC generator three-unit regulator?
Voltage Regulator, Current Limiter, and Reverse Current Cutout
What method is used to control the voltage of an aircraft alternator?
Voltage Regulator
What determines the frequency of the voltage of an alternator?
Rotation speed of the rotor and number of poles
How is alternator frequency maintained?
Installing a constant speed drive (CSD) unit between the engine and alternator
What are the three basic types of DC motors?
Series, Shunt, Compound
Name the parts of a DC motor.
Armature, Brushes, Commutator, Field Frame
Why is the starter-generator system used on many turbine engines?
Save space and weight
Why should stranded wire be used in powerplant applications?
Less likely to fatigue and break from vibrations
What is the American Wire Gauge (AWG) system of designating electrical wire size?
A gauge number is assigned to the wire according to its cross-sectional area
What is opening wiring? (not an open circuit)
Any wire, wire group, or wire bundle not enclosed in conduit
What methods are used to control the voltage output of a DC aircraft generator?
Vibrating type voltage, three-unit, and carbon-pile regulators
What aircraft electrical system normally does not have a fuse or circuit breaker?
Starter circuit
Why are protective covers placed on some electrical switches?
To prevent the switch from accidentally being actuated
What are the causes of excessive arcing at the generator brushes?
Dirty, rough or out of round commutator and brushes that are worn, binding or low tension
When installing single wires or wire bundles, how much slack is normally allowed between supports?
Not to exceed 0.5 inches
What precaution should be taken when running wires close to heating ducts or exhaust stacks?
Wires should be insulated with a high temperature resistant material
What is indicated on the amp meter when the engine is running and the AC generator is producing power?
That power is being produced
Why are multiple generator systems paralleled?
To ensure that each generator shares the load
What DC alternator component prevents battery reverse current flow into the armature?
Rectifier
How many phases are used in most aircraft AC alternator systems?
Three
Name some methods that are used to maintain 400 Hertz alternator output frequency on large turbo jet/turbo fan engines.
Constant speed drives, integrated drive generators, variable speed constant frequency power systems
What are the components of a direct cranking electric starter system?
Electric Motor, Reduction Gears, Automatic engaging and disengaging mechanism
What type of DC motor is commonly used for an aircraft engine starter?
A series wound motor
Why is a series wound motor commonly used as an aircraft engine starter?
It has high starting torque under heavy load conditions
During engine run ups with systems running, if the battery is under excessive load, what should be done?
Turn off systems
If you have two generators wired in parallel and they both put out 60 AMPS, what would be your total amperage?
120 AMPS
In an aircraft with twin engines, how are the generators operated to supply the aircraft with power?
In Parallel
What’s the output of an AC generator?
Alternating current 120V or higher
