Powerplant Systems & Components: Engine Electrical Systems 🔊 Flashcards
How would you seat newly installed generator brushes to the commutator?
When new brushes are in a generator the faces must be shaped to provide maximum contact with commutator. To seat brushes, wrap sandpaper around the commutator, turn the armature in the normal direction of rotation until the face of the brushes is properly contoured. Remove the sandpaper and blow out any residue with compressed air.
When is it necessary to replace the brushes in a starter?
Once they are half their original length
Where is the generator rating and performance data located?
On the data plate attached to the generator
What units make up a DC generator three-unit regulator?
The voltage regulator, current limiter, and reverse current cutout
What method is used to control the voltage of an aircraft alternator?
The voltage regulator
What determines the frequency of the voltage of an alternator?
It depends upon the speed of rotation of the rotor and the 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 motors, shunt motors, and compound motors
Name the parts of a DC motor.
The armature, brushes, commutator, and field frame (ABC-F)
Why is the starter-generator system use on many turbine engines?
To save space and weight
Why should stranded wire be used in powerplant applications?
It is less likely to fatigue and break from vibrations
What is the American Wire Gauge (AWG) system of designating electrical wire size?
Gauge is assigned according to its cross-sectional area, the smaller the number the larger the wire
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 regulator, three-unit regulator, and carbon-pile
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?
Arcing can be caused by a commutator that is dirty, rough, or out of round. A common cause of arcing is worn or binding brushes or when brush spring tension is too low.
When installing single wires or wire bundles, how much slack is normally allowed between supports?
Slack between supports should normally not exceed .5”
What precaution should be taken when running wires close to heating ducts or exhaust stacks?
The 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
