Engine Electrical System Flashcards
Name the component of basic magnetic circuit
Permanent rotating magnetic , soft iron core , pole shoes
How would seat a newly installed generator brushes to the commutator
Use fine grain sandpaper place around the commutator with he sanding surface facing outward . Turn the armature in normal direction of rotation until the face of the brushes is properly contour. Remove the sandpaper and blow out any residue with compress air
- Remove cover
- Remove bushes.
- Install sandpaper
- Install new brushes
- Rotate generator
6.remove bushes - Remove sand paper
8.blow out generator - Install new brushes
- Install cover
When is it necessary to replace the brushes in a starter ?
When is half of their original length
Where is the generator racing and performance data located
On the data plate attached to the generator
What unite makes 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 generator
Voltage regulator
What determines the frequency of the voltage of alternotor
Depends on the speed of rotation of the rotor and and the number of poles
How is alternator frequency maintained
Using constant speed drive unit between the engine and the alternator
What are the three basic type of dc motor
Series , shunt , and compound motor
Name of the parts of dc motor
Armature , brushes commutator and field frame ( ABC-F)
Why is a starter generator system, used on many turbine engines
Save space and weight . Operates as a starter motor during engine starting. When engine reach it self accelerating speed it become a generator which supplies ac power for aircraft system
Why should stranded wire be used in powerplant application
Less likely to fatigue and break from vibration
What is American wire gauge system of designating electrical wire size
Number is assign to wire according to it cross- sectional area . The smaller the gauge number the larger the wire
What is open wiring
Any wire , wire group, wire bundle that’s not enclosed in conduits
What methods are used to control the voltage output of a DC aircraft generator?
Vibrating type voltage regulator, three unit, and Carbon pile
What aircraft electrical system normally doesn’t have a fuse or circuit breaker
Starter circuit
What are the causes of excessive arcing at the generator brushes
Commutator is dirty, rough or out around , worn or binding of brushes and low spring tension
Why are protective cover place on some electrical switches?
To prevent switch from accidentally being actuated
When install a single wire wire bundle, whole bunch like it’s normally allowed between the suppor
Should normally not exceed .5”
What precaution should be take when running wires close to heating duct or exhaust stack
Insulated with high temperature resistant material
What is the indication on the amp meter when the engine is running and the AC generator is producing power
The power is being produced
Why are multi generator systems paralleled
To ensure generator shares the load
What DC alternator component Prevents battery reverse current flow into the Armature
The rectifier
How many phases are using most aircraft AC alternator systems
Three phase
Name some of the methods that are used to maintain 400 Hz alternator output frequency on a large turbojet/turbofan engine
CSD, IDG, and variable speed constant frequency power system
What are the components of direct cranking electric starter system
Electrical, motor, reduction gear, and automatic engaging and disengaging mechanism
What type of DC motor is commonly used for an aircraft engine starter
Series wound motor
Why is series wound motor commonly used as on aircraft engine starter
It has high starting torque under heavy load condition
