Term
| How can the remaining service life of starter-generator brushes be determined? |
|
Definition
| visually inspecting the wear groove remaining on the brushes |
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|
Term
| What components of the starter-generator require periodic inspection? |
|
Definition
| Commutator and brushes should be inspected for wear beyond operational limits |
|
|
Term
| Between field and armature windings in starter-generators, which ordinarily receive current for operation in the start mode |
|
Definition
| Both receive current for operation in the start mode |
|
|
Term
| What are possible sources of low pressure compressed air used for starting jet transport A/C equipped with air turbine starters? |
|
Definition
GPU
APU
compressed bleed air from an already running engine |
|
|
Term
| When should ignition ideally occur? |
|
Definition
| A specific number of degrees before the piston reaches top dead center on the compression stroke |
|
|
Term
| Why are dual magnetos used in the engine ignition system |
|
Definition
| To improve combustion efficiency and provide redundancy for safety |
|
|
Term
| Why is magneto timing so important? |
|
Definition
| The engine will run rough or not at all if not timed properlly |
|
|
Term
| What function does a magneto perform? |
|
Definition
| produces a high voltage that forces a spark to arc across a spark plug gap |
|
|
Term
| Name the components of a high tension magneto system |
|
Definition
rotating magnet
soft iron core
pole shoes |
|
|
Term
| Name the 3 main circuits of a high tension magneto system |
|
Definition
Magnetic
primary and secondary winding |
|
|
Term
|
Definition
| A point a few degrees past neutral position of a rotating magnet |
|
|
Term
| How does a magneto produce the High voltage required to fire a spark plug? |
|
Definition
| when the magnet is in the E-gap position, the primary points open, interrupting the current flow in the primary circuit inducing a high voltage in the secondary coil |
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|
Term
| what reduces arcing in the points and also aids the collapsing of the magnetic field in a magneto |
|
Definition
|
|
Term
| What is the P-lead and how does it function |
|
Definition
| connects the ignition switch to the primary circuit of the magneto. When the ignition switch is off the P-lead grounds the magneto, and opens the circuit to the mag when its switched to left or right. |
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|
Term
| what is a magneto timing light used for, and what does it indicate |
|
Definition
| it is used for internal and engine to magneto timing, and indicates when the magneto points open. |
|
|
Term
| why are turbine engine igniters generally not susceptible to carbon fouling |
|
Definition
| the high energy sparks clean off any deposits on the firing end |
|
|
Term
| what is the function of a duty cycle in relation to a turbine engine ignition system |
|
Definition
| operation of the ignition system for a given amount of time, followed by a minimum cooling down period |
|
|
Term
| what are the 3 main components of a turbine engine ignition system |
|
Definition
| exciters, leads, igniters |
|
|
Term
| when the engine is operating, what does an ammeter indicate when connected to the battery positive lead and generator output lead |
|
Definition
Battery positive lead- indicates whether the battery in charging or discharging
Generator output lead- indicates the current produced by the generator |
|
|
Term
| what is done to ensure that each generator shares the load in a multiple generator system |
|
Definition
|
|
Term
| where would you find generator rating and performance data |
|
Definition
| on the generator data plate |
|
|
Term
| how is the voltage of a DC generator controlled |
|
Definition
| by varying the field current strength |
|
|
Term
| what is the most common type of alternator used in most aircraft AC systems |
|
Definition
|
|
Term
| how does a voltage regulator control the voltage of an alternator |
|
Definition
| by regulating the voltage output of the DC exciter |
|
|
Term
| what does the speed of rotation and number of poles of an alternator determine |
|
Definition
| the frequency of the alternator output |
|
|
Term
| what are some of the methods used to maintain 400 Hertz alternator output frequency on large turbojet or turbofan engines |
|
Definition
constant speed drives
integrated drive generators
and variable-speed constant frequency |
|
|
Term
| name the major parts of a DC motor |
|
Definition
armature
field
brushes
and frame assembly |
|
|
Term
| name the components of a direct cranking electric starter system |
|
Definition
electric motor
reduction gears
and automatic engaging and disengaging mechanism |
|
|
Term
| name 3 types of DC motors |
|
Definition
| series, shunt, and compound |
|
|
Term
| what type of DC motor is commonly used for a reciprocating engine starter and why |
|
Definition
| series wound motor because it has high starting torque under heavy load conditions |
|
|
Term
| what are the operating modes of a turbine engine starter generator |
|
Definition
| operates first as a starter, then as a generator once the engine is running |
|
|
Term
| what is a possible indication when a starter drags |
|
Definition
| dirty or worn starter commutator |
|
|
Term
| where would wire with high temp. insulation material be used |
|
Definition
| when the run close to high temp. areas |
|
|
Term
| what is the size standard for electrical wire used in US manufactured aircraft |
|
Definition
|
|
Term
| how are wire sizes represented |
|
Definition
|
|
Term
| what is the maximum slack allowed between the supports of a single wire or bundle installation |
|
Definition
|
|
Term
| why are wires bonded on powerplant installations |
|
Definition
| to provide a current return path for electrical accessories, and to prevent static discharge |
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