Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
35 Cards in this Set
- Front
- Back
|
How can the remaining service life of starter-generator brushes be determined? |
By visually inspecting the amount of wear grooves remaining on the brushes |
|
|
What components of the starter-generator require periodic inspection? |
Both commutator and brushes should be inspected for wear beyond operational limits |
|
|
Between field and armature windings in starter-generators, which ordinarily receive current for operation in the start mode? |
Generally, both field and armature receive current for operation in the start mode |
|
|
What are possible sources of low pressure compressed air used for starting jet transport aircraft equipped with air turbine starters? |
A GPU, APU, compressed bleed air from an already running engine |
|
|
When should ignition ideally occur? |
A specific number of degrees before the piston reaches top dead center on the compression stroke |
|
|
Why are dual magnetos used in the engine ignition system? |
To improve combustion efficiency, and provide redundancy for safety |
|
|
Why is magneto timing so important? |
For an engine to run properly, the spark plug in a cylinder has to fire at a specified time. To produce the required energy for the spark at the required time, the magneto must be in the E-gap position, the breaker points must start to open, and the distributor must be electrically aligned with the particular cylinder. If any of these requirements are not correctly adjusted, the engine will run rough or may not run at all. When preparing a magneto for installation, first the internal timing must be correctly adjusted, the. Magneto-to-engine timing is adjusted |
|
|
What function does a magneto perform? |
It produces a high voltage that forces a spark to arc across a spark plug gap |
|
|
Name the components to a high tension magneto system |
A permanent multipole rotating magnet, soft iron core, pole shoes |
|
|
Name the three main circuits if a high tension magneto system |
Magnetic, primary, secondary |
|
|
What is an E-gap angle? |
It is a point a few degrees beyond neutral position of a rotating magnet where maximum magnetic field stress exists |
|
|
What reduces arcing in the points and also the collapsing of the magnetic field in a magneto? |
A capacitor |
|
|
How does a magneto produce the high voltage required to fire a spark plug? |
In the rotation cycle, when the magnetic rotor is in the E-gap position, the primary points open, which interrupts the current flow in the primary circuit causing a high rate of flux change in the core, and inducing a pulse of high voltage in the secondary coil |
|
|
What is the P-lead and how does it function? |
The p-lead connects the ignition switch to the primary circuit if the magneto. When the ignition switch is turned off, the P-leads in Both magnetos are grounded. When the ignition switch is turned to the "LEFT" position, the right magneto is grounded, so that only the left magneto operates, and visa versa |
|
|
What is a magneto timing light used for, and what does it indicate? |
It is used for both internal magneto timing and magneto-to-engine timing, and indicates the exact instant the magneto points open |
|
|
Why are turbine engine igniters generally not susceptible to carbon fouling? |
Because the high energy sparks they produce clean off any deposits on the firing end |
|
|
What is the function of a duty cycle in relation to a turbine engine ignition system? |
A duty cycle allows the operation of the ignition system for a given amount of time, and is then followed by a minimum specified cooling down period |
|
|
What are the three main components of a turning engine ignition system? |
Ignition excites, high tension leads, igniters |
|
|
When the engine is operating, what does an ammeter/loadmeter indicate when connected to: 1 battery positive lead? 2 generator output lead? |
When connected to the battery positive lead, the ammeter indicates whether the battery is charging or discharging. When connected to the generator output lead, it indicates the current produced by the generator, or electrical system load |
|
|
What is done to ensure that each generator shares the load in a multiple generator system? |
The generators are paralleled |
|
|
Where would you find generator rating and performance data? |
On the data plate attached to the generator |
|
|
How is the voltage of a DC generator control the voltage of an alternator? |
By regulating the voltage output of the DC exciter |
|
|
When does the speed of rotation and number of poles of an alternator determine? |
The frequency of the alternator output |
|
|
What are some of the methods used to maintain 400 hertz alternator output frequency on large turbojet it turbofan engines? |
Constant speed drives, integrated drive generators, and variable-speed constant frequency power system |
|
|
Name the major pets if a DC motor |
The armature, field, brushes and frame assemvly |
|
|
Name the components. If a direct cranking electric starter system |
An electric motor, reduction gears, and an automatic engaging system and disengaging mechanism |
|
|
Name three types of DC motors |
Series, shunt, compound |
|
|
What type of DC motor is commonly used for a reciprocating engine stater and why? |
A series wind motor is commonly used because it had a high starting torque under heavy load conditions |
|
|
What are the operating modes of a turbine engine starter generator? |
It operates first as a starter, then as a generator once the engine is running |
|
|
What is a possible indication when a starter drags? |
A dirty or worn starter commutator |
|
|
Where would wire with high temperatures insulation material be? |
When they run close to high temperature areas such as exhaust stacks it heating ducts |
|
|
What is the size standard for electrical wire used in U.S. Manufactured aircraft? |
American wire gauge |
|
|
How are wire sizes represented? |
By a number gauge size. The smaller wires are represented by larger numbers. The smallest size wire normally used in aircraft is 22 gauge |
|
|
What is the maximum slack allowed between the supports if a single wire or bundle installation? |
Not over 1/2 inch |
|
|
Why are wires bonded on power plant installation? |
To provide a current return path for electrical accessories, and to prevent static discharge |
