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37 Cards in this Set
- Front
- Back
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How can the remaining life of a starter-generator brushes be determine?
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Visual inspecting the amount of wear grove remaining on the brush...
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What components of the starter-generator require periodic inspection?
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Both commutator and brushes should be inspected for wear beyond operational limits.
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Between field and armature windings in starter-generators, which ordinary receive current for operation in the start mode |
Generally both field and armature receive current for operation in the starter mode |
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What are possible sources of low pressure compressed air used for starting jet transport category aircraft equipped with air turbine starters?
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GPU(ground power unit) , APU (on board auxiliary power) or compressed air from already running engine.
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When should ignition ideally occur?
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A spacific number of degrees (as determine by manufacturer) before the piston reaches Top Dead Center on compression stroke...
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Why are dual magnetos used in engine ignition timing? |
To improve combustion efficiency and redundancy for safety... |
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Why is magneto timing so important?
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For engine to run properly ,the sparkplug has to fire at a specific time. To produce the required energy for the spark at the required time the mag must be in E-gap position, the breaker point must start opening and the distributor must be electrically alighted with a particular cylinder. If an of this requirement are not met , the mag may run rough or may not run at all. When preparing for installation of a mag, the internal timming must be adjusted first then the mag to engine fallows....
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What function does a mag perform?
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It produces a high voltage that forces a spark to arc across a spark plug gap....
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Name the components of a high tension mag system ?
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Permanet multipole rotating magnet , soft iron core, and pole shoes..
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Name the 3 main circuits of a high tension mag system?
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Magmetic, primary and secondary ...
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What is an E-gap angle? |
A point a few degrees beyond neutral position of a rotating magnet where the maximum field stress exist.. |
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What reduced arcing in the points an also aids collapsing of the magnetic field in a Magneto?
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Capacitor...
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How does a magneto produce the high voltage required to fire a spark plug?
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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. ...
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What is a P-lead and how does it function?
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P-Lead connects the ignition switch to the primary circuit of the mag. When the ignition switch is turned off, the P-leads on both mag are grounded. When the ignition switch is turned to the [Left] position , the right mag is grounded , so that only the left mag operates and visa versa...
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What is mag timing light used for, and what does it indicate?
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It used in both internal and mag to engine timing , and it indicated the exact instant the mag points open...
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Why are turbine igniters generally not susceptible to carbon fowling?
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High energy sparks they produce clear off any deposits on the firing end...
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What is the function of a duty cycle in relation to a turbine engine ignition system?
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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..
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What are the 3 main components of a turbine ignition system?
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Ignition exciter(box) high tension leads, igniters...
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When the engine is operating, what does an ammeter/loadmeter indicate when connected to: 1. Battery (+) lead ? 2. Generator out put lead? |
When connected to the battery (+) lead, the ammeter indicated the battery is charging or discharging. When connected to generator out put lead, indicated the current produced by the generator or electrical load....
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What is done to ensure that each generator shares the load in a multiple generator system?
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The generator are Paralleled..
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Where were you find generator rating and performance data?
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On the date plate attached to the generator...
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How is voltage of a DC generator controlled?
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By varying the field current strength...
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What is the most common type of alternator used in most aircraft AC system?
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3 phase alternador...
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How does a voltage regulador control the voltage of an alternador?
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By reagulating the voltage output of the DC exciter..
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What does the speed of rotation and number of poles of an alternador determine?
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The frequency of the alternador output..
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What are some of the methods used to maintain 400 Hertz alternador output frequency on large turbojet or turbofan engines?
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Constand speed drives (csd) or integrated drive generator(IDG), variable-speed constant frequency (VSCF) power systems..
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Name the major parts of a DC motor? |
Armature, field, brushes and frame assembly... |
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Name the components of a direct cranking electric starter system?
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Electric motor , reduction gears , and automatic engaging and disengaging mechanism..
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Name 3 types of DC motors.
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Series , shun and compound...
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What type of DC motor is commonly used for a reciprocating engine starter and why?
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Series wound motor ,its high starting torque under heavy load condition is why it used.... |
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What are the operating modes of a turbine engine starter generator?
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First as a starter, then generator once the engine is running...
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What is a possible indication when a starter drags?
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Dirty or worn starter commutator...
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Where would wire with high temperature insulation material be used?
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When they run close to high temperature areas such as exhaust stacks or heating ducts..
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What is the size standard for electrical wire used in US manufacture aircraft?
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American Wire Gauge (AWG)
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How re wire sizes represented?
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By a numbered gauge size. The small wired are represented large numbers. The smallest wire used in aircraft is 22-guage...
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What is the maximum slack allowed the support of a single wire or bundle installation?
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Not over a inch...
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Why are wires bounded on powerplant installations?
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To provide a current return path for electrical accessories, and to prevent static discharge...
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