engine electrical systems Flashcards
what determines the frequency of an alternator output
the speed of rotation of the rotor and the number of poles
how many phases are used in most aircraft AC alternator systems
three
what are multiple generator systems paralleled
to ensure that each generator shares the load
what DC alternator system component prevents battery reverse-current flow through the armature
the reverse current relay or rectifier
what is used to control DC generator voltage
field current strength
what does an ammeter/loadmeter indicate when it is connected in the generator OUTPUT lead and the engine is operarting
the current leaving the generator, electrical system load
what does an ammeter/loadmeter indicate when it is connected in the battery POSITIVE lead and the engine is operating
whether the generator is supplying enough current to charge the battery or the battery is discharging
where are generator rating and performance data located
they are stamped on a data plate attached to the generator
why is a series wound motor commonly used as a reciprocating engine starter
because it has a high starting torque under heavy load conditions
what type of DC motor is commonly used for a reciprocating engine starter
a series wound motor
what is the purpose of bonding wires on powerplant installations
to provide current return paths, prevent static discharge, and protect the aircraft and personnel from lighting discharge
what is an indication of a dirty, worn, starter commutator
it is excessively noisy and the starter drags
what kind of wire is used for wires running close to exhaust stacks or heating ducts
wire with high temperature insulation material
how does a voltage regulator control the voltage of an alternator
regulating the voltage OUTPUT of the DC exciter
Name at least two methods that are used to maintain 400 Hertz alternator output frequency on large turbojet/turbofan engines
- constant speed drives
- integrated drive generators
- variable-speed constant frequency (VSCF) power systems
what is the maximum slack allowed between the supports of a single wire or bundle installation
not over 1/2 inch
which wire size is the largest AWG 10 or AWG 14
AWG 10
what is the size standard for electrical wire used in U.S manufactured aircraft
The American Wire Gage (AWG)
What are the operating modes of a turbine engine starter-generator
it operates first as a starter, then as a generator after the engine is operating
what are the components of a direct cranking electric starter system
M.R ED
electric motor
reduction gears
automatic engaging/disengaging mechanism
what are three types of DC motors
series, shunt, compound
what are the major parts of a DC motor
Brushes
Armature
Field
Frame
( B.A.F.F )
