AEIS CHAPTER 2 Flashcards
What is a generator
electromagnetic device that converts mechanical energy to electrical energy by electromagnetic induction
how are DC batteries used in aircrafts
used for emergency/standby purposes only
an aircraft dc generator is the i) of power and is also used to maintain the ii)
main source, aircraft battery at its fully charged condition
Aircraft DC generator is used for
normal operation
i) of armature affects the voltage produced by a generator
speed
i) of ii) field affects the voltage produced by a generator
strength, magnetic
number if i) affects the voltage produced by a generator
conductors connected in series with the armature
DC generator is made up of a i) and ii)
stator, rotor(shaft)
the stator in a DC generator is i)
stationary
the rotor(shaft) in a DC generator is i)
moving/turning
the magnetic frame(yoke) in the stator provides i) for the poles
mechanical support
the magnetic frame(yoke) in the stator acts i) for the machine
protecting cover
the magnetic frame(yoke) in the stator provides i) for flux produced
a path
the poles in the stator is made of i)
silicon steel plates (laminations) riveted together
the poles in the stator provides a i) for the magnetic flux
low resistance path
the poles in the stator provides i) for the field coils
support
the field coils in the stator produces i)
magnetic flux
the brushes and bearings in the stator is made of i)
carbon and copper alloy
the brushes and bearings collect i) from the ii) and delivers it to the iii)
current, commutator segments, external load circuit
the armature core in the rotor consists of i)
steel laminations insulated from each other
the armature core in the rotor provides a i) for the magnetic flux
low reluctance path
the armature windings in the rotor generates i) if the machines is a generator
EMF
the armature windings in the rotor allows the i) and develops a ii) if the machine is a motor
flow of current, force
the commutator in the rotor facilitates the i) from the ii)
collection of current, armature conductors
the commutator in the rotor rectifies the i) to ii) in the external load circuit
AC current to DC current
a series DC generator is a i) generator in which the field winding is in ii) with the armature winding
self-excited, series
a shunt DC generator is a i) generator in which the field winding is in ii) with the armature winding
self-excited, parallel
a compound DC generator is a i) generator in which the field winding is a ii)
self-excited, combination of series and shunt wound generators
a seperately-excited DC generator is a i) generator in which the field winding and armature are
seperately-excited, seperated
the two methods of winding the armature conductors are
wave winding and lap winding
wave winding is also known as i)
2 circuit winding/series winding
lap winding is also known as i)
multiple circuit winding/parallel winding
in wave winding, the windings i) overlap
do not
in lap winding, the windings i) overlap
do
in wave winding, the number of parallel paths is i) regardless of ii)
two, number of poles
in lap winding, the number of parallel paths is i) the number of poles
the same as
series windings produce i)
high voltage, low current generators
wave windings produce i)
high current, low voltage generators
in wave windings, each path supplies i)
the total current output
in wave windings, i) are neccesary
2 sets of brushes
in lap winding, the total current output divides i)
equally among the paths
in lap winding, there are as many i)
sets of brushes as the machine has poles\
formula for the EMF generated for a Wave-wound armature
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formula for the EMF generated for a Lap-wound armature
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voltage regulators is used to control i)
the strength of the field
voltage regulators is used to maintain a i) from the generator under ii)
a constant voltage, all conditions of speed and load
the three types of voltage regulators are
carbon-pile voltage regulator, variable resistor voltage regulator, solid-state voltage regulator
the reverse-current cut out relay prevents the i) when ii), preventing the iii)
battery from discharging through the generator, Vgen < Vbatt, armature from burning
the current limiter protects i)
the generator from excessive loads
what is a GCU
Generator Control Unit
a GCU consists of i), ii) and iii) from left to right according to the circuitry
Voltage regulator, current limited, reverse-current cut out relay
what are the basic equipment to monitor DC power onboard aircraft
ammeter and voltmeter
when designing aircraft electrical power distribution system, power consuming equipment must not be i) in the event of ii) unless iii)
deprived of power, power source failures, total power demand exceeds available supply
when designing aircraft electrical power distribution system, i) on the distribution system must have a ii)
faults, minimum effect on system
when designing aircraft electrical power distribution system, i) faults must not ii) to other equipment
power consuming equipment, endanger the supply of power
one of the advantages of paralleling genrators is that there will be i) if a generator fails
no break in supply
one of the advantages of paralleling genrators is that the system can handle i) and ii) to improve iii)
high transient loads, share the loads equally, life expectancy
one of the disadvantages of paralleling generators is that it requires i) and ii)
additional circuitry, it complicates the system
the Hot battery bus is for i) and is connected ii)
vital / critical services, directly to the battery
the main bus is for i) and can be supplied from ii)
essential services, from a generator or batteries
the avionics bus is for i) and is supplied from a ii)
non essential services, generator
DC motors have i) arrangements unlike AC motors
commutator
DC motors do not depend on i) for speed control and are more suited for ii)
input frequency, fast-changing speed applications
DC Generator turns the i) to outpur ii)
armature, DC voltage
DC Motor inputs i), making the ii) and outputs iii)
DC power, armature rotate, torque
In a series wound motor, the field windings and armature are i)
connected in series
a series wound motor has a high i) and good ii)
starting torque, acceleration
a series wound motor can never run i)
without a load
a series wound motor can be started on a i)
full load
In a shunt wound motor, the field windings and armature are i)
connected in parallel
a shunt wound motor has a i) characteristic
constant-speed
in a shunt wound motor, the i) is proportional to ii)
torque proportional to armature current
a shunt wound motor must be started on a i) or ii)
light, no load
a compound wound motor has i) and i) in speed
good starting torque, good stability
a compount wound motor provides the benefits of i)
series and shunt wound motors
a starter generator initially operates as a i) to ii). subsequently, it will start to act as a iii)
DC motor, crank the engine, generator
using a starter generator helps to save i) by replacing individual members
size and weight
one disadvantage of using a starter generator is that the generator output is i) to maintain at ii)
difficult, low engine rpm
starter generators are usually used on i) aircraft that maintains a ii)
turbine powered, relatively high engine rpm
